java.lang.Object
↳androidx.preference.Preference
Subclasses:
TwoStatePreference, DialogPreference, DropDownPreference, SeekBarPreference, SwitchPreferenceCompat, PreferenceGroup, PreferenceScreen, PreferenceCategory, EditTextPreference, ListPreference, MultiSelectListPreference, SwitchPreference, CheckBoxPreference
Gradle dependencies
compile group: 'androidx.preference', name: 'preference', version: '1.2.1'
- groupId: androidx.preference
- artifactId: preference
- version: 1.2.1
Artifact androidx.preference:preference:1.2.1 it located at Google repository (https://maven.google.com/)
Androidx artifact mapping:
androidx.preference:preference com.android.support:preference-v7
Androidx class mapping:
androidx.preference.Preference android.support.v7.preference.Preference
Overview
The basic building block that represents an individual setting displayed to a user in the
preference hierarchy. This class provides the data that will be displayed to the user and has
a reference to the SharedPreferences
or PreferenceDataStore instance that
persists the preference's values.
When specifying a preference hierarchy in XML, each element can point to a subclass of
Preference, similar to the view hierarchy and layouts.
This class contains a key that that represents the key that is used to persist the
value to the device. It is up to the subclass to decide how to store the value.
Developer Guides
For information about building a settings screen using the AndroidX Preference library, see
Settings.
Summary
Constructors |
---|
public | Preference(Context context)
Constructor to create a preference. |
public | Preference(Context context, AttributeSet attrs)
Constructor that is called when inflating a preference from XML. |
public | Preference(Context context, AttributeSet attrs, int defStyleAttr)
Perform inflation from XML and apply a class-specific base style. |
public | Preference(Context context, AttributeSet attrs, int defStyleAttr, int defStyleRes)
Perform inflation from XML and apply a class-specific base style. |
Methods |
---|
public boolean | callChangeListener(java.lang.Object newValue)
Call this method after the user changes the preference, but before the internal state is
set. |
public int | compareTo(Preference another)
Compares preference objects based on order (if set), otherwise alphabetically on the titles. |
protected Preference | findPreferenceInHierarchy(java.lang.String key)
Finds a preference in the entire hierarchy (above or below this preference) with the given
key. |
public Context | getContext()
Returns the of this preference. |
public java.lang.String | getDependency()
Returns the key of the dependency on this preference. |
public Bundle | getExtras()
Return the extras Bundle object associated with this preference, creating a new Bundle if
there currently isn't one. |
public java.lang.String | getFragment()
Return the fragment class name associated with this preference. |
public Drawable | getIcon()
Returns the icon of this preference. |
public Intent | getIntent()
Return the associated with this preference. |
public java.lang.String | getKey()
Gets the key for this preference, which is also the key used for storing values into
SharedPreferences or PreferenceDataStore. |
public final int | getLayoutResource()
Gets the layout resource that will be shown as the View for this preference. |
public Preference.OnPreferenceChangeListener | getOnPreferenceChangeListener()
Returns the callback to be invoked when this preference is changed by the user (but before
the internal state has been updated). |
public Preference.OnPreferenceClickListener | getOnPreferenceClickListener()
Returns the callback to be invoked when this preference is clicked. |
public int | getOrder()
Gets the order of this preference with respect to other preference objects on the same level. |
public PreferenceGroup | getParent()
Returns the PreferenceGroup which is this preference assigned to or null
if this preference is not assigned to any group or is a root preference. |
protected boolean | getPersistedBoolean(boolean defaultReturnValue)
Attempts to get a persisted java.lang.Boolean if this preference is persistent. |
protected float | getPersistedFloat(float defaultReturnValue)
Attempts to get a persisted java.lang.Float if this preference is persistent. |
protected int | getPersistedInt(int defaultReturnValue)
Attempts to get a persisted java.lang.Integer if this preference is persistent. |
protected long | getPersistedLong(long defaultReturnValue)
Attempts to get a persisted java.lang.Long if this preference is persistent. |
protected java.lang.String | getPersistedString(java.lang.String defaultReturnValue)
Attempts to get a persisted set of Strings if this preference is persistent. |
public java.util.Set<java.lang.String> | getPersistedStringSet(java.util.Set<java.lang.String> defaultReturnValue)
Attempts to get a persisted set of Strings if this preference is persistent. |
public PreferenceDataStore | getPreferenceDataStore()
Returns PreferenceDataStore used by this preference. |
public PreferenceManager | getPreferenceManager()
Gets the PreferenceManager that manages this preference object's tree. |
public SharedPreferences | getSharedPreferences()
Returns the SharedPreferences where this preference can read its
value(s). |
public boolean | getShouldDisableView()
Checks whether this preference should disable its view when it's action is disabled. |
public java.lang.CharSequence | getSummary()
Returns the summary of this preference. |
public final Preference.SummaryProvider | getSummaryProvider()
Returns the Preference.SummaryProvider used to configure the summary of this preference. |
public java.lang.CharSequence | getTitle()
Returns the title of this preference. |
public final int | getWidgetLayoutResource()
Gets the layout resource for the controllable widget portion of this preference. |
public boolean | hasKey()
Checks whether this preference has a valid key. |
public boolean | isCopyingEnabled()
Returns whether the summary of this preference can be copied to the clipboard by
long pressing on the preference. |
public boolean | isEnabled()
Checks whether this preference should be enabled in the list. |
public boolean | isIconSpaceReserved()
Returns whether the space of this preference icon view is reserved. |
public boolean | isPersistent()
Checks whether this preference is persistent. |
public boolean | isSelectable()
Checks whether this preference should be selectable in the list. |
public final boolean | isShown()
Checks whether this preference is shown to the user in the hierarchy. |
public boolean | isSingleLineTitle()
Gets whether the title of this preference is constrained to a single line. |
public final boolean | isVisible()
Checks whether this preference should be visible to the user. |
protected void | notifyChanged()
Should be called when the data of this Preference has changed. |
public void | notifyDependencyChange(boolean disableDependents)
Notifies any listening dependents of a change that affects the dependency. |
protected void | notifyHierarchyChanged()
Should be called when a preference has been added/removed from this group, or the ordering
should be re-evaluated. |
public void | onAttached()
Called when the preference hierarchy has been attached to the list of preferences. |
protected void | onAttachedToHierarchy(PreferenceManager preferenceManager)
Called when this preference has been attached to a preference hierarchy. |
protected void | onAttachedToHierarchy(PreferenceManager preferenceManager, long id)
Called from PreferenceGroup to pass in an ID for reuse. |
public void | onBindViewHolder(PreferenceViewHolder holder)
Binds the created View to the data for this preference. |
protected void | onClick()
Processes a click on the preference. |
public void | onDependencyChanged(Preference dependency, boolean disableDependent)
Called when the dependency changes. |
public void | onDetached()
Called when the preference hierarchy has been detached from the list of preferences. |
protected java.lang.Object | onGetDefaultValue(TypedArray a, int index)
Called when a preference is being inflated and the default value attribute needs to be
read. |
public void | onInitializeAccessibilityNodeInfo(AccessibilityNodeInfoCompat info)
Initializes an android.view.accessibility.AccessibilityNodeInfo with information
about the View for this preference. |
public void | onParentChanged(Preference parent, boolean disableChild)
Called when the implicit parent dependency changes. |
protected void | onPrepareForRemoval()
Called when this preference is being removed from the hierarchy. |
protected void | onRestoreInstanceState(Parcelable state)
Hook allowing a preference to re-apply a representation of its internal state that had
previously been generated by Preference.onSaveInstanceState(). |
protected Parcelable | onSaveInstanceState()
Hook allowing a preference to generate a representation of its internal state that can
later be used to create a new instance with that same state. |
protected void | onSetInitialValue(boolean restorePersistedValue, java.lang.Object defaultValue)
Implement this to set the initial value of the preference. |
protected void | onSetInitialValue(java.lang.Object defaultValue)
Implement this to set the initial value of the preference. |
public Bundle | peekExtras()
Return the extras Bundle object associated with this preference, returning null if
there is not currently one. |
public void | performClick()
Called when a click should be performed. |
protected void | performClick(View view)
Used by Settings. |
protected boolean | persistBoolean(boolean value)
Attempts to persist a java.lang.Boolean if this preference is persistent. |
protected boolean | persistFloat(float value)
Attempts to persist a java.lang.Float if this preference is persistent. |
protected boolean | persistInt(int value)
Attempts to persist an java.lang.Integer if this preference is persistent. |
protected boolean | persistLong(long value)
Attempts to persist a java.lang.Long if this preference is persistent. |
protected boolean | persistString(java.lang.String value)
Attempts to persist a java.lang.String if this preference is persistent. |
public boolean | persistStringSet(java.util.Set<java.lang.String> values)
Attempts to persist a set of Strings if this preference is persistent. |
public void | restoreHierarchyState(Bundle container)
Restore this preference hierarchy's previously saved state from the given container. |
public void | saveHierarchyState(Bundle container)
Store this preference hierarchy's frozen state into the given container. |
public void | setCopyingEnabled(boolean enabled)
Sets whether the summary of this preference can be copied to the clipboard by
long pressing on the preference. |
public void | setDefaultValue(java.lang.Object defaultValue)
Sets the default value for this preference, which will be set either if persistence is off
or persistence is on and the preference is not found in the persistent storage. |
public void | setDependency(java.lang.String dependencyKey)
Sets the key of a preference that this preference will depend on. |
public void | setEnabled(boolean enabled)
Sets whether this preference is enabled. |
public void | setFragment(java.lang.String fragment)
Sets the class name of a fragment to be shown when this preference is clicked. |
public void | setIcon(Drawable icon)
Sets the icon for this preference with a Drawable. |
public void | setIconSpaceReserved(boolean iconSpaceReserved)
Sets whether to reserve the space of this preference icon view when no icon is provided. |
public void | setIntent(Intent intent)
Sets an to be used for when this
preference is clicked. |
public void | setKey(java.lang.String key)
Sets the key for this preference, which is used as a key to the SharedPreferences or
PreferenceDataStore. |
public void | setLayoutResource(int layoutResId)
Sets the layout resource that is inflated as the View to be shown for this
preference. |
public void | setOnPreferenceChangeListener(Preference.OnPreferenceChangeListener onPreferenceChangeListener)
Sets the callback to be invoked when this preference is changed by the user (but before
the internal state has been updated). |
public void | setOnPreferenceClickListener(Preference.OnPreferenceClickListener onPreferenceClickListener)
Sets the callback to be invoked when this preference is clicked. |
public void | setOrder(int order)
Sets the order of this preference with respect to other preference objects on the same
level. |
public void | setPersistent(boolean persistent)
Sets whether this preference is persistent. |
public void | setPreferenceDataStore(PreferenceDataStore dataStore)
Sets a PreferenceDataStore to be used by this preference instead of using
SharedPreferences . |
public void | setSelectable(boolean selectable)
Sets whether this preference is selectable. |
public void | setShouldDisableView(boolean shouldDisableView)
Sets whether this preference should disable its view when it gets disabled. |
public void | setSingleLineTitle(boolean singleLineTitle)
Sets whether to constrain the title of this preference to a single line instead of
letting it wrap onto multiple lines. |
public void | setSummary(java.lang.CharSequence summary)
Sets the summary for this preference with a CharSequence. |
public void | setSummary(int summaryResId)
Sets the summary for this preference with a resource ID. |
public final void | setSummaryProvider(Preference.SummaryProvider summaryProvider)
Set a Preference.SummaryProvider that will be invoked whenever the summary of this preference
is requested. |
public void | setTitle(java.lang.CharSequence title)
Sets the title for this preference with a CharSequence. |
public void | setTitle(int titleResId)
Sets the title for this preference with a resource ID. |
public void | setViewId(int viewId)
Set the ID that will be assigned to the overall View representing this preference, once
bound. |
public final void | setVisible(boolean visible)
Sets whether this preference should be visible to the user. |
public void | setWidgetLayoutResource(int widgetLayoutResId)
Sets the layout for the controllable widget portion of this preference. |
public boolean | shouldDisableDependents()
Checks whether this preference's dependents should currently be disabled. |
protected boolean | shouldPersist()
Checks whether, at the given time this method is called, this preference should store/restore
its value(s) into the SharedPreferences or into PreferenceDataStore if
assigned. |
public java.lang.String | toString()
|
from java.lang.Object | clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait |
Fields
public static final int
DEFAULT_ORDERSpecify for Preference.setOrder(int) if a specific order is not required.
Constructors
public
Preference(Context context, AttributeSet attrs, int defStyleAttr, int defStyleRes)
Perform inflation from XML and apply a class-specific base style. This constructor allows
subclasses to use their own base style when they are inflating. For example, a
CheckBoxPreference constructor calls this version of the super class constructor
and supplies android.R.attr.checkBoxPreferenceStyle for defStyleAttr.
This allows the theme's checkbox preference style to modify all of the base preference
attributes as well as the CheckBoxPreference class's attributes.
Parameters:
context: The this is associated with, through which it can
access the current theme, resources, SharedPreferences
, etc.
attrs: The attributes of the XML tag that is inflating the preference
defStyleAttr: An attribute in the current theme that contains a reference to a style
resource that supplies default values for the view. Can be 0 to not
look for defaults.
defStyleRes: A resource identifier of a style resource that supplies default values
for the view, used only if defStyleAttr is 0 or can not be found in the
theme. Can be 0 to not look for defaults.
See also: Preference
public
Preference(Context context, AttributeSet attrs, int defStyleAttr)
Perform inflation from XML and apply a class-specific base style. This constructor allows
subclasses to use their own base style when they are inflating. For example, a
CheckBoxPreference constructor calls this version of the super class constructor
and supplies android.R.attr.checkBoxPreferenceStyle for defStyleAttr.
This allows the theme's checkbox preference style to modify all of the base preference
attributes as well as the CheckBoxPreference class's attributes.
Parameters:
context: The Context this is associated with, through which it can access the
current theme, resources, SharedPreferences
, etc.
attrs: The attributes of the XML tag that is inflating the preference
defStyleAttr: An attribute in the current theme that contains a reference to a style
resource that supplies default values for the view. Can be 0 to not
look for defaults.
See also: Preference.Preference(Context, AttributeSet)
public
Preference(Context context, AttributeSet attrs)
Constructor that is called when inflating a preference from XML. This is called when a
preference is being constructed from an XML file, supplying attributes that were specified
in the XML file. This version uses a default style of 0, so the only attribute values
applied are those in the Context's Theme and the given AttributeSet.
Parameters:
context: The Context this is associated with, through which it can access the
current theme, resources, SharedPreferences
, etc.
attrs: The attributes of the XML tag that is inflating the preference
See also: Preference.Preference(Context, AttributeSet, int)
public
Preference(Context context)
Constructor to create a preference.
Parameters:
context: The Context this is associated with, through which it can access the
current theme, resources, SharedPreferences
, etc.
Methods
protected java.lang.Object
onGetDefaultValue(TypedArray a, int index)
Called when a preference is being inflated and the default value attribute needs to be
read. Since different preference types have different value types, the subclass should get
and return the default value which will be its value type.
For example, if the value type is String, the body of the method would proxy to
.
Parameters:
a: The set of attributes
index: The index of the default value attribute
Returns:
The default value of this preference type
public void
setIntent(Intent intent)
Sets an to be used for when this
preference is clicked.
Parameters:
intent: The intent associated with this preference
public Intent
getIntent()
Return the associated with this preference.
Returns:
The last set via Preference.setIntent(Intent) or XML
public void
setFragment(java.lang.String fragment)
Sets the class name of a fragment to be shown when this preference is clicked.
Parameters:
fragment: The class name of the fragment associated with this preference
public java.lang.String
getFragment()
Return the fragment class name associated with this preference.
Returns:
The fragment class name last set via Preference.setFragment(String) or XML
Sets a PreferenceDataStore to be used by this preference instead of using
SharedPreferences
.
The data store will remain assigned even if the preference is moved around the preference
hierarchy. It will also override a data store propagated from the PreferenceManager
that owns this preference.
Parameters:
dataStore: The PreferenceDataStore to be used by this preference
See also: PreferenceManager.setPreferenceDataStore(PreferenceDataStore)
Returns PreferenceDataStore used by this preference. Returns null if
SharedPreferences
is used instead.
By default preferences always use SharedPreferences
. To make this
preference to use the PreferenceDataStore you need to assign your implementation
to the preference itself via Preference.setPreferenceDataStore(PreferenceDataStore) or to its
PreferenceManager via
PreferenceManager.setPreferenceDataStore(PreferenceDataStore).
Returns:
The PreferenceDataStore used by this preference or null if none
public Bundle
getExtras()
Return the extras Bundle object associated with this preference, creating a new Bundle if
there currently isn't one. You can use this to get and set individual extra key/value pairs.
public Bundle
peekExtras()
Return the extras Bundle object associated with this preference, returning null if
there is not currently one.
public void
setLayoutResource(int layoutResId)
Sets the layout resource that is inflated as the View
to be shown for this
preference. In most cases, the default layout is sufficient for custom preference objects
and only the widget layout needs to be changed.
This layout should contain a ViewGroup
with ID
to be the parent of the specific widget for this
preference. It should similarly contain and
.
It is an error to change the layout after adding the preference to a
PreferenceGroup.
Parameters:
layoutResId: The layout resource ID to be inflated and returned as a View
See also: Preference.setWidgetLayoutResource(int)
public final int
getLayoutResource()
Gets the layout resource that will be shown as the View
for this preference.
Returns:
The layout resource ID
public void
setWidgetLayoutResource(int widgetLayoutResId)
Sets the layout for the controllable widget portion of this preference. This is inflated
into the main layout. For example, a CheckBoxPreference would specify a custom
layout (consisting of just the CheckBox) here, instead of creating its own main layout.
It is an error to change the layout after adding the preference to a
PreferenceGroup.
Parameters:
widgetLayoutResId: The layout resource ID to be inflated into the main layout
See also: Preference.setLayoutResource(int)
public final int
getWidgetLayoutResource()
Gets the layout resource for the controllable widget portion of this preference.
Returns:
The layout resource ID
Binds the created View to the data for this preference.
This is a good place to grab references to custom Views in the layout and set
properties on them.
Make sure to call through to the superclass's implementation.
Parameters:
holder: The ViewHolder that provides references to the views to fill in. These views
will be recycled, so you should not hold a reference to them after this method
returns.
public void
setOrder(int order)
Sets the order of this preference with respect to other preference objects on the same
level. If this is not specified, the default behavior is to sort alphabetically. The
PreferenceGroup.setOrderingAsAdded(boolean) can be used to order preference
objects based on the order they appear in the XML.
Parameters:
order: The order for this preference. A lower value will be shown first. Use
Preference.DEFAULT_ORDER to sort alphabetically or allow ordering from XML.
See also: PreferenceGroup.setOrderingAsAdded(boolean), Preference.DEFAULT_ORDER
Gets the order of this preference with respect to other preference objects on the same level.
Returns:
The order of this preference
See also: Preference.setOrder(int)
public void
setViewId(int viewId)
Set the ID that will be assigned to the overall View representing this preference, once
bound.
See also: View
public void
setTitle(java.lang.CharSequence title)
Sets the title for this preference with a CharSequence. This title will be placed into the
ID within the View bound by
Preference.onBindViewHolder(PreferenceViewHolder).
Parameters:
title: The title for this preference
public void
setTitle(int titleResId)
Sets the title for this preference with a resource ID.
Parameters:
titleResId: The title as a resource ID
See also: Preference.setTitle(CharSequence)
public java.lang.CharSequence
getTitle()
Returns the title of this preference.
Returns:
The title
See also: Preference.setTitle(CharSequence)
public void
setIcon(Drawable icon)
Sets the icon for this preference with a Drawable. This icon will be placed into the ID
within the View created by
Preference.onBindViewHolder(PreferenceViewHolder).
Parameters:
icon: The optional icon for this preference
public Drawable
getIcon()
Returns the icon of this preference.
Returns:
The icon
See also: Preference.setIcon(Drawable)
public java.lang.CharSequence
getSummary()
Returns the summary of this preference. If a Preference.SummaryProvider has been set for this
preference, it will be used to provide the summary returned by this method.
Returns:
The summary
See also: Preference.setSummary(CharSequence), Preference.setSummaryProvider(Preference.SummaryProvider)
public void
setSummary(java.lang.CharSequence summary)
Sets the summary for this preference with a CharSequence.
You can also use a Preference.SummaryProvider to dynamically configure the summary of this
preference.
Parameters:
summary: The summary for the preference
See also: Preference.setSummaryProvider(Preference.SummaryProvider)
public void
setSummary(int summaryResId)
Sets the summary for this preference with a resource ID.
You can also use a Preference.SummaryProvider to dynamically configure the summary of this
preference.
Parameters:
summaryResId: The summary as a resource
See also: Preference.setSummary(CharSequence), Preference.setSummaryProvider(Preference.SummaryProvider)
public void
setEnabled(boolean enabled)
Sets whether this preference is enabled. If disabled, it will not handle clicks.
Parameters:
enabled: Set true to enable it
public boolean
isEnabled()
Checks whether this preference should be enabled in the list.
Returns:
true if this preference is enabled, false otherwise
public void
setSelectable(boolean selectable)
Sets whether this preference is selectable.
Parameters:
selectable: Set true to make it selectable
public boolean
isSelectable()
Checks whether this preference should be selectable in the list.
Returns:
true if it is selectable, false otherwise
public void
setShouldDisableView(boolean shouldDisableView)
Sets whether this preference should disable its view when it gets disabled.
For example, set this and Preference.setEnabled(boolean) to false for preferences that
are only displaying information and 1) should not be clickable 2) should not have the view
set to the disabled state.
Parameters:
shouldDisableView: Set true if this preference should disable its view when the
preference is disabled.
public boolean
getShouldDisableView()
Checks whether this preference should disable its view when it's action is disabled.
Returns:
true if it should disable the view
See also: Preference.setShouldDisableView(boolean)
public final void
setVisible(boolean visible)
Sets whether this preference should be visible to the user. If false, it is excluded from
the adapter, but can still be retrieved using
PreferenceFragmentCompat.findPreference(CharSequence).
To show this preference to the user, its ancestors must also all be visible. If you make
a PreferenceGroup invisible, none of its children will be shown to the user until
the group is visible.
Parameters:
visible: Set false if this preference should be hidden from the user
See also: Preference.isShown()
public final boolean
isVisible()
Checks whether this preference should be visible to the user.
If this preference is visible, but one or more of its ancestors are not visible, then this
preference will not be shown until its ancestors are all visible.
Returns:
true if this preference should be displayed
See also: Preference.setVisible(boolean), Preference.isShown()
public final boolean
isShown()
Checks whether this preference is shown to the user in the hierarchy.
For a preference to be shown in the hierarchy, it and all of its ancestors must be visible
and attached to the root PreferenceScreen.
Returns:
true if this preference is shown to the user in the hierarchy
Processes a click on the preference. This includes saving the value to
the SharedPreferences
. However, the overridden method should
call Preference.callChangeListener(Object) to make sure the client wants to
update the preference's state with the new value.
public void
setKey(java.lang.String key)
Sets the key for this preference, which is used as a key to the SharedPreferences
or
PreferenceDataStore. This should be unique for the package.
Parameters:
key: The key for the preference
public java.lang.String
getKey()
Gets the key for this preference, which is also the key used for storing values into
SharedPreferences
or PreferenceDataStore.
Returns:
The key
Checks whether this preference has a valid key.
Returns:
true if the key exists and is not a blank string, false otherwise
public boolean
isPersistent()
Checks whether this preference is persistent. If it is, it stores its value(s) into
the persistent SharedPreferences
storage by default or into
PreferenceDataStore if assigned.
Returns:
true if persistent
protected boolean
shouldPersist()
Checks whether, at the given time this method is called, this preference should store/restore
its value(s) into the SharedPreferences
or into PreferenceDataStore if
assigned. This, at minimum, checks whether this preference is persistent and it currently has
a key. Before you save/restore from the storage, check this first.
Returns:
true if it should persist the value
public void
setPersistent(boolean persistent)
Sets whether this preference is persistent. When persistent, it stores its value(s) into
the persistent SharedPreferences
storage by default or into
PreferenceDataStore if assigned.
Parameters:
persistent: Set true if it should store its value(s) into the storage
public void
setSingleLineTitle(boolean singleLineTitle)
Sets whether to constrain the title of this preference to a single line instead of
letting it wrap onto multiple lines.
Parameters:
singleLineTitle: Set true if the title should be constrained to one line
public boolean
isSingleLineTitle()
Gets whether the title of this preference is constrained to a single line.
Returns:
true if the title of this preference is constrained to a single line
See also: Preference.setSingleLineTitle(boolean)
public void
setIconSpaceReserved(boolean iconSpaceReserved)
Sets whether to reserve the space of this preference icon view when no icon is provided. If
set to true, the preference will be offset as if it would have the icon and thus aligned with
other preferences having icons.
Parameters:
iconSpaceReserved: Set true if the space for the icon view should be reserved
public boolean
isIconSpaceReserved()
Returns whether the space of this preference icon view is reserved.
Returns:
true if the space of this preference icon view is reserved
See also: Preference.setIconSpaceReserved(boolean)
public void
setCopyingEnabled(boolean enabled)
Sets whether the summary of this preference can be copied to the clipboard by
long pressing on the preference.
Parameters:
enabled: Set true to enable copying the summary of this preference
public boolean
isCopyingEnabled()
Returns whether the summary of this preference can be copied to the clipboard by
long pressing on the preference.
Returns:
true if copying is enabled, false otherwise
Set a Preference.SummaryProvider that will be invoked whenever the summary of this preference
is requested. Set null to remove the existing SummaryProvider.
Parameters:
summaryProvider: The Preference.SummaryProvider that will be invoked whenever the
summary of this preference is requested
See also: Preference.SummaryProvider
Returns the Preference.SummaryProvider used to configure the summary of this preference.
Returns:
The Preference.SummaryProvider used to configure the summary of this preference, or
null if there is no SummaryProvider set
See also: Preference.SummaryProvider
public boolean
callChangeListener(java.lang.Object newValue)
Call this method after the user changes the preference, but before the internal state is
set. This allows the client to ignore the user value.
Parameters:
newValue: The new value of this preference
Returns:
true if the user value should be set as the preference value (and persisted)
Sets the callback to be invoked when this preference is changed by the user (but before
the internal state has been updated).
Parameters:
onPreferenceChangeListener: The callback to be invoked
Returns the callback to be invoked when this preference is changed by the user (but before
the internal state has been updated).
Returns:
The callback to be invoked
Sets the callback to be invoked when this preference is clicked.
Parameters:
onPreferenceClickListener: The callback to be invoked
Returns the callback to be invoked when this preference is clicked.
Returns:
The callback to be invoked
protected void
performClick(View view)
Used by Settings.
public void
performClick()
Called when a click should be performed.
Used by Settings.
public Context
getContext()
Returns the of this preference.
Each preference in a preference hierarchy can be from different Context (for example, if
multiple activities provide preferences into a single PreferenceFragmentCompat).
This Context will be used to save the preference values.
Returns:
The Context of this preference
public SharedPreferences
getSharedPreferences()
Returns the SharedPreferences
where this preference can read its
value(s). Usually, it's easier to use one of the helper read methods:
Preference.getPersistedBoolean(boolean), Preference.getPersistedFloat(float),
Preference.getPersistedInt(int), Preference.getPersistedLong(long),
Preference.getPersistedString(String).
Returns:
The SharedPreferences
where this preference reads its value(s). If this
preference is not attached to a preference hierarchy or if a
PreferenceDataStore has been set, this method returns null.
See also: Preference.setPreferenceDataStore(PreferenceDataStore)
Compares preference objects based on order (if set), otherwise alphabetically on the titles.
Parameters:
another: The preference to compare to this one
Returns:
0 if the same; less than 0 if this preference sorts ahead of another;
greater than 0 if this preference sorts after another.
protected void
notifyChanged()
Should be called when the data of this Preference has changed.
protected void
notifyHierarchyChanged()
Should be called when a preference has been added/removed from this group, or the ordering
should be re-evaluated.
Gets the PreferenceManager that manages this preference object's tree.
Returns:
The PreferenceManager
Called when this preference has been attached to a preference hierarchy. Make sure to call
the super implementation.
Parameters:
preferenceManager: The PreferenceManager of the hierarchy
Called from PreferenceGroup to pass in an ID for reuse.
Used by Settings.
Called when the preference hierarchy has been attached to the list of preferences. This
can also be called when this preference has been attached to a group that was already
attached to the list of preferences.
Called when the preference hierarchy has been detached from the list of preferences. This
can also be called when this preference has been removed from a group that was attached to
the list of preferences.
protected
Preference findPreferenceInHierarchy(java.lang.String key)
Finds a preference in the entire hierarchy (above or below this preference) with the given
key. Returns null if no preference could be found with the given key.
This only works after this preference has been attached to a hierarchy.
Parameters:
key: The key of the preference to retrieve
Returns:
The preference with the key, or null
See also: PreferenceGroup.findPreference(CharSequence)
public void
notifyDependencyChange(boolean disableDependents)
Notifies any listening dependents of a change that affects the dependency.
Parameters:
disableDependents: Whether this preference should disable
its dependents.
public void
onDependencyChanged(
Preference dependency, boolean disableDependent)
Called when the dependency changes.
Parameters:
dependency: The preference that this preference depends on
disableDependent: Set true to disable this preference
public void
onParentChanged(
Preference parent, boolean disableChild)
Called when the implicit parent dependency changes.
Parameters:
parent: The preference that this preference depends on
disableChild: Set true to disable this preference
public boolean
shouldDisableDependents()
Checks whether this preference's dependents should currently be disabled.
Returns:
true if the dependents should be disabled, otherwise false
public void
setDependency(java.lang.String dependencyKey)
Sets the key of a preference that this preference will depend on. If that preference is
not set or is off, this preference will be disabled.
Parameters:
dependencyKey: The key of the preference that this depends on
public java.lang.String
getDependency()
Returns the key of the dependency on this preference.
Returns:
The key of the dependency
See also: Preference.setDependency(String)
Returns the PreferenceGroup which is this preference assigned to or null
if this preference is not assigned to any group or is a root preference.
Returns:
The parent PreferenceGroup or null if not attached to any
protected void
onPrepareForRemoval()
Called when this preference is being removed from the hierarchy. You should remove any
references to this preference that you know about. Make sure to call through to the
superclass implementation.
public void
setDefaultValue(java.lang.Object defaultValue)
Sets the default value for this preference, which will be set either if persistence is off
or persistence is on and the preference is not found in the persistent storage.
Parameters:
defaultValue: The default value
protected void
onSetInitialValue(boolean restorePersistedValue, java.lang.Object defaultValue)
Deprecated: Use Preference.onSetInitialValue(Object) instead.
Implement this to set the initial value of the preference.
If restorePersistedValue is true, you should restore the preference value
from the SharedPreferences
. If restorePersistedValue is
false, you should set the preference value to defaultValue that is given (and possibly
store to SharedPreferences if Preference.shouldPersist() is true).
In case of using PreferenceDataStore, the restorePersistedValue is
always true but the default value (if provided) is set.
This may not always be called. One example is if it should not persist but there is no
default value given.
Parameters:
restorePersistedValue: True to restore the persisted value;
false to use the given defaultValue.
defaultValue: The default value for this preference. Only use this
if restorePersistedValue is false.
protected void
onSetInitialValue(java.lang.Object defaultValue)
Implement this to set the initial value of the preference.
If you are persisting values to SharedPreferences
or a PreferenceDataStore
you should restore the saved value for the preference.
If you are not persisting values, or there is no value saved for the preference, you
should set the value of the preference to defaultValue.
Parameters:
defaultValue: The default value for the preference if set, otherwise null.
protected boolean
persistString(java.lang.String value)
Attempts to persist a java.lang.String
if this preference is persistent.
The returned value doesn't reflect whether the given value was persisted, since we may not
necessarily commit if there will be a batch commit later.
Parameters:
value: The value to persist
Returns:
true if the preference is persistent, false otherwise
See also: Preference.getPersistedString(String)
protected java.lang.String
getPersistedString(java.lang.String defaultReturnValue)
Attempts to get a persisted set of Strings if this preference is persistent.
Parameters:
defaultReturnValue: The default value to return if either the preference is not
persistent or the preference is not in the shared preferences.
Returns:
The value from the storage or the default return value
See also: Preference.persistString(String)
public boolean
persistStringSet(java.util.Set<java.lang.String> values)
Attempts to persist a set of Strings if this preference is persistent.
The returned value doesn't reflect whether the given value was persisted, since we may not
necessarily commit if there will be a batch commit later.
Parameters:
values: The values to persist
Returns:
true if the preference is persistent, false otherwise
See also: Preference.getPersistedStringSet(Set)
public java.util.Set<java.lang.String>
getPersistedStringSet(java.util.Set<java.lang.String> defaultReturnValue)
Attempts to get a persisted set of Strings if this preference is persistent.
Parameters:
defaultReturnValue: The default value to return if either this preference is not
persistent or this preference is not present.
Returns:
The value from the storage or the default return value
See also: Preference.persistStringSet(Set)
protected boolean
persistInt(int value)
Attempts to persist an java.lang.Integer
if this preference is persistent.
The returned value doesn't reflect whether the given value was persisted, since we may not
necessarily commit if there will be a batch commit later.
Parameters:
value: The value to persist
Returns:
true if the preference is persistent, false otherwise
See also: Preference.persistString(String), Preference.getPersistedInt(int)
protected int
getPersistedInt(int defaultReturnValue)
Attempts to get a persisted java.lang.Integer
if this preference is persistent.
Parameters:
defaultReturnValue: The default value to return if either this preference is not
persistent or this preference is not in the SharedPreferences.
Returns:
The value from the storage or the default return value
See also: Preference.getPersistedString(String), Preference.persistInt(int)
protected boolean
persistFloat(float value)
Attempts to persist a java.lang.Float
if this preference is persistent.
The returned value doesn't reflect whether the given value was persisted, since we may not
necessarily commit if there will be a batch commit later.
Parameters:
value: The value to persist
Returns:
true if the preference is persistent, false otherwise
See also: Preference.persistString(String), Preference.getPersistedFloat(float)
protected float
getPersistedFloat(float defaultReturnValue)
Attempts to get a persisted java.lang.Float
if this preference is persistent.
Parameters:
defaultReturnValue: The default value to return if either this preference is not
persistent or this preference is not saved.
Returns:
The value from the storage or the default return value
See also: Preference.getPersistedString(String), Preference.persistFloat(float)
protected boolean
persistLong(long value)
Attempts to persist a java.lang.Long
if this preference is persistent.
The returned value doesn't reflect whether the given value was persisted, since we may not
necessarily commit if there will be a batch commit later.
Parameters:
value: The value to persist
Returns:
true if the preference is persistent, false otherwise
See also: Preference.persistString(String), Preference.getPersistedLong(long)
protected long
getPersistedLong(long defaultReturnValue)
Attempts to get a persisted java.lang.Long
if this preference is persistent.
Parameters:
defaultReturnValue: The default value to return if either this preference is not
persistent or this preference is not in the SharedPreferences.
Returns:
The value from the storage or the default return value
See also: Preference.getPersistedString(String), Preference.persistLong(long)
protected boolean
persistBoolean(boolean value)
Attempts to persist a java.lang.Boolean
if this preference is persistent.
The returned value doesn't reflect whether the given value was persisted, since we may not
necessarily commit if there will be a batch commit later.
Parameters:
value: The value to persist
Returns:
true if the preference is persistent, false otherwise
See also: Preference.persistString(String), Preference.getPersistedBoolean(boolean)
protected boolean
getPersistedBoolean(boolean defaultReturnValue)
Attempts to get a persisted java.lang.Boolean
if this preference is persistent.
Parameters:
defaultReturnValue: The default value to return if either this preference is not
persistent or this preference is not in the SharedPreferences.
Returns:
The value from the storage or the default return value
See also: Preference.getPersistedString(String), Preference.persistBoolean(boolean)
public java.lang.String
toString()
public void
saveHierarchyState(Bundle container)
Store this preference hierarchy's frozen state into the given container.
Parameters:
container: The Bundle in which to save the instance of this preference
See also: Preference.restoreHierarchyState(Bundle), Preference.onSaveInstanceState()
protected Parcelable
onSaveInstanceState()
Hook allowing a preference to generate a representation of its internal state that can
later be used to create a new instance with that same state. This state should only
contain information that is not persistent or can be reconstructed later.
Returns:
A Parcelable object containing the current dynamic state of this preference, or
null if there is nothing interesting to save. The default implementation returns
null.
See also: Preference.onRestoreInstanceState(Parcelable), Preference.saveHierarchyState(Bundle)
public void
restoreHierarchyState(Bundle container)
Restore this preference hierarchy's previously saved state from the given container.
Parameters:
container: The Bundle that holds the previously saved state
See also: Preference.saveHierarchyState(Bundle), Preference.onRestoreInstanceState(Parcelable)
protected void
onRestoreInstanceState(Parcelable state)
Hook allowing a preference to re-apply a representation of its internal state that had
previously been generated by Preference.onSaveInstanceState(). This function will never be
called with a null state.
Parameters:
state: The saved state that had previously been returned by
Preference.onSaveInstanceState().
See also: Preference.onSaveInstanceState(), Preference.restoreHierarchyState(Bundle)
Deprecated: Preferences aren't views. They should not need any accessibility changes,
unless the view hierarchy is customized. In this situation, please add Accessibility
information in Preference.onBindViewHolder(PreferenceViewHolder).
Initializes an android.view.accessibility.AccessibilityNodeInfo
with information
about the View for this preference.
Source
/*
* Copyright 2018 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package androidx.preference;
import static androidx.annotation.RestrictTo.Scope.LIBRARY_GROUP_PREFIX;
import android.content.ClipData;
import android.content.ClipboardManager;
import android.content.Context;
import android.content.Intent;
import android.content.SharedPreferences;
import android.content.res.TypedArray;
import android.graphics.drawable.Drawable;
import android.os.Bundle;
import android.os.Parcel;
import android.os.Parcelable;
import android.text.TextUtils;
import android.util.AttributeSet;
import android.view.AbsSavedState;
import android.view.ContextMenu;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ImageView;
import android.widget.TextView;
import android.widget.Toast;
import androidx.annotation.CallSuper;
import androidx.annotation.NonNull;
import androidx.annotation.Nullable;
import androidx.annotation.RestrictTo;
import androidx.appcompat.content.res.AppCompatResources;
import androidx.core.content.res.TypedArrayUtils;
import androidx.core.view.ViewCompat;
import androidx.core.view.accessibility.AccessibilityNodeInfoCompat;
import java.util.ArrayList;
import java.util.List;
import java.util.Set;
/**
* The basic building block that represents an individual setting displayed to a user in the
* preference hierarchy. This class provides the data that will be displayed to the user and has
* a reference to the {@link SharedPreferences} or {@link PreferenceDataStore} instance that
* persists the preference's values.
*
* <p>When specifying a preference hierarchy in XML, each element can point to a subclass of
* {@link Preference}, similar to the view hierarchy and layouts.
*
* <p>This class contains a {@code key} that that represents the key that is used to persist the
* value to the device. It is up to the subclass to decide how to store the value.
*
* <div class="special reference">
* <h3>Developer Guides</h3>
* <p>For information about building a settings screen using the AndroidX Preference library, see
* <a href="{@docRoot}guide/topics/ui/settings.html">Settings</a>.</p>
* </div>
*
* @attr name android:icon
* @attr name android:key
* @attr name android:title
* @attr name android:summary
* @attr name android:order
* @attr name android:fragment
* @attr name android:layout
* @attr name android:widgetLayout
* @attr name android:enabled
* @attr name android:selectable
* @attr name android:dependency
* @attr name android:persistent
* @attr name android:defaultValue
* @attr name android:shouldDisableView
* @attr name android:singleLineTitle
* @attr name android:iconSpaceReserved
*/
public class Preference implements Comparable<Preference> {
/**
* Specify for {@link #setOrder(int)} if a specific order is not required.
*/
public static final int DEFAULT_ORDER = Integer.MAX_VALUE;
private static final String CLIPBOARD_ID = "Preference";
@NonNull
private final Context mContext;
@Nullable
private PreferenceManager mPreferenceManager;
/**
* The data store that should be used by this preference to store / retrieve data. If {@code
* null} then {@link PreferenceManager#getPreferenceDataStore()} needs to be checked. If that
* one is {@code null} too it means that we are using {@link SharedPreferences} to store the
* data.
*/
@Nullable
private PreferenceDataStore mPreferenceDataStore;
/**
* Set when added to hierarchy since we need a unique ID within that hierarchy.
*/
private long mId;
/**
* Set true temporarily to keep {@link #onAttachedToHierarchy(PreferenceManager)} from
* overwriting mId.
*/
private boolean mHasId;
private OnPreferenceChangeListener mOnChangeListener;
private OnPreferenceClickListener mOnClickListener;
private int mOrder = DEFAULT_ORDER;
private int mViewId = 0;
private CharSequence mTitle;
private CharSequence mSummary;
/**
* mIconResId is overridden by mIcon, if mIcon is specified.
*/
private int mIconResId;
private Drawable mIcon;
private String mKey;
private Intent mIntent;
private String mFragment;
private Bundle mExtras;
private boolean mEnabled = true;
private boolean mSelectable = true;
private boolean mRequiresKey;
private boolean mPersistent = true;
private String mDependencyKey;
private Object mDefaultValue;
private boolean mDependencyMet = true;
private boolean mParentDependencyMet = true;
private boolean mVisible = true;
private boolean mAllowDividerAbove = true;
private boolean mAllowDividerBelow = true;
private boolean mHasSingleLineTitleAttr;
private boolean mSingleLineTitle = true;
private boolean mIconSpaceReserved;
private boolean mCopyingEnabled;
/**
* @see #setShouldDisableView(boolean)
*/
private boolean mShouldDisableView = true;
private int mLayoutResId = R.layout.preference;
private int mWidgetLayoutResId;
private OnPreferenceChangeInternalListener mListener;
private List<Preference> mDependents;
private PreferenceGroup mParentGroup;
private boolean mWasDetached;
private boolean mBaseMethodCalled;
private OnPreferenceCopyListener mOnCopyListener;
private SummaryProvider mSummaryProvider;
private final View.OnClickListener mClickListener = new View.OnClickListener() {
@Override
public void onClick(View v) {
performClick(v);
}
};
/**
* Perform inflation from XML and apply a class-specific base style. This constructor allows
* subclasses to use their own base style when they are inflating. For example, a
* {@link CheckBoxPreference} constructor calls this version of the super class constructor
* and supplies {@code android.R.attr.checkBoxPreferenceStyle} for <var>defStyleAttr</var>.
* This allows the theme's checkbox preference style to modify all of the base preference
* attributes as well as the {@link CheckBoxPreference} class's attributes.
*
* @param context The {@link Context} this is associated with, through which it can
* access the current theme, resources, {@link SharedPreferences}, etc.
* @param attrs The attributes of the XML tag that is inflating the preference
* @param defStyleAttr An attribute in the current theme that contains a reference to a style
* resource that supplies default values for the view. Can be 0 to not
* look for defaults.
* @param defStyleRes A resource identifier of a style resource that supplies default values
* for the view, used only if defStyleAttr is 0 or can not be found in the
* theme. Can be 0 to not look for defaults.
* @see #Preference(Context, android.util.AttributeSet)
*/
public Preference(@NonNull Context context, @Nullable AttributeSet attrs, int defStyleAttr,
int defStyleRes) {
mContext = context;
final TypedArray a = context.obtainStyledAttributes(
attrs, R.styleable.Preference, defStyleAttr, defStyleRes);
mIconResId = TypedArrayUtils.getResourceId(a, R.styleable.Preference_icon,
R.styleable.Preference_android_icon, 0);
mKey = TypedArrayUtils.getString(a, R.styleable.Preference_key,
R.styleable.Preference_android_key);
mTitle = TypedArrayUtils.getText(a, R.styleable.Preference_title,
R.styleable.Preference_android_title);
mSummary = TypedArrayUtils.getText(a, R.styleable.Preference_summary,
R.styleable.Preference_android_summary);
mOrder = TypedArrayUtils.getInt(a, R.styleable.Preference_order,
R.styleable.Preference_android_order, DEFAULT_ORDER);
mFragment = TypedArrayUtils.getString(a, R.styleable.Preference_fragment,
R.styleable.Preference_android_fragment);
mLayoutResId = TypedArrayUtils.getResourceId(a, R.styleable.Preference_layout,
R.styleable.Preference_android_layout, R.layout.preference);
mWidgetLayoutResId = TypedArrayUtils.getResourceId(a, R.styleable.Preference_widgetLayout,
R.styleable.Preference_android_widgetLayout, 0);
mEnabled = TypedArrayUtils.getBoolean(a, R.styleable.Preference_enabled,
R.styleable.Preference_android_enabled, true);
mSelectable = TypedArrayUtils.getBoolean(a, R.styleable.Preference_selectable,
R.styleable.Preference_android_selectable, true);
mPersistent = TypedArrayUtils.getBoolean(a, R.styleable.Preference_persistent,
R.styleable.Preference_android_persistent, true);
mDependencyKey = TypedArrayUtils.getString(a, R.styleable.Preference_dependency,
R.styleable.Preference_android_dependency);
mAllowDividerAbove = TypedArrayUtils.getBoolean(a, R.styleable.Preference_allowDividerAbove,
R.styleable.Preference_allowDividerAbove, mSelectable);
mAllowDividerBelow = TypedArrayUtils.getBoolean(a, R.styleable.Preference_allowDividerBelow,
R.styleable.Preference_allowDividerBelow, mSelectable);
if (a.hasValue(R.styleable.Preference_defaultValue)) {
mDefaultValue = onGetDefaultValue(a, R.styleable.Preference_defaultValue);
} else if (a.hasValue(R.styleable.Preference_android_defaultValue)) {
mDefaultValue = onGetDefaultValue(a, R.styleable.Preference_android_defaultValue);
}
mShouldDisableView =
TypedArrayUtils.getBoolean(a, R.styleable.Preference_shouldDisableView,
R.styleable.Preference_android_shouldDisableView, true);
mHasSingleLineTitleAttr = a.hasValue(R.styleable.Preference_singleLineTitle);
if (mHasSingleLineTitleAttr) {
mSingleLineTitle = TypedArrayUtils.getBoolean(a, R.styleable.Preference_singleLineTitle,
R.styleable.Preference_android_singleLineTitle, true);
}
mIconSpaceReserved = TypedArrayUtils.getBoolean(a, R.styleable.Preference_iconSpaceReserved,
R.styleable.Preference_android_iconSpaceReserved, false);
mVisible = TypedArrayUtils.getBoolean(a, R.styleable.Preference_isPreferenceVisible,
R.styleable.Preference_isPreferenceVisible, true);
mCopyingEnabled = TypedArrayUtils.getBoolean(a, R.styleable.Preference_enableCopying,
R.styleable.Preference_enableCopying, false);
a.recycle();
}
/**
* Perform inflation from XML and apply a class-specific base style. This constructor allows
* subclasses to use their own base style when they are inflating. For example, a
* {@link CheckBoxPreference} constructor calls this version of the super class constructor
* and supplies {@code android.R.attr.checkBoxPreferenceStyle} for <var>defStyleAttr</var>.
* This allows the theme's checkbox preference style to modify all of the base preference
* attributes as well as the {@link CheckBoxPreference} class's attributes.
*
* @param context The Context this is associated with, through which it can access the
* current theme, resources, {@link SharedPreferences}, etc.
* @param attrs The attributes of the XML tag that is inflating the preference
* @param defStyleAttr An attribute in the current theme that contains a reference to a style
* resource that supplies default values for the view. Can be 0 to not
* look for defaults.
* @see #Preference(Context, AttributeSet)
*/
public Preference(@NonNull Context context, @Nullable AttributeSet attrs, int defStyleAttr) {
this(context, attrs, defStyleAttr, 0);
}
/**
* Constructor that is called when inflating a preference from XML. This is called when a
* preference is being constructed from an XML file, supplying attributes that were specified
* in the XML file. This version uses a default style of 0, so the only attribute values
* applied are those in the Context's Theme and the given AttributeSet.
*
* @param context The Context this is associated with, through which it can access the
* current theme, resources, {@link SharedPreferences}, etc.
* @param attrs The attributes of the XML tag that is inflating the preference
* @see #Preference(Context, AttributeSet, int)
*/
public Preference(@NonNull Context context, @Nullable AttributeSet attrs) {
this(context, attrs, TypedArrayUtils.getAttr(context, R.attr.preferenceStyle,
android.R.attr.preferenceStyle));
}
/**
* Constructor to create a preference.
*
* @param context The Context this is associated with, through which it can access the
* current theme, resources, {@link SharedPreferences}, etc.
*/
public Preference(@NonNull Context context) {
this(context, null);
}
/**
* Called when a preference is being inflated and the default value attribute needs to be
* read. Since different preference types have different value types, the subclass should get
* and return the default value which will be its value type.
*
* <p>For example, if the value type is String, the body of the method would proxy to
* {@link TypedArray#getString(int)}.
*
* @param a The set of attributes
* @param index The index of the default value attribute
* @return The default value of this preference type
*/
@Nullable
protected Object onGetDefaultValue(@NonNull TypedArray a, int index) {
return null;
}
/**
* Sets an {@link Intent} to be used for {@link Context#startActivity(Intent)} when this
* preference is clicked.
*
* @param intent The intent associated with this preference
*/
public void setIntent(@Nullable Intent intent) {
mIntent = intent;
}
/**
* Return the {@link Intent} associated with this preference.
*
* @return The {@link Intent} last set via {@link #setIntent(Intent)} or XML
*/
@Nullable
public Intent getIntent() {
return mIntent;
}
/**
* Sets the class name of a fragment to be shown when this preference is clicked.
*
* @param fragment The class name of the fragment associated with this preference
*/
public void setFragment(@Nullable String fragment) {
mFragment = fragment;
}
/**
* Return the fragment class name associated with this preference.
*
* @return The fragment class name last set via {@link #setFragment} or XML
*/
@Nullable
public String getFragment() {
return mFragment;
}
/**
* Sets a {@link PreferenceDataStore} to be used by this preference instead of using
* {@link SharedPreferences}.
*
* <p>The data store will remain assigned even if the preference is moved around the preference
* hierarchy. It will also override a data store propagated from the {@link PreferenceManager}
* that owns this preference.
*
* @param dataStore The {@link PreferenceDataStore} to be used by this preference
* @see PreferenceManager#setPreferenceDataStore(PreferenceDataStore)
*/
public void setPreferenceDataStore(@Nullable PreferenceDataStore dataStore) {
mPreferenceDataStore = dataStore;
}
/**
* Returns {@link PreferenceDataStore} used by this preference. Returns {@code null} if
* {@link SharedPreferences} is used instead.
*
* <p>By default preferences always use {@link SharedPreferences}. To make this
* preference to use the {@link PreferenceDataStore} you need to assign your implementation
* to the preference itself via {@link #setPreferenceDataStore(PreferenceDataStore)} or to its
* {@link PreferenceManager} via
* {@link PreferenceManager#setPreferenceDataStore(PreferenceDataStore)}.
*
* @return The {@link PreferenceDataStore} used by this preference or {@code null} if none
*/
@Nullable
public PreferenceDataStore getPreferenceDataStore() {
if (mPreferenceDataStore != null) {
return mPreferenceDataStore;
} else if (mPreferenceManager != null) {
return mPreferenceManager.getPreferenceDataStore();
}
return null;
}
/**
* Return the extras Bundle object associated with this preference, creating a new Bundle if
* there currently isn't one. You can use this to get and set individual extra key/value pairs.
*/
@NonNull
public Bundle getExtras() {
if (mExtras == null) {
mExtras = new Bundle();
}
return mExtras;
}
/**
* Return the extras Bundle object associated with this preference, returning {@code null} if
* there is not currently one.
*/
@SuppressWarnings("NullableCollection")
@Nullable
public Bundle peekExtras() {
return mExtras;
}
/**
* Sets the layout resource that is inflated as the {@link View} to be shown for this
* preference. In most cases, the default layout is sufficient for custom preference objects
* and only the widget layout needs to be changed.
*
* <p>This layout should contain a {@link ViewGroup} with ID
* {@link android.R.id#widget_frame} to be the parent of the specific widget for this
* preference. It should similarly contain {@link android.R.id#title} and
* {@link android.R.id#summary}.
*
* <p>It is an error to change the layout after adding the preference to a
* {@link PreferenceGroup}.
*
* @param layoutResId The layout resource ID to be inflated and returned as a {@link View}
* @see #setWidgetLayoutResource(int)
*/
public void setLayoutResource(int layoutResId) {
mLayoutResId = layoutResId;
}
/**
* Gets the layout resource that will be shown as the {@link View} for this preference.
*
* @return The layout resource ID
*/
public final int getLayoutResource() {
return mLayoutResId;
}
/**
* Sets the layout for the controllable widget portion of this preference. This is inflated
* into the main layout. For example, a {@link CheckBoxPreference} would specify a custom
* layout (consisting of just the CheckBox) here, instead of creating its own main layout.
*
* <p>It is an error to change the layout after adding the preference to a
* {@link PreferenceGroup}.
*
* @param widgetLayoutResId The layout resource ID to be inflated into the main layout
* @see #setLayoutResource(int)
*/
public void setWidgetLayoutResource(int widgetLayoutResId) {
mWidgetLayoutResId = widgetLayoutResId;
}
/**
* Gets the layout resource for the controllable widget portion of this preference.
*
* @return The layout resource ID
*/
public final int getWidgetLayoutResource() {
return mWidgetLayoutResId;
}
/**
* Binds the created View to the data for this preference.
*
* <p>This is a good place to grab references to custom Views in the layout and set
* properties on them.
*
* <p>Make sure to call through to the superclass's implementation.
*
* @param holder The ViewHolder that provides references to the views to fill in. These views
* will be recycled, so you should not hold a reference to them after this method
* returns.
*/
public void onBindViewHolder(@NonNull PreferenceViewHolder holder) {
View itemView = holder.itemView;
Integer summaryTextColor = null;
itemView.setOnClickListener(mClickListener);
itemView.setId(mViewId);
final TextView summaryView = (TextView) holder.findViewById(android.R.id.summary);
if (summaryView != null) {
final CharSequence summary = getSummary();
if (!TextUtils.isEmpty(summary)) {
summaryView.setText(summary);
summaryView.setVisibility(View.VISIBLE);
summaryTextColor = summaryView.getCurrentTextColor();
} else {
summaryView.setVisibility(View.GONE);
}
}
final TextView titleView = (TextView) holder.findViewById(android.R.id.title);
if (titleView != null) {
final CharSequence title = getTitle();
if (!TextUtils.isEmpty(title)) {
titleView.setText(title);
titleView.setVisibility(View.VISIBLE);
if (mHasSingleLineTitleAttr) {
titleView.setSingleLine(mSingleLineTitle);
}
// If this Preference is not selectable, but still enabled, we should set the
// title text colour to the same colour used for the summary text
if (!isSelectable() && isEnabled() && summaryTextColor != null) {
titleView.setTextColor(summaryTextColor);
}
} else {
titleView.setVisibility(View.GONE);
}
}
final ImageView imageView = (ImageView) holder.findViewById(android.R.id.icon);
if (imageView != null) {
if (mIconResId != 0 || mIcon != null) {
if (mIcon == null) {
mIcon = AppCompatResources.getDrawable(mContext, mIconResId);
}
if (mIcon != null) {
imageView.setImageDrawable(mIcon);
}
}
if (mIcon != null) {
imageView.setVisibility(View.VISIBLE);
} else {
imageView.setVisibility(mIconSpaceReserved ? View.INVISIBLE : View.GONE);
}
}
View imageFrame = holder.findViewById(R.id.icon_frame);
if (imageFrame == null) {
imageFrame = holder.findViewById(AndroidResources.ANDROID_R_ICON_FRAME);
}
if (imageFrame != null) {
if (mIcon != null) {
imageFrame.setVisibility(View.VISIBLE);
} else {
imageFrame.setVisibility(mIconSpaceReserved ? View.INVISIBLE : View.GONE);
}
}
if (mShouldDisableView) {
setEnabledStateOnViews(itemView, isEnabled());
} else {
setEnabledStateOnViews(itemView, true);
}
final boolean selectable = isSelectable();
itemView.setFocusable(selectable);
itemView.setClickable(selectable);
holder.setDividerAllowedAbove(mAllowDividerAbove);
holder.setDividerAllowedBelow(mAllowDividerBelow);
final boolean copyingEnabled = isCopyingEnabled();
if (copyingEnabled && mOnCopyListener == null) {
mOnCopyListener = new OnPreferenceCopyListener(this);
}
itemView.setOnCreateContextMenuListener(copyingEnabled ? mOnCopyListener : null);
itemView.setLongClickable(copyingEnabled);
// Remove touch ripple if copying is enabled and the view isn't selectable. This is
// needed as enabling copying requires the view to be `clickable`, but we only care about
// long clicks, and not normal clicks.
if (copyingEnabled && !selectable) {
ViewCompat.setBackground(itemView, null);
}
}
/**
* Makes sure the view (and any children) get the enabled state changed.
*/
private void setEnabledStateOnViews(@NonNull View v, boolean enabled) {
v.setEnabled(enabled);
if (v instanceof ViewGroup) {
final ViewGroup vg = (ViewGroup) v;
for (int i = vg.getChildCount() - 1; i >= 0; i--) {
setEnabledStateOnViews(vg.getChildAt(i), enabled);
}
}
}
/**
* Sets the order of this preference with respect to other preference objects on the same
* level. If this is not specified, the default behavior is to sort alphabetically. The
* {@link PreferenceGroup#setOrderingAsAdded(boolean)} can be used to order preference
* objects based on the order they appear in the XML.
*
* @param order The order for this preference. A lower value will be shown first. Use
* {@link #DEFAULT_ORDER} to sort alphabetically or allow ordering from XML.
* @see PreferenceGroup#setOrderingAsAdded(boolean)
* @see #DEFAULT_ORDER
*/
public void setOrder(int order) {
if (order != mOrder) {
mOrder = order;
// Reorder the list
notifyHierarchyChanged();
}
}
/**
* Gets the order of this preference with respect to other preference objects on the same level.
*
* @return The order of this preference
* @see #setOrder(int)
*/
public int getOrder() {
return mOrder;
}
/**
* Set the ID that will be assigned to the overall View representing this preference, once
* bound.
*
* @see View#setId(int)
*/
public void setViewId(int viewId) {
mViewId = viewId;
}
/**
* Sets the title for this preference with a CharSequence. This title will be placed into the
* ID {@link android.R.id#title} within the View bound by
* {@link #onBindViewHolder(PreferenceViewHolder)}.
*
* @param title The title for this preference
*/
public void setTitle(@Nullable CharSequence title) {
if (!TextUtils.equals(title, mTitle)) {
mTitle = title;
notifyChanged();
}
}
/**
* Sets the title for this preference with a resource ID.
*
* @param titleResId The title as a resource ID
* @see #setTitle(CharSequence)
*/
public void setTitle(int titleResId) {
setTitle(mContext.getString(titleResId));
}
/**
* Returns the title of this preference.
*
* @return The title
* @see #setTitle(CharSequence)
*/
@Nullable
public CharSequence getTitle() {
return mTitle;
}
/**
* Sets the icon for this preference with a Drawable. This icon will be placed into the ID
* {@link android.R.id#icon} within the View created by
* {@link #onBindViewHolder(PreferenceViewHolder)}.
*
* @param icon The optional icon for this preference
*/
public void setIcon(@Nullable Drawable icon) {
if (mIcon != icon) {
mIcon = icon;
mIconResId = 0;
notifyChanged();
}
}
/**
* Sets the icon for this preference with a resource ID.
*
* @param iconResId The icon as a resource ID
* @see #setIcon(Drawable)
*/
public void setIcon(int iconResId) {
setIcon(AppCompatResources.getDrawable(mContext, iconResId));
mIconResId = iconResId;
}
/**
* Returns the icon of this preference.
*
* @return The icon
* @see #setIcon(Drawable)
*/
@Nullable
public Drawable getIcon() {
if (mIcon == null && mIconResId != 0) {
mIcon = AppCompatResources.getDrawable(mContext, mIconResId);
}
return mIcon;
}
/**
* Returns the summary of this preference. If a {@link SummaryProvider} has been set for this
* preference, it will be used to provide the summary returned by this method.
*
* @return The summary
* @see #setSummary(CharSequence)
* @see #setSummaryProvider(SummaryProvider)
*/
@Nullable
@SuppressWarnings("unchecked")
public CharSequence getSummary() {
if (getSummaryProvider() != null) {
return getSummaryProvider().provideSummary(this);
}
return mSummary;
}
/**
* Sets the summary for this preference with a CharSequence.
*
* <p>You can also use a {@link SummaryProvider} to dynamically configure the summary of this
* preference.
*
* @param summary The summary for the preference
* @throws IllegalStateException If a {@link SummaryProvider} has already been set.
* @see #setSummaryProvider(SummaryProvider)
*/
public void setSummary(@Nullable CharSequence summary) {
if (getSummaryProvider() != null) {
throw new IllegalStateException("Preference already has a SummaryProvider set.");
}
if (!TextUtils.equals(mSummary, summary)) {
mSummary = summary;
notifyChanged();
}
}
/**
* Sets the summary for this preference with a resource ID.
*
* <p>You can also use a {@link SummaryProvider} to dynamically configure the summary of this
* preference.
*
* @param summaryResId The summary as a resource
* @see #setSummary(CharSequence)
* @see #setSummaryProvider(SummaryProvider)
*/
public void setSummary(int summaryResId) {
setSummary(mContext.getString(summaryResId));
}
/**
* Sets whether this preference is enabled. If disabled, it will not handle clicks.
*
* @param enabled Set true to enable it
*/
public void setEnabled(boolean enabled) {
if (mEnabled != enabled) {
mEnabled = enabled;
// Enabled state can change dependent preferences' states, so notify
notifyDependencyChange(shouldDisableDependents());
notifyChanged();
}
}
/**
* Checks whether this preference should be enabled in the list.
*
* @return {@code true} if this preference is enabled, false otherwise
*/
public boolean isEnabled() {
return mEnabled && mDependencyMet && mParentDependencyMet;
}
/**
* Sets whether this preference is selectable.
*
* @param selectable Set true to make it selectable
*/
public void setSelectable(boolean selectable) {
if (mSelectable != selectable) {
mSelectable = selectable;
notifyChanged();
}
}
/**
* Checks whether this preference should be selectable in the list.
*
* @return {@code true} if it is selectable, false otherwise
*/
public boolean isSelectable() {
return mSelectable;
}
/**
* Sets whether this preference should disable its view when it gets disabled.
*
* <p>For example, set this and {@link #setEnabled(boolean)} to false for preferences that
* are only displaying information and 1) should not be clickable 2) should not have the view
* set to the disabled state.
*
* @param shouldDisableView Set true if this preference should disable its view when the
* preference is disabled.
*/
public void setShouldDisableView(boolean shouldDisableView) {
if (mShouldDisableView != shouldDisableView) {
mShouldDisableView = shouldDisableView;
notifyChanged();
}
}
/**
* Checks whether this preference should disable its view when it's action is disabled.
*
* @return {@code true} if it should disable the view
* @see #setShouldDisableView(boolean)
*/
public boolean getShouldDisableView() {
return mShouldDisableView;
}
/**
* Sets whether this preference should be visible to the user. If false, it is excluded from
* the adapter, but can still be retrieved using
* {@link PreferenceFragmentCompat#findPreference(CharSequence)}.
*
* <p>To show this preference to the user, its ancestors must also all be visible. If you make
* a {@link PreferenceGroup} invisible, none of its children will be shown to the user until
* the group is visible.
*
* @param visible Set false if this preference should be hidden from the user
* {@link androidx.preference.R.attr#isPreferenceVisible}
* @see #isShown()
*/
public final void setVisible(boolean visible) {
if (mVisible != visible) {
mVisible = visible;
if (mListener != null) {
mListener.onPreferenceVisibilityChange(this);
}
}
}
/**
* Checks whether this preference should be visible to the user.
*
* If this preference is visible, but one or more of its ancestors are not visible, then this
* preference will not be shown until its ancestors are all visible.
*
* @return {@code true} if this preference should be displayed
* @see #setVisible(boolean)
* @see #isShown()
*/
public final boolean isVisible() {
return mVisible;
}
/**
* Checks whether this preference is shown to the user in the hierarchy.
*
* For a preference to be shown in the hierarchy, it and all of its ancestors must be visible
* and attached to the root {@link PreferenceScreen}.
*
* @return {@code true} if this preference is shown to the user in the hierarchy
*/
public final boolean isShown() {
if (!isVisible()) {
return false;
}
if (getPreferenceManager() == null) {
// We are not attached to the hierarchy
return false;
}
if (this == getPreferenceManager().getPreferenceScreen()) {
// We are at the root preference, so this preference and its ancestors are visible
return true;
}
PreferenceGroup parent = getParent();
if (parent == null) {
// We are not attached to the hierarchy
return false;
}
return parent.isShown();
}
/**
* Returns a unique ID for this preference. This ID should be unique across all preference
* objects in a hierarchy.
*
* @return A unique ID for this preference
*/
long getId() {
return mId;
}
/**
* Processes a click on the preference. This includes saving the value to
* the {@link SharedPreferences}. However, the overridden method should
* call {@link #callChangeListener(Object)} to make sure the client wants to
* update the preference's state with the new value.
*/
protected void onClick() {}
/**
* Sets the key for this preference, which is used as a key to the {@link SharedPreferences} or
* {@link PreferenceDataStore}. This should be unique for the package.
*
* @param key The key for the preference
*/
public void setKey(String key) {
mKey = key;
if (mRequiresKey && !hasKey()) {
requireKey();
}
}
/**
* Gets the key for this preference, which is also the key used for storing values into
* {@link SharedPreferences} or {@link PreferenceDataStore}.
*
* @return The key
*/
public String getKey() {
return mKey;
}
/**
* Checks whether the key is present, and if it isn't throws an exception. This should be called
* by subclasses that persist their preferences.
*
* @throws IllegalStateException If there is no key assigned.
*/
void requireKey() {
if (TextUtils.isEmpty(mKey)) {
throw new IllegalStateException("Preference does not have a key assigned.");
}
mRequiresKey = true;
}
/**
* Checks whether this preference has a valid key.
*
* @return {@code true} if the key exists and is not a blank string, false otherwise
*/
public boolean hasKey() {
return !TextUtils.isEmpty(mKey);
}
/**
* Checks whether this preference is persistent. If it is, it stores its value(s) into
* the persistent {@link SharedPreferences} storage by default or into
* {@link PreferenceDataStore} if assigned.
*
* @return {@code true} if persistent
*/
public boolean isPersistent() {
return mPersistent;
}
/**
* Checks whether, at the given time this method is called, this preference should store/restore
* its value(s) into the {@link SharedPreferences} or into {@link PreferenceDataStore} if
* assigned. This, at minimum, checks whether this preference is persistent and it currently has
* a key. Before you save/restore from the storage, check this first.
*
* @return {@code true} if it should persist the value
*/
protected boolean shouldPersist() {
return mPreferenceManager != null && isPersistent() && hasKey();
}
/**
* Sets whether this preference is persistent. When persistent, it stores its value(s) into
* the persistent {@link SharedPreferences} storage by default or into
* {@link PreferenceDataStore} if assigned.
*
* @param persistent Set {@code true} if it should store its value(s) into the storage
*/
public void setPersistent(boolean persistent) {
mPersistent = persistent;
}
/**
* Sets whether to constrain the title of this preference to a single line instead of
* letting it wrap onto multiple lines.
*
* @param singleLineTitle Set {@code true} if the title should be constrained to one line
* {@link android.R.attr#singleLineTitle}
*/
public void setSingleLineTitle(boolean singleLineTitle) {
mHasSingleLineTitleAttr = true;
mSingleLineTitle = singleLineTitle;
}
/**
* Gets whether the title of this preference is constrained to a single line.
*
* @return {@code true} if the title of this preference is constrained to a single line
* {@link android.R.attr#singleLineTitle}
* @see #setSingleLineTitle(boolean)
*/
public boolean isSingleLineTitle() {
return mSingleLineTitle;
}
/**
* Sets whether to reserve the space of this preference icon view when no icon is provided. If
* set to true, the preference will be offset as if it would have the icon and thus aligned with
* other preferences having icons.
*
* @param iconSpaceReserved Set {@code true} if the space for the icon view should be reserved
* {@link android.R.attr#iconSpaceReserved}
*/
public void setIconSpaceReserved(boolean iconSpaceReserved) {
if (mIconSpaceReserved != iconSpaceReserved) {
mIconSpaceReserved = iconSpaceReserved;
notifyChanged();
}
}
/**
* Returns whether the space of this preference icon view is reserved.
*
* @return {@code true} if the space of this preference icon view is reserved
* {@link android.R.attr#iconSpaceReserved}
* @see #setIconSpaceReserved(boolean)
*/
public boolean isIconSpaceReserved() {
return mIconSpaceReserved;
}
/**
* Sets whether the summary of this preference can be copied to the clipboard by
* long pressing on the preference.
*
* @param enabled Set true to enable copying the summary of this preference
*/
public void setCopyingEnabled(boolean enabled) {
if (mCopyingEnabled != enabled) {
mCopyingEnabled = enabled;
notifyChanged();
}
}
/**
* Returns whether the summary of this preference can be copied to the clipboard by
* long pressing on the preference.
*
* @return {@code true} if copying is enabled, false otherwise
*/
public boolean isCopyingEnabled() {
return mCopyingEnabled;
}
/**
* Set a {@link SummaryProvider} that will be invoked whenever the summary of this preference
* is requested. Set {@code null} to remove the existing SummaryProvider.
*
* @param summaryProvider The {@link SummaryProvider} that will be invoked whenever the
* summary of this preference is requested
* @see SummaryProvider
*/
public final void setSummaryProvider(@Nullable SummaryProvider summaryProvider) {
mSummaryProvider = summaryProvider;
notifyChanged();
}
/**
* Returns the {@link SummaryProvider} used to configure the summary of this preference.
*
* @return The {@link SummaryProvider} used to configure the summary of this preference, or
* {@code null} if there is no SummaryProvider set
* @see SummaryProvider
*/
@Nullable
public final SummaryProvider getSummaryProvider() {
return mSummaryProvider;
}
/**
* Call this method after the user changes the preference, but before the internal state is
* set. This allows the client to ignore the user value.
*
* @param newValue The new value of this preference
* @return {@code true} if the user value should be set as the preference value (and persisted)
*/
public boolean callChangeListener(Object newValue) {
return mOnChangeListener == null || mOnChangeListener.onPreferenceChange(this, newValue);
}
/**
* Sets the callback to be invoked when this preference is changed by the user (but before
* the internal state has been updated).
*
* @param onPreferenceChangeListener The callback to be invoked
*/
public void setOnPreferenceChangeListener(
@Nullable OnPreferenceChangeListener onPreferenceChangeListener) {
mOnChangeListener = onPreferenceChangeListener;
}
/**
* Returns the callback to be invoked when this preference is changed by the user (but before
* the internal state has been updated).
*
* @return The callback to be invoked
*/
@Nullable
public OnPreferenceChangeListener getOnPreferenceChangeListener() {
return mOnChangeListener;
}
/**
* Sets the callback to be invoked when this preference is clicked.
*
* @param onPreferenceClickListener The callback to be invoked
*/
public void setOnPreferenceClickListener(
@Nullable OnPreferenceClickListener onPreferenceClickListener) {
mOnClickListener = onPreferenceClickListener;
}
/**
* Returns the callback to be invoked when this preference is clicked.
*
* @return The callback to be invoked
*/
@Nullable
public OnPreferenceClickListener getOnPreferenceClickListener() {
return mOnClickListener;
}
/**
* Used by Settings.
* @hide
*/
@RestrictTo(LIBRARY_GROUP_PREFIX)
protected void performClick(@NonNull View view) {
performClick();
}
/**
* Called when a click should be performed.
*
* Used by Settings.
* @hide
*/
@RestrictTo(LIBRARY_GROUP_PREFIX)
public void performClick() {
if (!isEnabled() || !isSelectable()) {
return;
}
onClick();
if (mOnClickListener != null && mOnClickListener.onPreferenceClick(this)) {
return;
}
PreferenceManager preferenceManager = getPreferenceManager();
if (preferenceManager != null) {
PreferenceManager.OnPreferenceTreeClickListener listener = preferenceManager
.getOnPreferenceTreeClickListener();
if (listener != null && listener.onPreferenceTreeClick(this)) {
return;
}
}
if (mIntent != null) {
Context context = getContext();
context.startActivity(mIntent);
}
}
/**
* Returns the {@link Context} of this preference.
* Each preference in a preference hierarchy can be from different Context (for example, if
* multiple activities provide preferences into a single {@link PreferenceFragmentCompat}).
* This Context will be used to save the preference values.
*
* @return The Context of this preference
*/
@NonNull
public Context getContext() {
return mContext;
}
/**
* Returns the {@link SharedPreferences} where this preference can read its
* value(s). Usually, it's easier to use one of the helper read methods:
* {@link #getPersistedBoolean(boolean)}, {@link #getPersistedFloat(float)},
* {@link #getPersistedInt(int)}, {@link #getPersistedLong(long)},
* {@link #getPersistedString(String)}.
*
* @return The {@link SharedPreferences} where this preference reads its value(s). If this
* preference is not attached to a preference hierarchy or if a
* {@link PreferenceDataStore} has been set, this method returns {@code null}.
* @see #setPreferenceDataStore(PreferenceDataStore)
*/
@Nullable
public SharedPreferences getSharedPreferences() {
if (mPreferenceManager == null || getPreferenceDataStore() != null) {
return null;
}
return mPreferenceManager.getSharedPreferences();
}
/**
* Compares preference objects based on order (if set), otherwise alphabetically on the titles.
*
* @param another The preference to compare to this one
* @return 0 if the same; less than 0 if this preference sorts ahead of <var>another</var>;
* greater than 0 if this preference sorts after <var>another</var>.
*/
@Override
public int compareTo(@NonNull Preference another) {
if (mOrder != another.mOrder) {
// Do order comparison
return mOrder - another.mOrder;
} else if (mTitle == another.mTitle) {
// If titles are null or share same object comparison
return 0;
} else if (mTitle == null) {
return 1;
} else if (another.mTitle == null) {
return -1;
} else {
// Do name comparison
return mTitle.toString().compareToIgnoreCase(another.mTitle.toString());
}
}
/**
* Sets the internal change listener.
*
* @param listener The listener
* @see #notifyChanged()
*/
final void setOnPreferenceChangeInternalListener(
@Nullable OnPreferenceChangeInternalListener listener) {
mListener = listener;
}
/**
* Should be called when the data of this {@link Preference} has changed.
*/
protected void notifyChanged() {
if (mListener != null) {
mListener.onPreferenceChange(this);
}
}
/**
* Should be called when a preference has been added/removed from this group, or the ordering
* should be re-evaluated.
*/
protected void notifyHierarchyChanged() {
if (mListener != null) {
mListener.onPreferenceHierarchyChange(this);
}
}
/**
* Gets the {@link PreferenceManager} that manages this preference object's tree.
*
* @return The {@link PreferenceManager}
*/
public PreferenceManager getPreferenceManager() {
return mPreferenceManager;
}
/**
* Called when this preference has been attached to a preference hierarchy. Make sure to call
* the super implementation.
*
* @param preferenceManager The PreferenceManager of the hierarchy
*/
protected void onAttachedToHierarchy(@NonNull PreferenceManager preferenceManager) {
mPreferenceManager = preferenceManager;
if (!mHasId) {
mId = preferenceManager.getNextId();
}
dispatchSetInitialValue();
}
/**
* Called from {@link PreferenceGroup} to pass in an ID for reuse.
*
* Used by Settings.
*
* @hide
*/
@RestrictTo(LIBRARY_GROUP_PREFIX)
protected void onAttachedToHierarchy(@NonNull PreferenceManager preferenceManager, long id) {
mId = id;
mHasId = true;
try {
onAttachedToHierarchy(preferenceManager);
} finally {
mHasId = false;
}
}
/**
* Assigns a {@link PreferenceGroup} as the parent of this preference. Set {@code null} to
* remove the current parent.
*
* @param parentGroup Parent preference group of this preference or {@code null} if none
*
* @throws IllegalStateException If the preference already has a parent assigned.
*/
void assignParent(@Nullable PreferenceGroup parentGroup) {
if (parentGroup != null && mParentGroup != null) {
throw new IllegalStateException(
"This preference already has a parent. You must remove the existing parent "
+ "before assigning a new one.");
}
mParentGroup = parentGroup;
}
/**
* Called when the preference hierarchy has been attached to the list of preferences. This
* can also be called when this preference has been attached to a group that was already
* attached to the list of preferences.
*/
public void onAttached() {
// At this point, the hierarchy that this preference is in is connected
// with all other preferences.
registerDependency();
}
/**
* Called when the preference hierarchy has been detached from the list of preferences. This
* can also be called when this preference has been removed from a group that was attached to
* the list of preferences.
*/
public void onDetached() {
unregisterDependency();
mWasDetached = true;
}
/**
* Returns true if {@link #onDetached()} was called. Used for handling the case when a
* preference was removed, modified, and re-added to a {@link PreferenceGroup}.
*/
final boolean wasDetached() {
return mWasDetached;
}
/**
* Clears the {@link #wasDetached()} status.
*/
final void clearWasDetached() {
mWasDetached = false;
}
private void registerDependency() {
if (TextUtils.isEmpty(mDependencyKey)) return;
Preference preference = findPreferenceInHierarchy(mDependencyKey);
if (preference != null) {
preference.registerDependent(this);
} else {
throw new IllegalStateException("Dependency \"" + mDependencyKey
+ "\" not found for preference \"" + mKey + "\" (title: \"" + mTitle + "\"");
}
}
private void unregisterDependency() {
if (mDependencyKey != null) {
final Preference oldDependency = findPreferenceInHierarchy(mDependencyKey);
if (oldDependency != null) {
oldDependency.unregisterDependent(this);
}
}
}
/**
* Finds a preference in the entire hierarchy (above or below this preference) with the given
* key. Returns {@code null} if no preference could be found with the given key.
*
* <p>This only works after this preference has been attached to a hierarchy.
*
* @param key The key of the preference to retrieve
* @return The preference with the key, or {@code null}
* @see PreferenceGroup#findPreference(CharSequence)
*/
@SuppressWarnings("TypeParameterUnusedInFormals")
@Nullable
protected <T extends Preference> T findPreferenceInHierarchy(@NonNull String key) {
if (mPreferenceManager == null) {
return null;
}
return mPreferenceManager.findPreference(key);
}
/**
* Adds a dependent preference on this preference so we can notify it. Usually, the dependent
* preference registers itself (it's good for it to know it depends on something), so please
* use {@link Preference#setDependency(String)} on the dependent preference.
*
* @param dependent The dependent preference that will be enabled/disabled
* according to the state of this preference.
*/
private void registerDependent(Preference dependent) {
if (mDependents == null) {
mDependents = new ArrayList<>();
}
mDependents.add(dependent);
dependent.onDependencyChanged(this, shouldDisableDependents());
}
/**
* Removes a dependent preference on this preference.
*
* @param dependent The dependent preference that will be enabled/disabled
* according to the state of this preference.
*/
private void unregisterDependent(Preference dependent) {
if (mDependents != null) {
mDependents.remove(dependent);
}
}
/**
* Notifies any listening dependents of a change that affects the dependency.
*
* @param disableDependents Whether this preference should disable
* its dependents.
*/
public void notifyDependencyChange(boolean disableDependents) {
final List<Preference> dependents = mDependents;
if (dependents == null) {
return;
}
final int dependentsCount = dependents.size();
for (int i = 0; i < dependentsCount; i++) {
dependents.get(i).onDependencyChanged(this, disableDependents);
}
}
/**
* Called when the dependency changes.
*
* @param dependency The preference that this preference depends on
* @param disableDependent Set true to disable this preference
*/
public void onDependencyChanged(@NonNull Preference dependency, boolean disableDependent) {
if (mDependencyMet == disableDependent) {
mDependencyMet = !disableDependent;
// Enabled state can change dependent preferences' states, so notify
notifyDependencyChange(shouldDisableDependents());
notifyChanged();
}
}
/**
* Called when the implicit parent dependency changes.
*
* @param parent The preference that this preference depends on
* @param disableChild Set true to disable this preference
*/
public void onParentChanged(@NonNull Preference parent, boolean disableChild) {
if (mParentDependencyMet == disableChild) {
mParentDependencyMet = !disableChild;
// Enabled state can change dependent preferences' states, so notify
notifyDependencyChange(shouldDisableDependents());
notifyChanged();
}
}
/**
* Checks whether this preference's dependents should currently be disabled.
*
* @return {@code true} if the dependents should be disabled, otherwise false
*/
public boolean shouldDisableDependents() {
return !isEnabled();
}
/**
* Sets the key of a preference that this preference will depend on. If that preference is
* not set or is off, this preference will be disabled.
*
* @param dependencyKey The key of the preference that this depends on
*/
public void setDependency(@Nullable String dependencyKey) {
// Unregister the old dependency, if we had one
unregisterDependency();
// Register the new
mDependencyKey = dependencyKey;
registerDependency();
}
/**
* Returns the key of the dependency on this preference.
*
* @return The key of the dependency
* @see #setDependency(String)
*/
@Nullable
public String getDependency() {
return mDependencyKey;
}
/**
* Returns the {@link PreferenceGroup} which is this preference assigned to or {@code null}
* if this preference is not assigned to any group or is a root preference.
*
* @return The parent PreferenceGroup or {@code null} if not attached to any
*/
@Nullable
public PreferenceGroup getParent() {
return mParentGroup;
}
/**
* Called when this preference is being removed from the hierarchy. You should remove any
* references to this preference that you know about. Make sure to call through to the
* superclass implementation.
*/
protected void onPrepareForRemoval() {
unregisterDependency();
}
/**
* Sets the default value for this preference, which will be set either if persistence is off
* or persistence is on and the preference is not found in the persistent storage.
*
* @param defaultValue The default value
*/
public void setDefaultValue(Object defaultValue) {
mDefaultValue = defaultValue;
}
private void dispatchSetInitialValue() {
if (getPreferenceDataStore() != null) {
onSetInitialValue(true, mDefaultValue);
return;
}
// By now, we know if we are persistent.
final boolean shouldPersist = shouldPersist();
if (!shouldPersist || !getSharedPreferences().contains(mKey)) {
if (mDefaultValue != null) {
onSetInitialValue(false, mDefaultValue);
}
} else {
onSetInitialValue(true, null);
}
}
/**
* Implement this to set the initial value of the preference.
*
* <p>If <var>restorePersistedValue</var> is true, you should restore the preference value
* from the {@link SharedPreferences}. If <var>restorePersistedValue</var> is
* false, you should set the preference value to defaultValue that is given (and possibly
* store to SharedPreferences if {@link #shouldPersist()} is true).
*
* <p>In case of using {@link PreferenceDataStore}, the <var>restorePersistedValue</var> is
* always {@code true} but the default value (if provided) is set.
*
* <p>This may not always be called. One example is if it should not persist but there is no
* default value given.
*
* @param restorePersistedValue True to restore the persisted value;
* false to use the given <var>defaultValue</var>.
* @param defaultValue The default value for this preference. Only use this
* if <var>restorePersistedValue</var> is false.
*
* @deprecated Use {@link #onSetInitialValue(Object)} instead.
*/
@Deprecated
protected void onSetInitialValue(boolean restorePersistedValue, Object defaultValue) {
onSetInitialValue(defaultValue);
}
/**
* Implement this to set the initial value of the preference.
*
* <p>If you are persisting values to {@link SharedPreferences} or a {@link PreferenceDataStore}
* you should restore the saved value for the preference.
*
* <p>If you are not persisting values, or there is no value saved for the preference, you
* should set the value of the preference to <var>defaultValue</var>.
*
* @param defaultValue The default value for the preference if set, otherwise {@code null}.
*/
protected void onSetInitialValue(@Nullable Object defaultValue) {}
private void tryCommit(@NonNull SharedPreferences.Editor editor) {
if (mPreferenceManager.shouldCommit()) {
editor.apply();
}
}
/**
* Attempts to persist a {@link String} if this preference is persistent.
*
* <p>The returned value doesn't reflect whether the given value was persisted, since we may not
* necessarily commit if there will be a batch commit later.
*
* @param value The value to persist
* @return {@code true} if the preference is persistent, {@code false} otherwise
* @see #getPersistedString(String)
*/
protected boolean persistString(String value) {
if (!shouldPersist()) {
return false;
}
// Shouldn't store null
if (TextUtils.equals(value, getPersistedString(null))) {
// It's already there, so the same as persisting
return true;
}
PreferenceDataStore dataStore = getPreferenceDataStore();
if (dataStore != null) {
dataStore.putString(mKey, value);
} else {
SharedPreferences.Editor editor = mPreferenceManager.getEditor();
editor.putString(mKey, value);
tryCommit(editor);
}
return true;
}
/**
* Attempts to get a persisted set of Strings if this preference is persistent.
*
* @param defaultReturnValue The default value to return if either the preference is not
* persistent or the preference is not in the shared preferences.
* @return The value from the storage or the default return value
* @see #persistString(String)
*/
protected String getPersistedString(String defaultReturnValue) {
if (!shouldPersist()) {
return defaultReturnValue;
}
PreferenceDataStore dataStore = getPreferenceDataStore();
if (dataStore != null) {
return dataStore.getString(mKey, defaultReturnValue);
}
return mPreferenceManager.getSharedPreferences().getString(mKey, defaultReturnValue);
}
/**
* Attempts to persist a set of Strings if this preference is persistent.
*
* <p>The returned value doesn't reflect whether the given value was persisted, since we may not
* necessarily commit if there will be a batch commit later.
*
* @param values The values to persist
* @return {@code true} if the preference is persistent, {@code false} otherwise
* @see #getPersistedStringSet(Set)
*/
public boolean persistStringSet(Set<String> values) {
if (!shouldPersist()) {
return false;
}
// Shouldn't store null
if (values.equals(getPersistedStringSet(null))) {
// It's already there, so the same as persisting
return true;
}
PreferenceDataStore dataStore = getPreferenceDataStore();
if (dataStore != null) {
dataStore.putStringSet(mKey, values);
} else {
SharedPreferences.Editor editor = mPreferenceManager.getEditor();
editor.putStringSet(mKey, values);
tryCommit(editor);
}
return true;
}
/**
* Attempts to get a persisted set of Strings if this preference is persistent.
*
* @param defaultReturnValue The default value to return if either this preference is not
* persistent or this preference is not present.
* @return The value from the storage or the default return value
* @see #persistStringSet(Set)
*/
public Set<String> getPersistedStringSet(Set<String> defaultReturnValue) {
if (!shouldPersist()) {
return defaultReturnValue;
}
PreferenceDataStore dataStore = getPreferenceDataStore();
if (dataStore != null) {
return dataStore.getStringSet(mKey, defaultReturnValue);
}
return mPreferenceManager.getSharedPreferences().getStringSet(mKey, defaultReturnValue);
}
/**
* Attempts to persist an {@link Integer} if this preference is persistent.
*
* <p>The returned value doesn't reflect whether the given value was persisted, since we may not
* necessarily commit if there will be a batch commit later.
*
* @param value The value to persist
* @return {@code true} if the preference is persistent, {@code false} otherwise
* @see #persistString(String)
* @see #getPersistedInt(int)
*/
protected boolean persistInt(int value) {
if (!shouldPersist()) {
return false;
}
if (value == getPersistedInt(~value)) {
// It's already there, so the same as persisting
return true;
}
PreferenceDataStore dataStore = getPreferenceDataStore();
if (dataStore != null) {
dataStore.putInt(mKey, value);
} else {
SharedPreferences.Editor editor = mPreferenceManager.getEditor();
editor.putInt(mKey, value);
tryCommit(editor);
}
return true;
}
/**
* Attempts to get a persisted {@link Integer} if this preference is persistent.
*
* @param defaultReturnValue The default value to return if either this preference is not
* persistent or this preference is not in the SharedPreferences.
* @return The value from the storage or the default return value
* @see #getPersistedString(String)
* @see #persistInt(int)
*/
protected int getPersistedInt(int defaultReturnValue) {
if (!shouldPersist()) {
return defaultReturnValue;
}
PreferenceDataStore dataStore = getPreferenceDataStore();
if (dataStore != null) {
return dataStore.getInt(mKey, defaultReturnValue);
}
return mPreferenceManager.getSharedPreferences().getInt(mKey, defaultReturnValue);
}
/**
* Attempts to persist a {@link Float} if this preference is persistent.
*
* <p>The returned value doesn't reflect whether the given value was persisted, since we may not
* necessarily commit if there will be a batch commit later.
*
* @param value The value to persist
* @return {@code true} if the preference is persistent, {@code false} otherwise
* @see #persistString(String)
* @see #getPersistedFloat(float)
*/
protected boolean persistFloat(float value) {
if (!shouldPersist()) {
return false;
}
if (value == getPersistedFloat(Float.NaN)) {
// It's already there, so the same as persisting
return true;
}
PreferenceDataStore dataStore = getPreferenceDataStore();
if (dataStore != null) {
dataStore.putFloat(mKey, value);
} else {
SharedPreferences.Editor editor = mPreferenceManager.getEditor();
editor.putFloat(mKey, value);
tryCommit(editor);
}
return true;
}
/**
* Attempts to get a persisted {@link Float} if this preference is persistent.
*
* @param defaultReturnValue The default value to return if either this preference is not
* persistent or this preference is not saved.
* @return The value from the storage or the default return value
* @see #getPersistedString(String)
* @see #persistFloat(float)
*/
protected float getPersistedFloat(float defaultReturnValue) {
if (!shouldPersist()) {
return defaultReturnValue;
}
PreferenceDataStore dataStore = getPreferenceDataStore();
if (dataStore != null) {
return dataStore.getFloat(mKey, defaultReturnValue);
}
return mPreferenceManager.getSharedPreferences().getFloat(mKey, defaultReturnValue);
}
/**
* Attempts to persist a {@link Long} if this preference is persistent.
*
* <p>The returned value doesn't reflect whether the given value was persisted, since we may not
* necessarily commit if there will be a batch commit later.
*
* @param value The value to persist
* @return {@code true} if the preference is persistent, {@code false} otherwise
* @see #persistString(String)
* @see #getPersistedLong(long)
*/
protected boolean persistLong(long value) {
if (!shouldPersist()) {
return false;
}
if (value == getPersistedLong(~value)) {
// It's already there, so the same as persisting
return true;
}
PreferenceDataStore dataStore = getPreferenceDataStore();
if (dataStore != null) {
dataStore.putLong(mKey, value);
} else {
SharedPreferences.Editor editor = mPreferenceManager.getEditor();
editor.putLong(mKey, value);
tryCommit(editor);
}
return true;
}
/**
* Attempts to get a persisted {@link Long} if this preference is persistent.
*
* @param defaultReturnValue The default value to return if either this preference is not
* persistent or this preference is not in the SharedPreferences.
* @return The value from the storage or the default return value
* @see #getPersistedString(String)
* @see #persistLong(long)
*/
protected long getPersistedLong(long defaultReturnValue) {
if (!shouldPersist()) {
return defaultReturnValue;
}
PreferenceDataStore dataStore = getPreferenceDataStore();
if (dataStore != null) {
return dataStore.getLong(mKey, defaultReturnValue);
}
return mPreferenceManager.getSharedPreferences().getLong(mKey, defaultReturnValue);
}
/**
* Attempts to persist a {@link Boolean} if this preference is persistent.
*
* <p>The returned value doesn't reflect whether the given value was persisted, since we may not
* necessarily commit if there will be a batch commit later.
*
* @param value The value to persist
* @return {@code true} if the preference is persistent, {@code false} otherwise
* @see #persistString(String)
* @see #getPersistedBoolean(boolean)
*/
protected boolean persistBoolean(boolean value) {
if (!shouldPersist()) {
return false;
}
if (value == getPersistedBoolean(!value)) {
// It's already there, so the same as persisting
return true;
}
PreferenceDataStore dataStore = getPreferenceDataStore();
if (dataStore != null) {
dataStore.putBoolean(mKey, value);
} else {
SharedPreferences.Editor editor = mPreferenceManager.getEditor();
editor.putBoolean(mKey, value);
tryCommit(editor);
}
return true;
}
/**
* Attempts to get a persisted {@link Boolean} if this preference is persistent.
*
* @param defaultReturnValue The default value to return if either this preference is not
* persistent or this preference is not in the SharedPreferences.
* @return The value from the storage or the default return value
* @see #getPersistedString(String)
* @see #persistBoolean(boolean)
*/
protected boolean getPersistedBoolean(boolean defaultReturnValue) {
if (!shouldPersist()) {
return defaultReturnValue;
}
PreferenceDataStore dataStore = getPreferenceDataStore();
if (dataStore != null) {
return dataStore.getBoolean(mKey, defaultReturnValue);
}
return mPreferenceManager.getSharedPreferences().getBoolean(mKey, defaultReturnValue);
}
@NonNull
@Override
public String toString() {
return getFilterableStringBuilder().toString();
}
/**
* Returns the text that will be used to filter this preference depending on user input.
*
* <p>If overriding and calling through to the superclass, make sure to prepend your
* additions with a space.
*
* @return Text as a {@link StringBuilder} that will be used to filter this preference. By
* default, this is the title and summary (concatenated with a space).
*/
@NonNull
StringBuilder getFilterableStringBuilder() {
StringBuilder sb = new StringBuilder();
CharSequence title = getTitle();
if (!TextUtils.isEmpty(title)) {
sb.append(title).append(' ');
}
CharSequence summary = getSummary();
if (!TextUtils.isEmpty(summary)) {
sb.append(summary).append(' ');
}
if (sb.length() > 0) {
// Drop the last space
sb.setLength(sb.length() - 1);
}
return sb;
}
/**
* Store this preference hierarchy's frozen state into the given container.
*
* @param container The Bundle in which to save the instance of this preference
* @see #restoreHierarchyState
* @see #onSaveInstanceState
*/
public void saveHierarchyState(@NonNull Bundle container) {
dispatchSaveInstanceState(container);
}
/**
* Called by {@link #saveHierarchyState} to store the instance for this preference and its
* children. May be overridden to modify how the save happens for children. For example, some
* preference objects may want to not store an instance for their children.
*
* @param container The Bundle in which to save the instance of this preference
* @see #saveHierarchyState
* @see #onSaveInstanceState
*/
void dispatchSaveInstanceState(@NonNull Bundle container) {
if (hasKey()) {
mBaseMethodCalled = false;
Parcelable state = onSaveInstanceState();
if (!mBaseMethodCalled) {
throw new IllegalStateException(
"Derived class did not call super.onSaveInstanceState()");
}
if (state != null) {
container.putParcelable(mKey, state);
}
}
}
/**
* Hook allowing a preference to generate a representation of its internal state that can
* later be used to create a new instance with that same state. This state should only
* contain information that is not persistent or can be reconstructed later.
*
* @return A Parcelable object containing the current dynamic state of this preference, or
* {@code null} if there is nothing interesting to save. The default implementation returns
* {@code null}.
* @see #onRestoreInstanceState
* @see #saveHierarchyState
*/
@Nullable
protected Parcelable onSaveInstanceState() {
mBaseMethodCalled = true;
return BaseSavedState.EMPTY_STATE;
}
/**
* Restore this preference hierarchy's previously saved state from the given container.
*
* @param container The Bundle that holds the previously saved state
* @see #saveHierarchyState
* @see #onRestoreInstanceState
*/
public void restoreHierarchyState(@NonNull Bundle container) {
dispatchRestoreInstanceState(container);
}
/**
* Called by {@link #restoreHierarchyState} to retrieve the saved state for this preference
* and its children. May be overridden to modify how restoring happens to the children of a
* preference. For example, some preference objects may not want to save state for their
* children.
*
* @param container The Bundle that holds the previously saved state
* @see #restoreHierarchyState
* @see #onRestoreInstanceState
*/
void dispatchRestoreInstanceState(@NonNull Bundle container) {
if (hasKey()) {
Parcelable state = container.getParcelable(mKey);
if (state != null) {
mBaseMethodCalled = false;
onRestoreInstanceState(state);
if (!mBaseMethodCalled) {
throw new IllegalStateException(
"Derived class did not call super.onRestoreInstanceState()");
}
}
}
}
/**
* Hook allowing a preference to re-apply a representation of its internal state that had
* previously been generated by {@link #onSaveInstanceState}. This function will never be
* called with a null state.
*
* @param state The saved state that had previously been returned by
* {@link #onSaveInstanceState}.
* @see #onSaveInstanceState
* @see #restoreHierarchyState
*/
protected void onRestoreInstanceState(@Nullable Parcelable state) {
mBaseMethodCalled = true;
if (state != BaseSavedState.EMPTY_STATE && state != null) {
throw new IllegalArgumentException("Wrong state class -- expecting Preference State");
}
}
/**
* Initializes an {@link android.view.accessibility.AccessibilityNodeInfo} with information
* about the View for this preference.
*
* @deprecated Preferences aren't views. They should not need any accessibility changes,
* unless the view hierarchy is customized. In this situation, please add Accessibility
* information in {@link #onBindViewHolder}.
*/
@CallSuper
@Deprecated
public void onInitializeAccessibilityNodeInfo(AccessibilityNodeInfoCompat info) {}
/**
* Interface definition for a callback to be invoked when the value of this
* {@link Preference} has been changed by the user and is about to be set and/or persisted.
* This gives the client a chance to prevent setting and/or persisting the value.
*/
public interface OnPreferenceChangeListener {
/**
* Called when a preference has been changed by the user. This is called before the state
* of the preference is about to be updated and before the state is persisted.
*
* @param preference The changed preference
* @param newValue The new value of the preference
* @return {@code true} to update the state of the preference with the new value
*/
boolean onPreferenceChange(@NonNull Preference preference, Object newValue);
}
/**
* Interface definition for a callback to be invoked when a {@link Preference} is clicked.
*/
public interface OnPreferenceClickListener {
/**
* Called when a preference has been clicked.
*
* @param preference The preference that was clicked
* @return {@code true} if the click was handled
*/
boolean onPreferenceClick(@NonNull Preference preference);
}
/**
* Interface definition for a callback to be invoked when this {@link Preference} is changed
* or, if this is a group, there is an addition/removal of {@link Preference}(s). This is
* used internally.
*/
interface OnPreferenceChangeInternalListener {
/**
* Called when this preference has changed.
*
* @param preference This preference
*/
void onPreferenceChange(@NonNull Preference preference);
/**
* Called when this group has added/removed {@link Preference}(s).
*
* @param preference This preference
*/
void onPreferenceHierarchyChange(@NonNull Preference preference);
/**
* Called when this preference has changed its visibility.
*
* @param preference This preference
*/
void onPreferenceVisibilityChange(@NonNull Preference preference);
}
/**
* Interface definition for a callback to be invoked when the summary of this
* {@link Preference} is requested (typically when this preference is added to the hierarchy
* or its value is updated). Implement this to allow dynamically configuring a summary.
*
* <p> If a SummaryProvider is set, {@link #setSummary(CharSequence)} will throw an
* exception, and any existing value for the summary will not be used. The value returned by
* the SummaryProvider will be used instead whenever {@link #getSummary()} is called on this
* preference.
*
* <p> Simple implementations are provided for {@link EditTextPreference} and
* {@link ListPreference}. To enable these implementations, use
* {@link #setSummaryProvider(SummaryProvider)} with
* {@link EditTextPreference.SimpleSummaryProvider#getInstance()} or
* {@link ListPreference.SimpleSummaryProvider#getInstance()}.
*
* @param <T> The Preference class that a summary is being requested for
*/
public interface SummaryProvider<T extends Preference> {
/**
* Called whenever {@link #getSummary()} is called on this preference.
*
* @param preference This preference
* @return A CharSequence that will be displayed as the summary for this preference
*/
@Nullable
CharSequence provideSummary(@NonNull T preference);
}
/**
* A base class for managing the instance state of a {@link Preference}.
*/
public static class BaseSavedState extends AbsSavedState {
@NonNull
public static final Parcelable.Creator<BaseSavedState> CREATOR =
new Parcelable.Creator<BaseSavedState>() {
@Override
public BaseSavedState createFromParcel(Parcel in) {
return new BaseSavedState(in);
}
@Override
public BaseSavedState[] newArray(int size) {
return new BaseSavedState[size];
}
};
public BaseSavedState(Parcel source) {
super(source);
}
public BaseSavedState(Parcelable superState) {
super(superState);
}
}
/**
* Handles creating a context menu to allow copying a {@link Preference} and copying the
* summary of the preference to the clipboard.
*
* @see #setCopyingEnabled(boolean)
*/
private static class OnPreferenceCopyListener implements View.OnCreateContextMenuListener,
MenuItem.OnMenuItemClickListener {
private final Preference mPreference;
OnPreferenceCopyListener(@NonNull Preference preference) {
mPreference = preference;
}
@Override
public void onCreateContextMenu(ContextMenu menu, View v,
ContextMenu.ContextMenuInfo menuInfo) {
CharSequence summary = mPreference.getSummary();
if (!mPreference.isCopyingEnabled() || TextUtils.isEmpty(summary)) {
return;
}
menu.setHeaderTitle(summary);
menu.add(Menu.NONE, Menu.NONE, Menu.NONE, R.string.copy)
.setOnMenuItemClickListener(this);
}
@Override
public boolean onMenuItemClick(MenuItem item) {
ClipboardManager clipboard =
(ClipboardManager) mPreference.getContext().getSystemService(
Context.CLIPBOARD_SERVICE);
CharSequence summary = mPreference.getSummary();
ClipData clip = ClipData.newPlainText(CLIPBOARD_ID, summary);
clipboard.setPrimaryClip(clip);
Toast.makeText(mPreference.getContext(),
mPreference.getContext().getString(R.string.preference_copied,
summary),
Toast.LENGTH_SHORT).show();
return true;
}
}
}