public class

TransitionInflater

extends java.lang.Object

 java.lang.Object

↳androidx.transition.TransitionInflater

Gradle dependencies

compile group: 'androidx.transition', name: 'transition', version: '1.4.1'

  • groupId: androidx.transition
  • artifactId: transition
  • version: 1.4.1

Artifact androidx.transition:transition:1.4.1 it located at Google repository (https://maven.google.com/)

Androidx artifact mapping:

androidx.transition:transition com.android.support:transition

Androidx class mapping:

androidx.transition.TransitionInflater android.support.transition.TransitionInflater

Overview

This class inflates scenes and transitions from resource files.

Summary

Methods
public static TransitionInflaterfrom(Context context)

Obtains the TransitionInflater from the given context.

public TransitioninflateTransition(int resource)

Loads a Transition object from a resource

public TransitionManagerinflateTransitionManager(int resource, ViewGroup sceneRoot)

Loads a TransitionManager object from a resource

from java.lang.Objectclone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods

public static TransitionInflater from(Context context)

Obtains the TransitionInflater from the given context.

public Transition inflateTransition(int resource)

Loads a Transition object from a resource

Parameters:

resource: The resource id of the transition to load

Returns:

The loaded Transition object

public TransitionManager inflateTransitionManager(int resource, ViewGroup sceneRoot)

Loads a TransitionManager object from a resource

Parameters:

resource: The resource id of the transition manager to load

Returns:

The loaded TransitionManager object

Source

/*
 * Copyright (C) 2017 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.transition;

import android.annotation.SuppressLint;
import android.content.Context;
import android.content.res.Resources;
import android.content.res.TypedArray;
import android.content.res.XmlResourceParser;
import android.util.AttributeSet;
import android.util.Xml;
import android.view.InflateException;
import android.view.ViewGroup;

import androidx.annotation.NonNull;
import androidx.collection.ArrayMap;
import androidx.core.content.res.TypedArrayUtils;

import org.xmlpull.v1.XmlPullParser;
import org.xmlpull.v1.XmlPullParserException;

import java.io.IOException;
import java.lang.reflect.Constructor;

/**
 * This class inflates scenes and transitions from resource files.
 */
public class TransitionInflater {

    private static final Class<?>[] CONSTRUCTOR_SIGNATURE =
            new Class<?>[]{Context.class, AttributeSet.class};
    private static final ArrayMap<String, Constructor<?>> CONSTRUCTORS = new ArrayMap<>();

    private final Context mContext;

    private TransitionInflater(@NonNull Context context) {
        mContext = context;
    }

    /**
     * Obtains the TransitionInflater from the given context.
     */
    @NonNull
    public static TransitionInflater from(@NonNull Context context) {
        return new TransitionInflater(context);
    }

    /**
     * Loads a {@link Transition} object from a resource
     *
     * @param resource The resource id of the transition to load
     * @return The loaded Transition object
     * @throws android.content.res.Resources.NotFoundException when the
     *                                                         transition cannot be loaded
     */
    public Transition inflateTransition(int resource) {
        XmlResourceParser parser = mContext.getResources().getXml(resource);
        try {
            return createTransitionFromXml(parser, Xml.asAttributeSet(parser), null);
        } catch (XmlPullParserException e) {
            throw new InflateException(e.getMessage(), e);
        } catch (IOException e) {
            throw new InflateException(
                    parser.getPositionDescription() + ": " + e.getMessage(), e);
        } finally {
            parser.close();
        }
    }

    /**
     * Loads a {@link TransitionManager} object from a resource
     *
     * @param resource The resource id of the transition manager to load
     * @return The loaded TransitionManager object
     * @throws android.content.res.Resources.NotFoundException when the
     *                                                         transition manager cannot be loaded
     */
    public TransitionManager inflateTransitionManager(int resource, ViewGroup sceneRoot) {
        XmlResourceParser parser = mContext.getResources().getXml(resource);
        try {
            return createTransitionManagerFromXml(parser, Xml.asAttributeSet(parser), sceneRoot);
        } catch (XmlPullParserException e) {
            InflateException ex = new InflateException(e.getMessage());
            ex.initCause(e);
            throw ex;
        } catch (IOException e) {
            InflateException ex = new InflateException(
                    parser.getPositionDescription()
                            + ": " + e.getMessage());
            ex.initCause(e);
            throw ex;
        } finally {
            parser.close();
        }
    }

    //
    // Transition loading
    //
    private Transition createTransitionFromXml(XmlPullParser parser,
            AttributeSet attrs, Transition parent)
            throws XmlPullParserException, IOException {

        Transition transition = null;

        // Make sure we are on a start tag.
        int type;
        int depth = parser.getDepth();

        TransitionSet transitionSet = (parent instanceof TransitionSet)
                ? (TransitionSet) parent : null;

        while (((type = parser.next()) != XmlPullParser.END_TAG || parser.getDepth() > depth)
                && type != XmlPullParser.END_DOCUMENT) {

            if (type != XmlPullParser.START_TAG) {
                continue;
            }

            String name = parser.getName();
            if ("fade".equals(name)) {
                transition = new Fade(mContext, attrs);
            } else if ("changeBounds".equals(name)) {
                transition = new ChangeBounds(mContext, attrs);
            } else if ("slide".equals(name)) {
                transition = new Slide(mContext, attrs);
            } else if ("explode".equals(name)) {
                transition = new Explode(mContext, attrs);
            } else if ("changeImageTransform".equals(name)) {
                transition = new ChangeImageTransform(mContext, attrs);
            } else if ("changeTransform".equals(name)) {
                transition = new ChangeTransform(mContext, attrs);
            } else if ("changeClipBounds".equals(name)) {
                transition = new ChangeClipBounds(mContext, attrs);
            } else if ("autoTransition".equals(name)) {
                transition = new AutoTransition(mContext, attrs);
            } else if ("changeScroll".equals(name)) {
                transition = new ChangeScroll(mContext, attrs);
            } else if ("transitionSet".equals(name)) {
                transition = new TransitionSet(mContext, attrs);
            } else if ("transition".equals(name)) {
                transition = (Transition) createCustom(attrs, Transition.class, "transition");
            } else if ("targets".equals(name)) {
                getTargetIds(parser, attrs, parent);
            } else if ("arcMotion".equals(name)) {
                if (parent == null) {
                    throw new RuntimeException("Invalid use of arcMotion element");
                }
                parent.setPathMotion(new ArcMotion(mContext, attrs));
            } else if ("pathMotion".equals(name)) {
                if (parent == null) {
                    throw new RuntimeException("Invalid use of pathMotion element");
                }
                parent.setPathMotion((PathMotion) createCustom(attrs, PathMotion.class,
                        "pathMotion"));
            } else if ("patternPathMotion".equals(name)) {
                if (parent == null) {
                    throw new RuntimeException("Invalid use of patternPathMotion element");
                }
                parent.setPathMotion(new PatternPathMotion(mContext, attrs));
            } else {
                throw new RuntimeException("Unknown scene name: " + parser.getName());
            }
            if (transition != null) {
                if (!parser.isEmptyElementTag()) {
                    createTransitionFromXml(parser, attrs, transition);
                }
                if (transitionSet != null) {
                    transitionSet.addTransition(transition);
                    transition = null;
                } else if (parent != null) {
                    throw new InflateException("Could not add transition to another transition.");
                }
            }
        }

        return transition;
    }

    private Object createCustom(AttributeSet attrs, Class<?> expectedType, String tag) {
        String className = attrs.getAttributeValue(null, "class");

        if (className == null) {
            throw new InflateException(tag + " tag must have a 'class' attribute");
        }

        try {
            synchronized (CONSTRUCTORS) {
                Constructor<?> constructor = CONSTRUCTORS.get(className);
                if (constructor == null) {
                    @SuppressWarnings("unchecked")
                    Class<?> c = Class.forName(className, false, mContext.getClassLoader())
                            .asSubclass(expectedType);
                    if (c != null) {
                        constructor = c.getConstructor(CONSTRUCTOR_SIGNATURE);
                        constructor.setAccessible(true);
                        CONSTRUCTORS.put(className, constructor);
                    }
                }
                //noinspection ConstantConditions
                return constructor.newInstance(mContext, attrs);
            }
        } catch (Exception e) {
            throw new InflateException("Could not instantiate " + expectedType + " class "
                    + className, e);
        }
    }

    @SuppressLint("RestrictedApi") // remove once core lib would be released with the new
    // LIBRARY_GROUP_PREFIX restriction. tracking in b/127286008
    private void getTargetIds(XmlPullParser parser,
            AttributeSet attrs, Transition transition) throws XmlPullParserException, IOException {

        // Make sure we are on a start tag.
        int type;
        int depth = parser.getDepth();

        while (((type = parser.next()) != XmlPullParser.END_TAG || parser.getDepth() > depth)
                && type != XmlPullParser.END_DOCUMENT) {

            if (type != XmlPullParser.START_TAG) {
                continue;
            }

            String name = parser.getName();
            if (name.equals("target")) {
                TypedArray a = mContext.obtainStyledAttributes(attrs, Styleable.TRANSITION_TARGET);
                int id = TypedArrayUtils.getNamedResourceId(a, parser, "targetId",
                        Styleable.TransitionTarget.TARGET_ID, 0);
                String transitionName;
                if (id != 0) {
                    transition.addTarget(id);
                } else if ((id = TypedArrayUtils.getNamedResourceId(a, parser, "excludeId",
                        Styleable.TransitionTarget.EXCLUDE_ID, 0)) != 0) {
                    transition.excludeTarget(id, true);
                } else if ((transitionName = TypedArrayUtils.getNamedString(a, parser, "targetName",
                        Styleable.TransitionTarget.TARGET_NAME)) != null) {
                    transition.addTarget(transitionName);
                } else if ((transitionName = TypedArrayUtils.getNamedString(a, parser,
                        "excludeName", Styleable.TransitionTarget.EXCLUDE_NAME)) != null) {
                    transition.excludeTarget(transitionName, true);
                } else {
                    String className = TypedArrayUtils.getNamedString(a, parser,
                            "excludeClass", Styleable.TransitionTarget.EXCLUDE_CLASS);
                    try {
                        if (className != null) {
                            Class<?> clazz = Class.forName(className);
                            transition.excludeTarget(clazz, true);
                        } else if ((className = TypedArrayUtils.getNamedString(a, parser,
                                "targetClass", Styleable.TransitionTarget.TARGET_CLASS)) != null) {
                            Class<?> clazz = Class.forName(className);
                            transition.addTarget(clazz);
                        }
                    } catch (ClassNotFoundException e) {
                        a.recycle();
                        throw new RuntimeException("Could not create " + className, e);
                    }
                }
                a.recycle();
            } else {
                throw new RuntimeException("Unknown scene name: " + parser.getName());
            }
        }
    }

    //
    // TransitionManager loading
    //

    private TransitionManager createTransitionManagerFromXml(XmlPullParser parser,
            AttributeSet attrs, ViewGroup sceneRoot) throws XmlPullParserException, IOException {

        // Make sure we are on a start tag.
        int type;
        int depth = parser.getDepth();
        TransitionManager transitionManager = null;

        while (((type = parser.next()) != XmlPullParser.END_TAG || parser.getDepth() > depth)
                && type != XmlPullParser.END_DOCUMENT) {

            if (type != XmlPullParser.START_TAG) {
                continue;
            }

            String name = parser.getName();
            if (name.equals("transitionManager")) {
                transitionManager = new TransitionManager();
            } else if (name.equals("transition") && (transitionManager != null)) {
                loadTransition(attrs, parser, sceneRoot, transitionManager);
            } else {
                throw new RuntimeException("Unknown scene name: " + parser.getName());
            }
        }
        return transitionManager;
    }

    @SuppressLint("RestrictedApi") // remove once core lib would be released with the new
    // LIBRARY_GROUP_PREFIX restriction. tracking in b/127286008
    private void loadTransition(AttributeSet attrs, XmlPullParser parser, ViewGroup sceneRoot,
            TransitionManager transitionManager) throws Resources.NotFoundException {

        TypedArray a = mContext.obtainStyledAttributes(attrs, Styleable.TRANSITION_MANAGER);
        int transitionId = TypedArrayUtils.getNamedResourceId(a, parser, "transition",
                Styleable.TransitionManager.TRANSITION, -1);
        int fromId = TypedArrayUtils.getNamedResourceId(a, parser, "fromScene",
                Styleable.TransitionManager.FROM_SCENE, -1);
        Scene fromScene = (fromId < 0) ? null : Scene.getSceneForLayout(sceneRoot, fromId,
                mContext);
        int toId = TypedArrayUtils.getNamedResourceId(a, parser, "toScene",
                Styleable.TransitionManager.TO_SCENE, -1);
        Scene toScene = (toId < 0) ? null : Scene.getSceneForLayout(sceneRoot, toId, mContext);

        if (transitionId >= 0) {
            Transition transition = inflateTransition(transitionId);
            if (transition != null) {
                if (toScene == null) {
                    throw new RuntimeException("No toScene for transition ID " + transitionId);
                }
                if (fromScene == null) {
                    transitionManager.setTransition(toScene, transition);
                } else {
                    transitionManager.setTransition(fromScene, toScene, transition);
                }
            }
        }
        a.recycle();
    }

}