/*
 * Copyright (C) 2014 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 android.app;

import android.content.Context;
import android.graphics.Matrix;
import android.graphics.Rect;
import android.graphics.RectF;
import android.os.Bundle;
import android.os.Handler;
import android.os.Parcelable;
import android.os.ResultReceiver;
import android.transition.Transition;
import android.transition.TransitionListenerAdapter;
import android.transition.TransitionSet;
import android.transition.Visibility;
import android.util.ArrayMap;
import android.util.ArraySet;
import android.view.GhostView;
import android.view.View;
import android.view.ViewGroup;
import android.view.ViewGroupOverlay;
import android.view.ViewParent;
import android.view.ViewRootImpl;
import android.view.ViewTreeObserver;
import android.view.Window;
import android.widget.ImageView;

import com.android.internal.view.OneShotPreDrawListener;

import java.util.ArrayList;
import java.util.Collection;

Base class for ExitTransitionCoordinator and EnterTransitionCoordinator, classes
that manage activity transitions and the communications coordinating them between
Activities. The ExitTransitionCoordinator is created in the
ActivityOptions#makeSceneTransitionAnimation. The EnterTransitionCoordinator
is created by ActivityOptions#createEnterActivityTransition by Activity when the window is
attached.
Typical startActivity goes like this:
1) ExitTransitionCoordinator created with ActivityOptions#makeSceneTransitionAnimation
2) Activity#startActivity called and that calls startExit() through
   ActivityOptions#dispatchStartExit
   - Exit transition starts by setting transitioning Views to INVISIBLE
3) Launched Activity starts, creating an EnterTransitionCoordinator.
   - The Window is made translucent
   - The Window background alpha is set to 0
   - The transitioning views are made INVISIBLE
   - MSG_SET_LISTENER is sent back to the ExitTransitionCoordinator.
4) The shared element transition completes.
   - MSG_TAKE_SHARED_ELEMENTS is sent to the EnterTransitionCoordinator
5) The MSG_TAKE_SHARED_ELEMENTS is received by the EnterTransitionCoordinator.
   - Shared elements are made VISIBLE
   - Shared elements positions and size are set to match the end state of the calling
     Activity.
   - The shared element transition is started
   - If the window allows overlapping transitions, the views transition is started by setting
     the entering Views to VISIBLE and the background alpha is animated to opaque.
   - MSG_HIDE_SHARED_ELEMENTS is sent to the ExitTransitionCoordinator
6) MSG_HIDE_SHARED_ELEMENTS is received by the ExitTransitionCoordinator
   - The shared elements are made INVISIBLE
7) The exit transition completes in the calling Activity.
   - MSG_EXIT_TRANSITION_COMPLETE is sent to the EnterTransitionCoordinator.
8) The MSG_EXIT_TRANSITION_COMPLETE is received by the EnterTransitionCoordinator.
   - If the window doesn't allow overlapping enter transitions, the enter transition is started
     by setting entering views to VISIBLE and the background is animated to opaque.
9) The background opacity animation completes.
   - The window is made opaque
10) The calling Activity gets an onStop() call
   - onActivityStopped() is called and all exited Views are made VISIBLE.
Typical finishAfterTransition goes like this:
1) finishAfterTransition() creates an ExitTransitionCoordinator and calls startExit()
   - The Window start transitioning to Translucent with a new ActivityOptions.
   - If no background exists, a black background is substituted
   - The shared elements in the scene are matched against those shared elements
     that were sent by comparing the names.
   - The exit transition is started by setting Views to INVISIBLE.
2) The ActivityOptions is received by the Activity and an EnterTransitionCoordinator is created.
   - All transitioning views are made VISIBLE to reverse what was done when onActivityStopped()
     was called
3) The Window is made translucent and a callback is received
   - The background alpha is animated to 0
4) The background alpha animation completes
5) The shared element transition completes
   - After both 4 & 5 complete, MSG_TAKE_SHARED_ELEMENTS is sent to the
     EnterTransitionCoordinator
6) MSG_TAKE_SHARED_ELEMENTS is received by EnterTransitionCoordinator
   - Shared elements are made VISIBLE
   - Shared elements positions and size are set to match the end state of the calling
     Activity.
   - The shared element transition is started
   - If the window allows overlapping transitions, the views transition is started by setting
     the entering Views to VISIBLE.
   - MSG_HIDE_SHARED_ELEMENTS is sent to the ExitTransitionCoordinator
7) MSG_HIDE_SHARED_ELEMENTS is received by the ExitTransitionCoordinator
   - The shared elements are made INVISIBLE
8) The exit transition completes in the finishing Activity.
   - MSG_EXIT_TRANSITION_COMPLETE is sent to the EnterTransitionCoordinator.
   - finish() is called on the exiting Activity
9) The MSG_EXIT_TRANSITION_COMPLETE is received by the EnterTransitionCoordinator.
   - If the window doesn't allow overlapping enter transitions, the enter transition is started
     by setting entering views to VISIBLE.
/**
 * Base class for ExitTransitionCoordinator and EnterTransitionCoordinator, classes
 * that manage activity transitions and the communications coordinating them between
 * Activities. The ExitTransitionCoordinator is created in the
 * ActivityOptions#makeSceneTransitionAnimation. The EnterTransitionCoordinator
 * is created by ActivityOptions#createEnterActivityTransition by Activity when the window is
 * attached.
 *
 * Typical startActivity goes like this:
 * 1) ExitTransitionCoordinator created with ActivityOptions#makeSceneTransitionAnimation
 * 2) Activity#startActivity called and that calls startExit() through
 *    ActivityOptions#dispatchStartExit
 *    - Exit transition starts by setting transitioning Views to INVISIBLE
 * 3) Launched Activity starts, creating an EnterTransitionCoordinator.
 *    - The Window is made translucent
 *    - The Window background alpha is set to 0
 *    - The transitioning views are made INVISIBLE
 *    - MSG_SET_LISTENER is sent back to the ExitTransitionCoordinator.
 * 4) The shared element transition completes.
 *    - MSG_TAKE_SHARED_ELEMENTS is sent to the EnterTransitionCoordinator
 * 5) The MSG_TAKE_SHARED_ELEMENTS is received by the EnterTransitionCoordinator.
 *    - Shared elements are made VISIBLE
 *    - Shared elements positions and size are set to match the end state of the calling
 *      Activity.
 *    - The shared element transition is started
 *    - If the window allows overlapping transitions, the views transition is started by setting
 *      the entering Views to VISIBLE and the background alpha is animated to opaque.
 *    - MSG_HIDE_SHARED_ELEMENTS is sent to the ExitTransitionCoordinator
 * 6) MSG_HIDE_SHARED_ELEMENTS is received by the ExitTransitionCoordinator
 *    - The shared elements are made INVISIBLE
 * 7) The exit transition completes in the calling Activity.
 *    - MSG_EXIT_TRANSITION_COMPLETE is sent to the EnterTransitionCoordinator.
 * 8) The MSG_EXIT_TRANSITION_COMPLETE is received by the EnterTransitionCoordinator.
 *    - If the window doesn't allow overlapping enter transitions, the enter transition is started
 *      by setting entering views to VISIBLE and the background is animated to opaque.
 * 9) The background opacity animation completes.
 *    - The window is made opaque
 * 10) The calling Activity gets an onStop() call
 *    - onActivityStopped() is called and all exited Views are made VISIBLE.
 *
 * Typical finishAfterTransition goes like this:
 * 1) finishAfterTransition() creates an ExitTransitionCoordinator and calls startExit()
 *    - The Window start transitioning to Translucent with a new ActivityOptions.
 *    - If no background exists, a black background is substituted
 *    - The shared elements in the scene are matched against those shared elements
 *      that were sent by comparing the names.
 *    - The exit transition is started by setting Views to INVISIBLE.
 * 2) The ActivityOptions is received by the Activity and an EnterTransitionCoordinator is created.
 *    - All transitioning views are made VISIBLE to reverse what was done when onActivityStopped()
 *      was called
 * 3) The Window is made translucent and a callback is received
 *    - The background alpha is animated to 0
 * 4) The background alpha animation completes
 * 5) The shared element transition completes
 *    - After both 4 & 5 complete, MSG_TAKE_SHARED_ELEMENTS is sent to the
 *      EnterTransitionCoordinator
 * 6) MSG_TAKE_SHARED_ELEMENTS is received by EnterTransitionCoordinator
 *    - Shared elements are made VISIBLE
 *    - Shared elements positions and size are set to match the end state of the calling
 *      Activity.
 *    - The shared element transition is started
 *    - If the window allows overlapping transitions, the views transition is started by setting
 *      the entering Views to VISIBLE.
 *    - MSG_HIDE_SHARED_ELEMENTS is sent to the ExitTransitionCoordinator
 * 7) MSG_HIDE_SHARED_ELEMENTS is received by the ExitTransitionCoordinator
 *    - The shared elements are made INVISIBLE
 * 8) The exit transition completes in the finishing Activity.
 *    - MSG_EXIT_TRANSITION_COMPLETE is sent to the EnterTransitionCoordinator.
 *    - finish() is called on the exiting Activity
 * 9) The MSG_EXIT_TRANSITION_COMPLETE is received by the EnterTransitionCoordinator.
 *    - If the window doesn't allow overlapping enter transitions, the enter transition is started
 *      by setting entering views to VISIBLE.
 */
abstract class ActivityTransitionCoordinator extends ResultReceiver {
    private static final String TAG = "ActivityTransitionCoordinator";

    
For Activity transitions, the called Activity's listener to receive calls
when transitions complete.
/**
     * For Activity transitions, the called Activity's listener to receive calls
     * when transitions complete.
     */
    static final String KEY_REMOTE_RECEIVER = "android:remoteReceiver";

    protected static final String KEY_SCREEN_LEFT = "shared_element:screenLeft";
    protected static final String KEY_SCREEN_TOP = "shared_element:screenTop";
    protected static final String KEY_SCREEN_RIGHT = "shared_element:screenRight";
    protected static final String KEY_SCREEN_BOTTOM= "shared_element:screenBottom";
    protected static final String KEY_TRANSLATION_Z = "shared_element:translationZ";
    protected static final String KEY_SNAPSHOT = "shared_element:bitmap";
    protected static final String KEY_SCALE_TYPE = "shared_element:scaleType";
    protected static final String KEY_IMAGE_MATRIX = "shared_element:imageMatrix";
    protected static final String KEY_ELEVATION = "shared_element:elevation";

    protected static final ImageView.ScaleType[] SCALE_TYPE_VALUES = ImageView.ScaleType.values();

    
Sent by the exiting coordinator (either EnterTransitionCoordinator
or ExitTransitionCoordinator) after the shared elements have
become stationary (shared element transition completes). This tells
the remote coordinator to take control of the shared elements and
that animations may begin. The remote Activity won't start entering
until this message is received, but may wait for
MSG_EXIT_TRANSITION_COMPLETE if allowOverlappingTransitions() is true.
/**
     * Sent by the exiting coordinator (either EnterTransitionCoordinator
     * or ExitTransitionCoordinator) after the shared elements have
     * become stationary (shared element transition completes). This tells
     * the remote coordinator to take control of the shared elements and
     * that animations may begin. The remote Activity won't start entering
     * until this message is received, but may wait for
     * MSG_EXIT_TRANSITION_COMPLETE if allowOverlappingTransitions() is true.
     */
    public static final int MSG_SET_REMOTE_RECEIVER = 100;

    
Sent by the entering coordinator to tell the exiting coordinator
to hide its shared elements after it has started its shared
element transition. This is temporary until the
interlock of shared elements is figured out.
/**
     * Sent by the entering coordinator to tell the exiting coordinator
     * to hide its shared elements after it has started its shared
     * element transition. This is temporary until the
     * interlock of shared elements is figured out.
     */
    public static final int MSG_HIDE_SHARED_ELEMENTS = 101;

    
Sent by the exiting coordinator (either EnterTransitionCoordinator
or ExitTransitionCoordinator) after the shared elements have
become stationary (shared element transition completes). This tells
the remote coordinator to take control of the shared elements and
that animations may begin. The remote Activity won't start entering
until this message is received, but may wait for
MSG_EXIT_TRANSITION_COMPLETE if allowOverlappingTransitions() is true.
/**
     * Sent by the exiting coordinator (either EnterTransitionCoordinator
     * or ExitTransitionCoordinator) after the shared elements have
     * become stationary (shared element transition completes). This tells
     * the remote coordinator to take control of the shared elements and
     * that animations may begin. The remote Activity won't start entering
     * until this message is received, but may wait for
     * MSG_EXIT_TRANSITION_COMPLETE if allowOverlappingTransitions() is true.
     */
    public static final int MSG_TAKE_SHARED_ELEMENTS = 103;

    
Sent by the exiting coordinator (either
EnterTransitionCoordinator or ExitTransitionCoordinator) after
the exiting Views have finished leaving the scene. This will
be ignored if allowOverlappingTransitions() is true on the
remote coordinator. If it is false, it will trigger the enter
transition to start.
/**
     * Sent by the exiting coordinator (either
     * EnterTransitionCoordinator or ExitTransitionCoordinator) after
     * the exiting Views have finished leaving the scene. This will
     * be ignored if allowOverlappingTransitions() is true on the
     * remote coordinator. If it is false, it will trigger the enter
     * transition to start.
     */
    public static final int MSG_EXIT_TRANSITION_COMPLETE = 104;

    
Sent by Activity#startActivity to begin the exit transition.
/**
     * Sent by Activity#startActivity to begin the exit transition.
     */
    public static final int MSG_START_EXIT_TRANSITION = 105;

    
It took too long for a message from the entering Activity, so we canceled the transition.
/**
     * It took too long for a message from the entering Activity, so we canceled the transition.
     */
    public static final int MSG_CANCEL = 106;

    
When returning, this is the destination location for the shared element.
/**
     * When returning, this is the destination location for the shared element.
     */
    public static final int MSG_SHARED_ELEMENT_DESTINATION = 107;

    private Window mWindow;
    final protected ArrayList<String> mAllSharedElementNames;
    final protected ArrayList<View> mSharedElements = new ArrayList<View>();
    final protected ArrayList<String> mSharedElementNames = new ArrayList<String>();
    protected ArrayList<View> mTransitioningViews = new ArrayList<View>();
    protected SharedElementCallback mListener;
    protected ResultReceiver mResultReceiver;
    final private FixedEpicenterCallback mEpicenterCallback = new FixedEpicenterCallback();
    final protected boolean mIsReturning;
    private Runnable mPendingTransition;
    private boolean mIsStartingTransition;
    private ArrayList<GhostViewListeners> mGhostViewListeners =
            new ArrayList<GhostViewListeners>();
    private ArrayMap<View, Float> mOriginalAlphas = new ArrayMap<View, Float>();
    private ArrayList<Matrix> mSharedElementParentMatrices;
    private boolean mSharedElementTransitionComplete;
    private boolean mViewsTransitionComplete;
    private boolean mBackgroundAnimatorComplete;
    private ArrayList<View> mStrippedTransitioningViews = new ArrayList<>();

    public ActivityTransitionCoordinator(Window window,
            ArrayList<String> allSharedElementNames,
            SharedElementCallback listener, boolean isReturning) {
        super(new Handler());
        mWindow = window;
        mListener = listener;
        mAllSharedElementNames = allSharedElementNames;
        mIsReturning = isReturning;
    }

    protected void viewsReady(ArrayMap<String, View> sharedElements) {
        sharedElements.retainAll(mAllSharedElementNames);
        if (mListener != null) {
            mListener.onMapSharedElements(mAllSharedElementNames, sharedElements);
        }
        setSharedElements(sharedElements);
        if (getViewsTransition() != null && mTransitioningViews != null) {
            ViewGroup decorView = getDecor();
            if (decorView != null) {
                decorView.captureTransitioningViews(mTransitioningViews);
            }
            mTransitioningViews.removeAll(mSharedElements);
        }
        setEpicenter();
    }

    
Iterates over the shared elements and adds them to the members in order.
Shared elements that are nested in other shared elements are placed after the
elements that they are nested in. This means that layout ordering can be done
from first to last.
Params:
sharedElements – The map of transition names to shared elements to set into
                      the member fields./**
     * Iterates over the shared elements and adds them to the members in order.
     * Shared elements that are nested in other shared elements are placed after the
     * elements that they are nested in. This means that layout ordering can be done
     * from first to last.
     *
     * @param sharedElements The map of transition names to shared elements to set into
     *                       the member fields.
     */
    private void setSharedElements(ArrayMap<String, View> sharedElements) {
        boolean isFirstRun = true;
        while (!sharedElements.isEmpty()) {
            final int numSharedElements = sharedElements.size();
            for (int i = numSharedElements - 1; i >= 0; i--) {
                final View view = sharedElements.valueAt(i);
                final String name = sharedElements.keyAt(i);
                if (isFirstRun && (view == null || !view.isAttachedToWindow() || name == null)) {
                    sharedElements.removeAt(i);
                } else if (!isNested(view, sharedElements)) {
                    mSharedElementNames.add(name);
                    mSharedElements.add(view);
                    sharedElements.removeAt(i);
                }
            }
            isFirstRun = false;
        }
    }

    
Returns true when view is nested in any of the values of sharedElements.
/**
     * Returns true when view is nested in any of the values of sharedElements.
     */
    private static boolean isNested(View view, ArrayMap<String, View> sharedElements) {
        ViewParent parent = view.getParent();
        boolean isNested = false;
        while (parent instanceof View) {
            View parentView = (View) parent;
            if (sharedElements.containsValue(parentView)) {
                isNested = true;
                break;
            }
            parent = parentView.getParent();
        }
        return isNested;
    }

    protected void stripOffscreenViews() {
        if (mTransitioningViews == null) {
            return;
        }
        Rect r = new Rect();
        for (int i = mTransitioningViews.size() - 1; i >= 0; i--) {
            View view = mTransitioningViews.get(i);
            if (!view.getGlobalVisibleRect(r)) {
                mTransitioningViews.remove(i);
                mStrippedTransitioningViews.add(view);
            }
        }
    }

    protected Window getWindow() {
        return mWindow;
    }

    public ViewGroup getDecor() {
        return (mWindow == null) ? null : (ViewGroup) mWindow.getDecorView();
    }

    
Sets the transition epicenter to the position of the first shared element.
/**
     * Sets the transition epicenter to the position of the first shared element.
     */
    protected void setEpicenter() {
        View epicenter = null;
        if (!mAllSharedElementNames.isEmpty() && !mSharedElementNames.isEmpty()) {
            int index = mSharedElementNames.indexOf(mAllSharedElementNames.get(0));
            if (index >= 0) {
                epicenter = mSharedElements.get(index);
            }
        }
        setEpicenter(epicenter);
    }

    private void setEpicenter(View view) {
        if (view == null) {
            mEpicenterCallback.setEpicenter(null);
        } else {
            Rect epicenter = new Rect();
            view.getBoundsOnScreen(epicenter);
            mEpicenterCallback.setEpicenter(epicenter);
        }
    }

    public ArrayList<String> getAcceptedNames() {
        return mSharedElementNames;
    }

    public ArrayList<String> getMappedNames() {
        ArrayList<String> names = new ArrayList<String>(mSharedElements.size());
        for (int i = 0; i < mSharedElements.size(); i++) {
            names.add(mSharedElements.get(i).getTransitionName());
        }
        return names;
    }

    public ArrayList<View> copyMappedViews() {
        return new ArrayList<View>(mSharedElements);
    }

    public ArrayList<String> getAllSharedElementNames() { return mAllSharedElementNames; }

    protected Transition setTargets(Transition transition, boolean add) {
        if (transition == null || (add &&
                (mTransitioningViews == null || mTransitioningViews.isEmpty()))) {
            return null;
        }
        // Add the targets to a set containing transition so that transition
        // remains unaffected. We don't want to modify the targets of transition itself.
        TransitionSet set = new TransitionSet();
        if (mTransitioningViews != null) {
            for (int i = mTransitioningViews.size() - 1; i >= 0; i--) {
                View view = mTransitioningViews.get(i);
                if (add) {
                    set.addTarget(view);
                } else {
                    set.excludeTarget(view, true);
                }
            }
        }
        if (mStrippedTransitioningViews != null) {
            for (int i = mStrippedTransitioningViews.size() - 1; i >= 0; i--) {
                View view = mStrippedTransitioningViews.get(i);
                set.excludeTarget(view, true);
            }
        }
        // By adding the transition after addTarget, we prevent addTarget from
        // affecting transition.
        set.addTransition(transition);

        if (!add && mTransitioningViews != null && !mTransitioningViews.isEmpty()) {
            // Allow children of excluded transitioning views, but not the views themselves
            set = new TransitionSet().addTransition(set);
        }

        return set;
    }

    protected Transition configureTransition(Transition transition,
            boolean includeTransitioningViews) {
        if (transition != null) {
            transition = transition.clone();
            transition.setEpicenterCallback(mEpicenterCallback);
            transition = setTargets(transition, includeTransitioningViews);
        }
        noLayoutSuppressionForVisibilityTransitions(transition);
        return transition;
    }

    
Looks through the transition to see which Views have been included and which have been excluded. views will be modified to contain only those Views that are included in the transition. If transition is a TransitionSet, it will search through all contained Transitions to find targeted Views. 
Params:
transition – The transition to look through for inclusion of Views
views – The list of Views that are to be checked for inclusion. Will be modified
             to remove all excluded Views, possibly leaving an empty list./**
     * Looks through the transition to see which Views have been included and which have been
     * excluded. {@code views} will be modified to contain only those Views that are included
     * in the transition. If {@code transition} is a TransitionSet, it will search through all
     * contained Transitions to find targeted Views.
     *
     * @param transition The transition to look through for inclusion of Views
     * @param views The list of Views that are to be checked for inclusion. Will be modified
     *              to remove all excluded Views, possibly leaving an empty list.
     */
    protected static void removeExcludedViews(Transition transition, ArrayList<View> views) {
        ArraySet<View> included = new ArraySet<>();
        findIncludedViews(transition, views, included);
        views.clear();
        views.addAll(included);
    }

    
Looks through the transition to see which Views have been included. Only views will be examined for inclusion. If transition is a TransitionSet, it will search through all contained Transitions to find targeted Views. 
Params:
transition – The transition to look through for inclusion of Views
views – The list of Views that are to be checked for inclusion.
included – Modified to contain all Views in views that have at least one Transition
                that affects it./**
     * Looks through the transition to see which Views have been included. Only {@code views}
     * will be examined for inclusion. If {@code transition} is a TransitionSet, it will search
     * through all contained Transitions to find targeted Views.
     *
     * @param transition The transition to look through for inclusion of Views
     * @param views The list of Views that are to be checked for inclusion.
     * @param included Modified to contain all Views in views that have at least one Transition
     *                 that affects it.
     */
    private static void findIncludedViews(Transition transition, ArrayList<View> views,
            ArraySet<View> included) {
        if (transition instanceof TransitionSet) {
            TransitionSet set = (TransitionSet) transition;
            ArrayList<View> includedViews = new ArrayList<>();
            final int numViews = views.size();
            for (int i = 0; i < numViews; i++) {
                final View view = views.get(i);
                if (transition.isValidTarget(view)) {
                    includedViews.add(view);
                }
            }
            final int count = set.getTransitionCount();
            for (int i = 0; i < count; i++) {
                findIncludedViews(set.getTransitionAt(i), includedViews, included);
            }
        } else {
            final int numViews = views.size();
            for (int i = 0; i < numViews; i++) {
                final View view = views.get(i);
                if (transition.isValidTarget(view)) {
                    included.add(view);
                }
            }
        }
    }

    protected static Transition mergeTransitions(Transition transition1, Transition transition2) {
        if (transition1 == null) {
            return transition2;
        } else if (transition2 == null) {
            return transition1;
        } else {
            TransitionSet transitionSet = new TransitionSet();
            transitionSet.addTransition(transition1);
            transitionSet.addTransition(transition2);
            return transitionSet;
        }
    }

    protected ArrayMap<String, View> mapSharedElements(ArrayList<String> accepted,
            ArrayList<View> localViews) {
        ArrayMap<String, View> sharedElements = new ArrayMap<String, View>();
        if (accepted != null) {
            for (int i = 0; i < accepted.size(); i++) {
                sharedElements.put(accepted.get(i), localViews.get(i));
            }
        } else {
            ViewGroup decorView = getDecor();
            if (decorView != null) {
                decorView.findNamedViews(sharedElements);
            }
        }
        return sharedElements;
    }

    protected void setResultReceiver(ResultReceiver resultReceiver) {
        mResultReceiver = resultReceiver;
    }

    protected abstract Transition getViewsTransition();

    private void setSharedElementState(View view, String name, Bundle transitionArgs,
            Matrix tempMatrix, RectF tempRect, int[] decorLoc) {
        Bundle sharedElementBundle = transitionArgs.getBundle(name);
        if (sharedElementBundle == null) {
            return;
        }

        if (view instanceof ImageView) {
            int scaleTypeInt = sharedElementBundle.getInt(KEY_SCALE_TYPE, -1);
            if (scaleTypeInt >= 0) {
                ImageView imageView = (ImageView) view;
                ImageView.ScaleType scaleType = SCALE_TYPE_VALUES[scaleTypeInt];
                imageView.setScaleType(scaleType);
                if (scaleType == ImageView.ScaleType.MATRIX) {
                    float[] matrixValues = sharedElementBundle.getFloatArray(KEY_IMAGE_MATRIX);
                    tempMatrix.setValues(matrixValues);
                    imageView.setImageMatrix(tempMatrix);
                }
            }
        }

        float z = sharedElementBundle.getFloat(KEY_TRANSLATION_Z);
        view.setTranslationZ(z);
        float elevation = sharedElementBundle.getFloat(KEY_ELEVATION);
        view.setElevation(elevation);

        float left = sharedElementBundle.getFloat(KEY_SCREEN_LEFT);
        float top = sharedElementBundle.getFloat(KEY_SCREEN_TOP);
        float right = sharedElementBundle.getFloat(KEY_SCREEN_RIGHT);
        float bottom = sharedElementBundle.getFloat(KEY_SCREEN_BOTTOM);

        if (decorLoc != null) {
            left -= decorLoc[0];
            top -= decorLoc[1];
            right -= decorLoc[0];
            bottom -= decorLoc[1];
        } else {
            // Find the location in the view's parent
            getSharedElementParentMatrix(view, tempMatrix);
            tempRect.set(left, top, right, bottom);
            tempMatrix.mapRect(tempRect);

            float leftInParent = tempRect.left;
            float topInParent = tempRect.top;

            // Find the size of the view
            view.getInverseMatrix().mapRect(tempRect);
            float width = tempRect.width();
            float height = tempRect.height();

            // Now determine the offset due to view transform:
            view.setLeft(0);
            view.setTop(0);
            view.setRight(Math.round(width));
            view.setBottom(Math.round(height));
            tempRect.set(0, 0, width, height);
            view.getMatrix().mapRect(tempRect);

            left = leftInParent - tempRect.left;
            top = topInParent - tempRect.top;
            right = left + width;
            bottom = top + height;
        }

        int x = Math.round(left);
        int y = Math.round(top);
        int width = Math.round(right) - x;
        int height = Math.round(bottom) - y;
        int widthSpec = View.MeasureSpec.makeMeasureSpec(width, View.MeasureSpec.EXACTLY);
        int heightSpec = View.MeasureSpec.makeMeasureSpec(height, View.MeasureSpec.EXACTLY);
        view.measure(widthSpec, heightSpec);

        view.layout(x, y, x + width, y + height);
    }

    private void setSharedElementMatrices() {
        int numSharedElements = mSharedElements.size();
        if (numSharedElements > 0) {
            mSharedElementParentMatrices = new ArrayList<Matrix>(numSharedElements);
        }
        for (int i = 0; i < numSharedElements; i++) {
            View view = mSharedElements.get(i);

            // Find the location in the view's parent
            ViewGroup parent = (ViewGroup) view.getParent();
            Matrix matrix = new Matrix();
            if (parent != null) {
                parent.transformMatrixToLocal(matrix);
                matrix.postTranslate(parent.getScrollX(), parent.getScrollY());
            }
            mSharedElementParentMatrices.add(matrix);
        }
    }

    private void getSharedElementParentMatrix(View view, Matrix matrix) {
        final int index = mSharedElementParentMatrices == null ? -1
                : mSharedElements.indexOf(view);
        if (index < 0) {
            matrix.reset();
            ViewParent viewParent = view.getParent();
            if (viewParent instanceof ViewGroup) {
                // Find the location in the view's parent
                ViewGroup parent = (ViewGroup) viewParent;
                parent.transformMatrixToLocal(matrix);
                matrix.postTranslate(parent.getScrollX(), parent.getScrollY());
            }
        } else {
            // The indices of mSharedElementParentMatrices matches the
            // mSharedElement matrices.
            Matrix parentMatrix = mSharedElementParentMatrices.get(index);
            matrix.set(parentMatrix);
        }
    }

    protected ArrayList<SharedElementOriginalState> setSharedElementState(
            Bundle sharedElementState, final ArrayList<View> snapshots) {
        ArrayList<SharedElementOriginalState> originalImageState =
                new ArrayList<SharedElementOriginalState>();
        if (sharedElementState != null) {
            Matrix tempMatrix = new Matrix();
            RectF tempRect = new RectF();
            final int numSharedElements = mSharedElements.size();
            for (int i = 0; i < numSharedElements; i++) {
                View sharedElement = mSharedElements.get(i);
                String name = mSharedElementNames.get(i);
                SharedElementOriginalState originalState = getOldSharedElementState(sharedElement,
                        name, sharedElementState);
                originalImageState.add(originalState);
                setSharedElementState(sharedElement, name, sharedElementState,
                        tempMatrix, tempRect, null);
            }
        }
        if (mListener != null) {
            mListener.onSharedElementStart(mSharedElementNames, mSharedElements, snapshots);
        }
        return originalImageState;
    }

    protected void notifySharedElementEnd(ArrayList<View> snapshots) {
        if (mListener != null) {
            mListener.onSharedElementEnd(mSharedElementNames, mSharedElements, snapshots);
        }
    }

    protected void scheduleSetSharedElementEnd(final ArrayList<View> snapshots) {
        final View decorView = getDecor();
        if (decorView != null) {
            OneShotPreDrawListener.add(decorView, () -> {
                notifySharedElementEnd(snapshots);
            });
        }
    }

    private static SharedElementOriginalState getOldSharedElementState(View view, String name,
            Bundle transitionArgs) {

        SharedElementOriginalState state = new SharedElementOriginalState();
        state.mLeft = view.getLeft();
        state.mTop = view.getTop();
        state.mRight = view.getRight();
        state.mBottom = view.getBottom();
        state.mMeasuredWidth = view.getMeasuredWidth();
        state.mMeasuredHeight = view.getMeasuredHeight();
        state.mTranslationZ = view.getTranslationZ();
        state.mElevation = view.getElevation();
        if (!(view instanceof ImageView)) {
            return state;
        }
        Bundle bundle = transitionArgs.getBundle(name);
        if (bundle == null) {
            return state;
        }
        int scaleTypeInt = bundle.getInt(KEY_SCALE_TYPE, -1);
        if (scaleTypeInt < 0) {
            return state;
        }

        ImageView imageView = (ImageView) view;
        state.mScaleType = imageView.getScaleType();
        if (state.mScaleType == ImageView.ScaleType.MATRIX) {
            state.mMatrix = new Matrix(imageView.getImageMatrix());
        }
        return state;
    }

    protected ArrayList<View> createSnapshots(Bundle state, Collection<String> names) {
        int numSharedElements = names.size();
        ArrayList<View> snapshots = new ArrayList<View>(numSharedElements);
        if (numSharedElements == 0) {
            return snapshots;
        }
        Context context = getWindow().getContext();
        int[] decorLoc = new int[2];
        ViewGroup decorView = getDecor();
        if (decorView != null) {
            decorView.getLocationOnScreen(decorLoc);
        }
        Matrix tempMatrix = new Matrix();
        for (String name: names) {
            Bundle sharedElementBundle = state.getBundle(name);
            View snapshot = null;
            if (sharedElementBundle != null) {
                Parcelable parcelable = sharedElementBundle.getParcelable(KEY_SNAPSHOT);
                if (parcelable != null && mListener != null) {
                    snapshot = mListener.onCreateSnapshotView(context, parcelable);
                }
                if (snapshot != null) {
                    setSharedElementState(snapshot, name, state, tempMatrix, null, decorLoc);
                }
            }
            // Even null snapshots are added so they remain in the same order as shared elements.
            snapshots.add(snapshot);
        }
        return snapshots;
    }

    protected static void setOriginalSharedElementState(ArrayList<View> sharedElements,
            ArrayList<SharedElementOriginalState> originalState) {
        for (int i = 0; i < originalState.size(); i++) {
            View view = sharedElements.get(i);
            SharedElementOriginalState state = originalState.get(i);
            if (view instanceof ImageView && state.mScaleType != null) {
                ImageView imageView = (ImageView) view;
                imageView.setScaleType(state.mScaleType);
                if (state.mScaleType == ImageView.ScaleType.MATRIX) {
                  imageView.setImageMatrix(state.mMatrix);
                }
            }
            view.setElevation(state.mElevation);
            view.setTranslationZ(state.mTranslationZ);
            int widthSpec = View.MeasureSpec.makeMeasureSpec(state.mMeasuredWidth,
                    View.MeasureSpec.EXACTLY);
            int heightSpec = View.MeasureSpec.makeMeasureSpec(state.mMeasuredHeight,
                    View.MeasureSpec.EXACTLY);
            view.measure(widthSpec, heightSpec);
            view.layout(state.mLeft, state.mTop, state.mRight, state.mBottom);
        }
    }

    protected Bundle captureSharedElementState() {
        Bundle bundle = new Bundle();
        RectF tempBounds = new RectF();
        Matrix tempMatrix = new Matrix();
        for (int i = 0; i < mSharedElements.size(); i++) {
            View sharedElement = mSharedElements.get(i);
            String name = mSharedElementNames.get(i);
            captureSharedElementState(sharedElement, name, bundle, tempMatrix, tempBounds);
        }
        return bundle;
    }

    protected void clearState() {
        // Clear the state so that we can't hold any references accidentally and leak memory.
        mWindow = null;
        mSharedElements.clear();
        mTransitioningViews = null;
        mStrippedTransitioningViews = null;
        mOriginalAlphas.clear();
        mResultReceiver = null;
        mPendingTransition = null;
        mListener = null;
        mSharedElementParentMatrices = null;
    }

    protected long getFadeDuration() {
        return getWindow().getTransitionBackgroundFadeDuration();
    }

    protected void hideViews(ArrayList<View> views) {
        int count = views.size();
        for (int i = 0; i < count; i++) {
            View view = views.get(i);
            if (!mOriginalAlphas.containsKey(view)) {
                mOriginalAlphas.put(view, view.getAlpha());
            }
            view.setAlpha(0f);
        }
    }

    protected void showViews(ArrayList<View> views, boolean setTransitionAlpha) {
        int count = views.size();
        for (int i = 0; i < count; i++) {
            showView(views.get(i), setTransitionAlpha);
        }
    }

    private void showView(View view, boolean setTransitionAlpha) {
        Float alpha = mOriginalAlphas.remove(view);
        if (alpha != null) {
            view.setAlpha(alpha);
        }
        if (setTransitionAlpha) {
            view.setTransitionAlpha(1f);
        }
    }

    
Captures placement information for Views with a shared element name for
Activity Transitions.
Params:
view –           The View to capture the placement information for.
name –           The shared element name in the target Activity to apply the placement
                      information for.
transitionArgs – Bundle to store shared element placement information.
tempBounds –     A temporary Rect for capturing the current location of views./**
     * Captures placement information for Views with a shared element name for
     * Activity Transitions.
     *
     * @param view           The View to capture the placement information for.
     * @param name           The shared element name in the target Activity to apply the placement
     *                       information for.
     * @param transitionArgs Bundle to store shared element placement information.
     * @param tempBounds     A temporary Rect for capturing the current location of views.
     */
    protected void captureSharedElementState(View view, String name, Bundle transitionArgs,
            Matrix tempMatrix, RectF tempBounds) {
        Bundle sharedElementBundle = new Bundle();
        tempMatrix.reset();
        view.transformMatrixToGlobal(tempMatrix);
        tempBounds.set(0, 0, view.getWidth(), view.getHeight());
        tempMatrix.mapRect(tempBounds);

        sharedElementBundle.putFloat(KEY_SCREEN_LEFT, tempBounds.left);
        sharedElementBundle.putFloat(KEY_SCREEN_RIGHT, tempBounds.right);
        sharedElementBundle.putFloat(KEY_SCREEN_TOP, tempBounds.top);
        sharedElementBundle.putFloat(KEY_SCREEN_BOTTOM, tempBounds.bottom);
        sharedElementBundle.putFloat(KEY_TRANSLATION_Z, view.getTranslationZ());
        sharedElementBundle.putFloat(KEY_ELEVATION, view.getElevation());

        Parcelable bitmap = null;
        if (mListener != null) {
            bitmap = mListener.onCaptureSharedElementSnapshot(view, tempMatrix, tempBounds);
        }

        if (bitmap != null) {
            sharedElementBundle.putParcelable(KEY_SNAPSHOT, bitmap);
        }

        if (view instanceof ImageView) {
            ImageView imageView = (ImageView) view;
            int scaleTypeInt = scaleTypeToInt(imageView.getScaleType());
            sharedElementBundle.putInt(KEY_SCALE_TYPE, scaleTypeInt);
            if (imageView.getScaleType() == ImageView.ScaleType.MATRIX) {
                float[] matrix = new float[9];
                imageView.getImageMatrix().getValues(matrix);
                sharedElementBundle.putFloatArray(KEY_IMAGE_MATRIX, matrix);
            }
        }

        transitionArgs.putBundle(name, sharedElementBundle);
    }


    protected void startTransition(Runnable runnable) {
        if (mIsStartingTransition) {
            mPendingTransition = runnable;
        } else {
            mIsStartingTransition = true;
            runnable.run();
        }
    }

    protected void transitionStarted() {
        mIsStartingTransition = false;
    }

    
Cancels any pending transitions and returns true if there is a transition is in
the middle of starting.
/**
     * Cancels any pending transitions and returns true if there is a transition is in
     * the middle of starting.
     */
    protected boolean cancelPendingTransitions() {
        mPendingTransition = null;
        return mIsStartingTransition;
    }

    protected void moveSharedElementsToOverlay() {
        if (mWindow == null || !mWindow.getSharedElementsUseOverlay()) {
            return;
        }
        setSharedElementMatrices();
        int numSharedElements = mSharedElements.size();
        ViewGroup decor = getDecor();
        if (decor != null) {
            boolean moveWithParent = moveSharedElementWithParent();
            Matrix tempMatrix = new Matrix();
            for (int i = 0; i < numSharedElements; i++) {
                View view = mSharedElements.get(i);
                if (view.isAttachedToWindow()) {
                    tempMatrix.reset();
                    mSharedElementParentMatrices.get(i).invert(tempMatrix);
                    GhostView.addGhost(view, decor, tempMatrix);
                    ViewGroup parent = (ViewGroup) view.getParent();
                    if (moveWithParent && !isInTransitionGroup(parent, decor)) {
                        GhostViewListeners listener = new GhostViewListeners(view, parent, decor);
                        parent.getViewTreeObserver().addOnPreDrawListener(listener);
                        parent.addOnAttachStateChangeListener(listener);
                        mGhostViewListeners.add(listener);
                    }
                }
            }
        }
    }

    protected boolean moveSharedElementWithParent() {
        return true;
    }

    public static boolean isInTransitionGroup(ViewParent viewParent, ViewGroup decor) {
        if (viewParent == decor || !(viewParent instanceof ViewGroup)) {
            return false;
        }
        ViewGroup parent = (ViewGroup) viewParent;
        if (parent.isTransitionGroup()) {
            return true;
        } else {
            return isInTransitionGroup(parent.getParent(), decor);
        }
    }

    protected void moveSharedElementsFromOverlay() {
        int numListeners = mGhostViewListeners.size();
        for (int i = 0; i < numListeners; i++) {
            GhostViewListeners listener = mGhostViewListeners.get(i);
            listener.removeListener();
        }
        mGhostViewListeners.clear();

        if (mWindow == null || !mWindow.getSharedElementsUseOverlay()) {
            return;
        }
        ViewGroup decor = getDecor();
        if (decor != null) {
            ViewGroupOverlay overlay = decor.getOverlay();
            int count = mSharedElements.size();
            for (int i = 0; i < count; i++) {
                View sharedElement = mSharedElements.get(i);
                GhostView.removeGhost(sharedElement);
            }
        }
    }

    protected void setGhostVisibility(int visibility) {
        int numSharedElements = mSharedElements.size();
        for (int i = 0; i < numSharedElements; i++) {
            GhostView ghostView = GhostView.getGhost(mSharedElements.get(i));
            if (ghostView != null) {
                ghostView.setVisibility(visibility);
            }
        }
    }

    protected void scheduleGhostVisibilityChange(final int visibility) {
        final View decorView = getDecor();
        if (decorView != null) {
            OneShotPreDrawListener.add(decorView, () -> {
                setGhostVisibility(visibility);
            });
        }
    }

    protected boolean isViewsTransitionComplete() {
        return mViewsTransitionComplete;
    }

    protected void viewsTransitionComplete() {
        mViewsTransitionComplete = true;
        startInputWhenTransitionsComplete();
    }

    protected void backgroundAnimatorComplete() {
        mBackgroundAnimatorComplete = true;
    }

    protected void sharedElementTransitionComplete() {
        mSharedElementTransitionComplete = true;
        startInputWhenTransitionsComplete();
    }
    private void startInputWhenTransitionsComplete() {
        if (mViewsTransitionComplete && mSharedElementTransitionComplete) {
            final View decor = getDecor();
            if (decor != null) {
                final ViewRootImpl viewRoot = decor.getViewRootImpl();
                if (viewRoot != null) {
                    viewRoot.setPausedForTransition(false);
                }
            }
            onTransitionsComplete();
        }
    }

    protected void pauseInput() {
        final View decor = getDecor();
        final ViewRootImpl viewRoot = decor == null ? null : decor.getViewRootImpl();
        if (viewRoot != null) {
            viewRoot.setPausedForTransition(true);
        }
    }

    protected void onTransitionsComplete() {}

    protected class ContinueTransitionListener extends TransitionListenerAdapter {
        @Override
        public void onTransitionStart(Transition transition) {
            mIsStartingTransition = false;
            Runnable pending = mPendingTransition;
            mPendingTransition = null;
            if (pending != null) {
                startTransition(pending);
            }
        }

        @Override
        public void onTransitionEnd(Transition transition) {
            transition.removeListener(this);
        }
    }

    private static int scaleTypeToInt(ImageView.ScaleType scaleType) {
        for (int i = 0; i < SCALE_TYPE_VALUES.length; i++) {
            if (scaleType == SCALE_TYPE_VALUES[i]) {
                return i;
            }
        }
        return -1;
    }

    protected void setTransitioningViewsVisiblity(int visiblity, boolean invalidate) {
        final int numElements = mTransitioningViews == null ? 0 : mTransitioningViews.size();
        for (int i = 0; i < numElements; i++) {
            final View view = mTransitioningViews.get(i);
            if (invalidate) {
                // Allow the view to be invalidated by the visibility change
                view.setVisibility(visiblity);
            } else {
                // Don't invalidate the view with the visibility change
                view.setTransitionVisibility(visiblity);
            }
        }
    }

    
Blocks suppressLayout from Visibility transitions. It is ok to suppress the layout,
but we don't want to force the layout when suppressLayout becomes false. This leads
to visual glitches.
/**
     * Blocks suppressLayout from Visibility transitions. It is ok to suppress the layout,
     * but we don't want to force the layout when suppressLayout becomes false. This leads
     * to visual glitches.
     */
    private static void noLayoutSuppressionForVisibilityTransitions(Transition transition) {
        if (transition instanceof Visibility) {
            final Visibility visibility = (Visibility) transition;
            visibility.setSuppressLayout(false);
        } else if (transition instanceof TransitionSet) {
            final TransitionSet set = (TransitionSet) transition;
            final int count = set.getTransitionCount();
            for (int i = 0; i < count; i++) {
                noLayoutSuppressionForVisibilityTransitions(set.getTransitionAt(i));
            }
        }
    }

    public boolean isTransitionRunning() {
        return !(mViewsTransitionComplete && mSharedElementTransitionComplete &&
                mBackgroundAnimatorComplete);
    }

    private static class FixedEpicenterCallback extends Transition.EpicenterCallback {
        private Rect mEpicenter;

        public void setEpicenter(Rect epicenter) { mEpicenter = epicenter; }

        @Override
        public Rect onGetEpicenter(Transition transition) {
            return mEpicenter;
        }
    }

    private static class GhostViewListeners implements ViewTreeObserver.OnPreDrawListener,
            View.OnAttachStateChangeListener {
        private View mView;
        private ViewGroup mDecor;
        private View mParent;
        private Matrix mMatrix = new Matrix();
        private ViewTreeObserver mViewTreeObserver;

        public GhostViewListeners(View view, View parent, ViewGroup decor) {
            mView = view;
            mParent = parent;
            mDecor = decor;
            mViewTreeObserver = parent.getViewTreeObserver();
        }

        public View getView() {
            return mView;
        }

        @Override
        public boolean onPreDraw() {
            GhostView ghostView = GhostView.getGhost(mView);
            if (ghostView == null || !mView.isAttachedToWindow()) {
                removeListener();
            } else {
                GhostView.calculateMatrix(mView, mDecor, mMatrix);
                ghostView.setMatrix(mMatrix);
            }
            return true;
        }

        public void removeListener() {
            if (mViewTreeObserver.isAlive()) {
                mViewTreeObserver.removeOnPreDrawListener(this);
            } else {
                mParent.getViewTreeObserver().removeOnPreDrawListener(this);
            }
            mParent.removeOnAttachStateChangeListener(this);
        }

        @Override
        public void onViewAttachedToWindow(View v) {
            mViewTreeObserver = v.getViewTreeObserver();
        }

        @Override
        public void onViewDetachedFromWindow(View v) {
            removeListener();
        }
    }

    static class SharedElementOriginalState {
        int mLeft;
        int mTop;
        int mRight;
        int mBottom;
        int mMeasuredWidth;
        int mMeasuredHeight;
        ImageView.ScaleType mScaleType;
        Matrix mMatrix;
        float mTranslationZ;
        float mElevation;
    }
}