java.lang.Object
↳androidx.core.view.ActionProvider
Subclasses:
MediaRouteActionProvider, ShareActionProvider
Gradle dependencies
compile group: 'androidx.core', name: 'core', version: '1.9.0-alpha04'
- groupId: androidx.core
- artifactId: core
- version: 1.9.0-alpha04
Artifact androidx.core:core:1.9.0-alpha04 it located at Google repository (https://maven.google.com/)
Androidx artifact mapping:
androidx.core:core com.android.support:support-compat
Androidx class mapping:
androidx.core.view.ActionProvider android.support.v4.view.ActionProvider
Overview
This class is a mediator for accomplishing a given task, for example sharing a file. It is
responsible for creating a view that performs an action that accomplishes the task. This class
also implements other functions such a performing a default action.
An ActionProvider can be
optionally specified for a android.view.MenuItem
and in such a case it will be
responsible for
creating the action view that appears in the as a substitute for
the menu item when the item is displayed as an action item. Also the provider is responsible for
performing a default action if a menu item placed on the overflow menu of the ActionBar is
selected and none of the menu item callbacks has handled the selection. For this case the
provider can also optionally provide a sub-menu for accomplishing the task at hand.
There are two ways for using an action provider for creating and handling of action views:
### Creating a custom action provider
To create a custom action provider, extend ActionProvider and implement
its callback methods as necessary. In particular, implement the following
methods:
- ActionProvider() constructor
- This constructor is passed the application context. You should
save the context in a member field to use in the other callback methods.
- onCreateActionView(MenuItem)
- The system calls this method when the action provider is created.
You define the action provider's layout through the implementation of this
method. Use the context acquired
from the constructor to instantiate a and
inflate your action provider's layout from an XML resource, then hook up
event listeners for the view's components. For example:
public View onCreateActionView(MenuItem forItem) {
// Inflate the action provider to be shown on the action bar.
LayoutInflater layoutInflater = LayoutInflater.from(mContext);
View providerView =
layoutInflater.inflate(R.layout.my_action_provider, null);
ImageButton button =
(ImageButton) providerView.findViewById(R.id.button);
button.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
// Do something...
}
});
return providerView;
}
- onPerformDefaultAction()
The system calls this method when the user selects a menu item from the action
overflow. The action provider should perform a default action for the
menu item. The system does not call this method if the menu item opens a submenu.
If your action provider presents a submenu through the
onPrepareSubMenu() callback, the submenu
appears even if the action provider is in the overflow menu.
Thus, the system never calls onPerformDefaultAction() if there is a submenu.
Note: An activity or a fragment that
implements onOptionsItemSelected()
can override the action
provider's default behavior (unless it uses a submenu) by handling the
item-selected event and returning true
. In this case, the
system does not call
onPerformDefaultAction().
Summary
Constructors |
---|
public | ActionProvider(Context context)
Creates a new instance. |
Methods |
---|
public Context | getContext()
Gets the context associated with this action provider. |
public boolean | hasSubMenu()
Determines if this ActionProvider has a submenu associated with it. |
public boolean | isVisible()
If ActionProvider.overridesItemVisibility() returns true, the return value of this method
will help determine the visibility of the MenuItem this ActionProvider is bound to. |
public abstract View | onCreateActionView()
Factory method for creating new action views. |
public View | onCreateActionView(MenuItem forItem)
Factory method called by the Android framework to create new action views. |
public boolean | onPerformDefaultAction()
Performs an optional default action. |
public void | onPrepareSubMenu(SubMenu subMenu)
Called to prepare an associated submenu for the menu item backed by this ActionProvider. |
public boolean | overridesItemVisibility()
The result of this method determines whether or not ActionProvider.isVisible() will be used
by the MenuItem this ActionProvider is bound to help determine its visibility. |
public void | refreshVisibility()
If this ActionProvider is associated with an item in a menu,
refresh the visibility of the item based on ActionProvider.overridesItemVisibility() and
ActionProvider.isVisible(). |
public void | reset()
|
public void | setSubUiVisibilityListener(ActionProvider.SubUiVisibilityListener listener)
|
public void | setVisibilityListener(ActionProvider.VisibilityListener listener)
Set a listener to be notified when this ActionProvider's overridden visibility changes. |
public void | subUiVisibilityChanged(boolean isVisible)
Notify the system that the visibility of an action view's sub-UI such as an anchored popup
has changed. |
from java.lang.Object | clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
Constructors
public
ActionProvider(Context context)
Creates a new instance.
Parameters:
context: Context for accessing resources.
Methods
public Context
getContext()
Gets the context associated with this action provider.
public abstract View
onCreateActionView()
Factory method for creating new action views.
Returns:
A new action view.
public View
onCreateActionView(MenuItem forItem)
Factory method called by the Android framework to create new action views.
This method returns a new action view for the given MenuItem.
If your ActionProvider implementation overrides the deprecated no-argument overload
ActionProvider.onCreateActionView(), overriding this method for devices running API 16 or later
is recommended but optional. The default implementation calls ActionProvider.onCreateActionView()
for compatibility with applications written for older platform versions.
Parameters:
forItem: MenuItem to create the action view for
Returns:
the new action view
public boolean
overridesItemVisibility()
The result of this method determines whether or not ActionProvider.isVisible() will be used
by the MenuItem
this ActionProvider is bound to help determine its visibility.
Returns:
true if this ActionProvider overrides the visibility of the MenuItem
it is bound to, false otherwise. The default implementation returns false.
See also: ActionProvider.isVisible()
public boolean
isVisible()
If ActionProvider.overridesItemVisibility() returns true, the return value of this method
will help determine the visibility of the MenuItem
this ActionProvider is bound to.
If the MenuItem's visibility is explicitly set to false by the application,
the MenuItem will not be shown, even if this method returns true.
Returns:
true if the MenuItem this ActionProvider is bound to is visible, false if
it is invisible. The default implementation returns true.
public void
refreshVisibility()
If this ActionProvider is associated with an item in a menu,
refresh the visibility of the item based on ActionProvider.overridesItemVisibility() and
ActionProvider.isVisible(). If ActionProvider.overridesItemVisibility() returns false, this call
will have no effect.
public boolean
onPerformDefaultAction()
Performs an optional default action.
For the case of an action provider placed in a menu
item not shown as an action this method is invoked if previous callbacks for processing menu
selection has handled the event.
A menu item selection is processed in the following order:
- Receiving a call to
.
- Receiving a call to
FragmentActivity.onOptionsItemSelected(MenuItem)}
- Receiving a call to
Fragment
Fragment.onOptionsItemSelected(MenuItem)}
- Launching the set via
MenuItem.setIntent(android.content.Intent)
- Invoking this method.
The default implementation does not perform any action and returns false.
public boolean
hasSubMenu()
Determines if this ActionProvider has a submenu associated with it.
Associated submenus will be shown when an action view is not. This provider instance will
receive a call to ActionProvider.onPrepareSubMenu(SubMenu) after the call to ActionProvider.onPerformDefaultAction() and before a submenu is displayed to the user.
Returns:
true if the item backed by this provider should have an associated submenu
public void
onPrepareSubMenu(SubMenu subMenu)
Called to prepare an associated submenu for the menu item backed by this ActionProvider.
if ActionProvider.hasSubMenu() returns true, this method will be called when the menu item is
selected to prepare the submenu for presentation to the user. Apps may use this to create or
alter submenu content right before display.
Parameters:
subMenu: Submenu that will be displayed
public void
subUiVisibilityChanged(boolean isVisible)
Notify the system that the visibility of an action view's sub-UI such as an anchored popup
has changed. This will affect how other system visibility notifications occur.
Set a listener to be notified when this ActionProvider's overridden visibility changes.
This should only be used by MenuItem implementations.
Parameters:
listener: listener to set
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.core.view;
import static androidx.annotation.RestrictTo.Scope.LIBRARY_GROUP_PREFIX;
import android.content.Context;
import android.util.Log;
import android.view.MenuItem;
import android.view.SubMenu;
import android.view.View;
import androidx.annotation.NonNull;
import androidx.annotation.Nullable;
import androidx.annotation.RestrictTo;
/**
* This class is a mediator for accomplishing a given task, for example sharing a file. It is
* responsible for creating a view that performs an action that accomplishes the task. This class
* also implements other functions such a performing a default action.
*
* <p>An ActionProvider can be
* optionally specified for a {@link android.view.MenuItem} and in such a case it will be
* responsible for
* creating the action view that appears in the {@link android.app.ActionBar} as a substitute for
* the menu item when the item is displayed as an action item. Also the provider is responsible for
* performing a default action if a menu item placed on the overflow menu of the ActionBar is
* selected and none of the menu item callbacks has handled the selection. For this case the
* provider can also optionally provide a sub-menu for accomplishing the task at hand.
*
* <p>There are two ways for using an action provider for creating and handling of action views:
*
* <ul><li> Setting the action provider on a {@link android.view.MenuItem} directly by
* calling {@link
* androidx.core.view.MenuItemCompat#setActionProvider(android.view.MenuItem, ActionProvider)}.
* </li>
*
* <li>Declaring the action provider in the menu XML resource. For example:
*
* <pre><code>
* <item android:id="@+id/my_menu_item"
* android:title="@string/my_menu_item_title"
* android:icon="@drawable/my_menu_item_icon"
* android:showAsAction="ifRoom"
* android:actionProviderClass="foo.bar.SomeActionProvider" />
* </code></pre>
* </li></ul></p>
*
* ### Creating a custom action provider
*
* <p>To create a custom action provider, extend ActionProvider and implement
* its callback methods as necessary. In particular, implement the following
* methods:</p>
*
* <dl>
* <dt>{@link #ActionProvider ActionProvider()} constructor</dt>
* <dd>This constructor is passed the application context. You should
* save the context in a member field to use in the other callback methods.</dd>
*
* <dt>{@link #onCreateActionView onCreateActionView(MenuItem)}</dt>
* <dd>The system calls this method when the action provider is created.
* You define the action provider's layout through the implementation of this
* method. Use the context acquired
* from the constructor to instantiate a {@link android.view.LayoutInflater} and
* inflate your action provider's layout from an XML resource, then hook up
* event listeners for the view's components. For example:
*
*<pre>
* public View onCreateActionView(MenuItem forItem) {
* // Inflate the action provider to be shown on the action bar.
* LayoutInflater layoutInflater = LayoutInflater.from(mContext);
* View providerView =
* layoutInflater.inflate(R.layout.my_action_provider, null);
* ImageButton button =
* (ImageButton) providerView.findViewById(R.id.button);
* button.setOnClickListener(new View.OnClickListener() {
* @Override
* public void onClick(View v) {
* // Do something...
* }
* });
* return providerView;
* }</pre>
* </dd>
*
* <dt>{@link #onPerformDefaultAction onPerformDefaultAction()}</dt>
* <dd><p>The system calls this method when the user selects a menu item from the action
* overflow. The action provider should perform a default action for the
* menu item. The system does not call this method if the menu item opens a submenu.</p>
*
* <p>If your action provider presents a submenu through the
* {@link #onPrepareSubMenu onPrepareSubMenu()} callback, the submenu
* appears even if the action provider is in the overflow menu.
* Thus, the system never calls {@link #onPerformDefaultAction
* onPerformDefaultAction()} if there is a submenu.</p>
*
* <p class="note"> <strong>Note:</strong> An activity or a fragment that
* implements <code>onOptionsItemSelected()</code> can override the action
* provider's default behavior (unless it uses a submenu) by handling the
* item-selected event and returning <code>true</code>. In this case, the
* system does not call
* {@link #onPerformDefaultAction onPerformDefaultAction()}.</p></dd>
* </dl>
*
*
* @see androidx.core.view.MenuItemCompat#setActionProvider(android.view.MenuItem, ActionProvider)
* @see androidx.core.view.MenuItemCompat#getActionProvider(android.view.MenuItem)
*/
public abstract class ActionProvider {
private static final String TAG = "ActionProvider(support)";
private final Context mContext;
private SubUiVisibilityListener mSubUiVisibilityListener;
private VisibilityListener mVisibilityListener;
/**
* Creates a new instance.
*
* @param context Context for accessing resources.
*/
public ActionProvider(@NonNull Context context) {
mContext = context;
}
/**
* Gets the context associated with this action provider.
*/
@NonNull
public Context getContext() {
return mContext;
}
/**
* Factory method for creating new action views.
*
* @return A new action view.
*/
@NonNull
public abstract View onCreateActionView();
/**
* Factory method called by the Android framework to create new action views.
* This method returns a new action view for the given MenuItem.
*
* <p>If your ActionProvider implementation overrides the deprecated no-argument overload
* {@link #onCreateActionView()}, overriding this method for devices running API 16 or later
* is recommended but optional. The default implementation calls {@link #onCreateActionView()}
* for compatibility with applications written for older platform versions.</p>
*
* @param forItem MenuItem to create the action view for
* @return the new action view
*/
@SuppressWarnings("unused")
@NonNull
public View onCreateActionView(@NonNull MenuItem forItem) {
return onCreateActionView();
}
/**
* The result of this method determines whether or not {@link #isVisible()} will be used
* by the {@link MenuItem} this ActionProvider is bound to help determine its visibility.
*
* @return true if this ActionProvider overrides the visibility of the MenuItem
* it is bound to, false otherwise. The default implementation returns false.
* @see #isVisible()
*/
public boolean overridesItemVisibility() {
return false;
}
/**
* If {@link #overridesItemVisibility()} returns true, the return value of this method
* will help determine the visibility of the {@link MenuItem} this ActionProvider is bound to.
*
* <p>If the MenuItem's visibility is explicitly set to false by the application,
* the MenuItem will not be shown, even if this method returns true.</p>
*
* @return true if the MenuItem this ActionProvider is bound to is visible, false if
* it is invisible. The default implementation returns true.
*/
public boolean isVisible() {
return true;
}
/**
* If this ActionProvider is associated with an item in a menu,
* refresh the visibility of the item based on {@link #overridesItemVisibility()} and
* {@link #isVisible()}. If {@link #overridesItemVisibility()} returns false, this call
* will have no effect.
*/
public void refreshVisibility() {
if (mVisibilityListener != null && overridesItemVisibility()) {
mVisibilityListener.onActionProviderVisibilityChanged(isVisible());
}
}
/**
* Performs an optional default action.
*
* <p>For the case of an action provider placed in a menu
* item not shown as an action this method is invoked if previous callbacks for processing menu
* selection has handled the event.
*
* <p> A menu item selection is processed in the following order:
*
* <ul><li>Receiving a call to
* {@link android.view.MenuItem.OnMenuItemClickListener#onMenuItemClick
* MenuItem.OnMenuItemClickListener.onMenuItemClick}.</li>
*
* <li>Receiving a call to
* {@link android.app.Activity#onOptionsItemSelected(android.view.MenuItem)}
* FragmentActivity.onOptionsItemSelected(MenuItem)}
* </li>
*
* <li>Receiving a call to
* {@link androidx.fragment.app.Fragment#onOptionsItemSelected(android.view.MenuItem)}
* Fragment.onOptionsItemSelected(MenuItem)}</li>
*
* <li>Launching the {@link android.content.Intent} set via
* {@link android.view.MenuItem#setIntent(android.content.Intent)
* MenuItem.setIntent(android.content.Intent)}
* </li>
*
* <li>Invoking this method.</li></ul>
*
* <p>The default implementation does not perform any action and returns false.
*/
public boolean onPerformDefaultAction() {
return false;
}
/**
* Determines if this ActionProvider has a submenu associated with it.
*
* <p>Associated submenus will be shown when an action view is not. This provider instance will
* receive a call to {@link #onPrepareSubMenu(SubMenu)} after the call to {@link
* #onPerformDefaultAction()} and before a submenu is displayed to the user.
*
* @return true if the item backed by this provider should have an associated submenu
*/
public boolean hasSubMenu() {
return false;
}
/**
* Called to prepare an associated submenu for the menu item backed by this ActionProvider.
*
* <p>if {@link #hasSubMenu()} returns true, this method will be called when the menu item is
* selected to prepare the submenu for presentation to the user. Apps may use this to create or
* alter submenu content right before display.
*
* @param subMenu Submenu that will be displayed
*/
@SuppressWarnings("unused")
public void onPrepareSubMenu(@NonNull SubMenu subMenu) {
}
/**
* Notify the system that the visibility of an action view's sub-UI such as an anchored popup
* has changed. This will affect how other system visibility notifications occur.
*
* @hide Pending future API approval
*/
@RestrictTo(LIBRARY_GROUP_PREFIX)
public void subUiVisibilityChanged(boolean isVisible) {
if (mSubUiVisibilityListener != null) {
mSubUiVisibilityListener.onSubUiVisibilityChanged(isVisible);
}
}
/**
* @hide Internal use only
*/
@RestrictTo(LIBRARY_GROUP_PREFIX)
public void setSubUiVisibilityListener(@Nullable SubUiVisibilityListener listener) {
mSubUiVisibilityListener = listener;
}
/**
* Set a listener to be notified when this ActionProvider's overridden visibility changes.
* This should only be used by MenuItem implementations.
*
* @param listener listener to set
*/
public void setVisibilityListener(@Nullable VisibilityListener listener) {
if (mVisibilityListener != null && listener != null) {
Log.w(TAG, "setVisibilityListener: Setting a new ActionProvider.VisibilityListener " +
"when one is already set. Are you reusing this " + getClass().getSimpleName() +
" instance while it is still in use somewhere else?");
}
mVisibilityListener = listener;
}
/**
* @hide
*/
@RestrictTo(LIBRARY_GROUP_PREFIX)
public void reset() {
mVisibilityListener = null;
mSubUiVisibilityListener = null;
}
/**
* @hide Internal use only
*/
@RestrictTo(LIBRARY_GROUP_PREFIX)
public interface SubUiVisibilityListener {
void onSubUiVisibilityChanged(boolean isVisible);
}
/**
* Listens to changes in visibility as reported by {@link ActionProvider#refreshVisibility()}.
*
* @see ActionProvider#overridesItemVisibility()
* @see ActionProvider#isVisible()
*/
public interface VisibilityListener {
void onActionProviderVisibilityChanged(boolean isVisible);
}
}