https://source.android.com/ 
/*
 * Copyright (C) 2013 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.transition;

import android.animation.Animator;
import android.animation.AnimatorListenerAdapter;
import android.animation.AnimatorSet;
import android.animation.ObjectAnimator;
import android.animation.RectEvaluator;
import android.animation.ValueAnimator;
import android.graphics.Bitmap;
import android.graphics.Canvas;
import android.graphics.Rect;
import android.graphics.drawable.BitmapDrawable;
import android.util.Log;
import android.view.SurfaceView;
import android.view.TextureView;
import android.view.View;
import android.view.ViewGroup;
import android.view.ViewOverlay;

import java.util.Map;


This transition captures bitmap representations of target views before and
after the scene change and fades between them.

Note: This transition is not compatible with TextureView or SurfaceView.


@hide
/**
 * This transition captures bitmap representations of target views before and
 * after the scene change and fades between them.
 *
 * <p>Note: This transition is not compatible with {@link TextureView}
 * or {@link SurfaceView}.</p>
 *
 * @hide
 */
public class Crossfade extends Transition {
    // TODO: Add a hook that lets a Transition call user code to query whether it should run on
    // a given target view. This would save bitmap comparisons in this transition, for example.

    private static final String LOG_TAG = "Crossfade";

    private static final String PROPNAME_BITMAP = "android:crossfade:bitmap";
    private static final String PROPNAME_DRAWABLE = "android:crossfade:drawable";
    private static final String PROPNAME_BOUNDS = "android:crossfade:bounds";

    private static RectEvaluator sRectEvaluator = new RectEvaluator();

    private int mFadeBehavior = FADE_BEHAVIOR_REVEAL;
    private int mResizeBehavior = RESIZE_BEHAVIOR_SCALE;

    
Flag specifying that the fading animation should cross-fade
between the old and new representation of all affected target
views. This means that the old representation will fade out
while the new one fades in. This effect may work well on views
without solid backgrounds, such as TextViews.

See Also:
  • setFadeBehavior(int)
/**
     * Flag specifying that the fading animation should cross-fade
     * between the old and new representation of all affected target
     * views. This means that the old representation will fade out
     * while the new one fades in. This effect may work well on views
     * without solid backgrounds, such as TextViews.
     *
     * @see #setFadeBehavior(int)
     */
    public static final int FADE_BEHAVIOR_CROSSFADE = 0;
    
Flag specifying that the fading animation should reveal the
new representation of all affected target views. This means
that the old representation will fade out, gradually
revealing the new representation, which remains opaque
the whole time. This effect may work well on views
with solid backgrounds, such as ImageViews.

See Also:
  • setFadeBehavior(int)
/**
     * Flag specifying that the fading animation should reveal the
     * new representation of all affected target views. This means
     * that the old representation will fade out, gradually
     * revealing the new representation, which remains opaque
     * the whole time. This effect may work well on views
     * with solid backgrounds, such as ImageViews.
     *
     * @see #setFadeBehavior(int)
     */
    public static final int FADE_BEHAVIOR_REVEAL = 1;
    
Flag specifying that the fading animation should first fade
out the original representation completely and then fade in the
new one. This effect may be more suitable than the other
fade behaviors for views with.

See Also:
  • setFadeBehavior(int)
/**
     * Flag specifying that the fading animation should first fade
     * out the original representation completely and then fade in the
     * new one. This effect may be more suitable than the other
     * fade behaviors for views with.
     *
     * @see #setFadeBehavior(int)
     */
    public static final int FADE_BEHAVIOR_OUT_IN = 2;

    
Flag specifying that the transition should not animate any
changes in size between the old and new target views.
This means that no scaling will take place as a result of
this transition

See Also:
  • setResizeBehavior(int)
/**
     * Flag specifying that the transition should not animate any
     * changes in size between the old and new target views.
     * This means that no scaling will take place as a result of
     * this transition
     *
     * @see #setResizeBehavior(int)
     */
    public static final int RESIZE_BEHAVIOR_NONE = 0;
    
Flag specifying that the transition should animate any
changes in size between the old and new target views.
This means that the animation will scale the start/end
representations of affected views from the starting size
to the ending size over the course of the animation.
This effect may work well on images, but is not recommended
for text.

See Also:
  • setResizeBehavior(int)
/**
     * Flag specifying that the transition should animate any
     * changes in size between the old and new target views.
     * This means that the animation will scale the start/end
     * representations of affected views from the starting size
     * to the ending size over the course of the animation.
     * This effect may work well on images, but is not recommended
     * for text.
     *
     * @see #setResizeBehavior(int)
     */
    public static final int RESIZE_BEHAVIOR_SCALE = 1;

    // TODO: Add fade/resize behaviors to xml resources

    
Sets the type of fading animation that will be run, one of FADE_BEHAVIOR_CROSSFADE and FADE_BEHAVIOR_REVEAL. 
Params:
  • fadeBehavior – The type of fading animation to use when this
transition is run.
/**
     * Sets the type of fading animation that will be run, one of
     * {@link #FADE_BEHAVIOR_CROSSFADE} and {@link #FADE_BEHAVIOR_REVEAL}.
     *
     * @param fadeBehavior The type of fading animation to use when this
     * transition is run.
     */
    public Crossfade setFadeBehavior(int fadeBehavior) {
        if (fadeBehavior >= FADE_BEHAVIOR_CROSSFADE && fadeBehavior <= FADE_BEHAVIOR_OUT_IN) {
            mFadeBehavior = fadeBehavior;
        }
        return this;
    }

    
Returns the fading behavior of the animation.

See Also:
Returns:This crossfade object.
/**
     * Returns the fading behavior of the animation.
     *
     * @return This crossfade object.
     * @see #setFadeBehavior(int)
     */
    public int getFadeBehavior() {
        return mFadeBehavior;
    }

    
Sets the type of resizing behavior that will be used during the transition animation, one of RESIZE_BEHAVIOR_NONE and RESIZE_BEHAVIOR_SCALE. 
Params:
  • resizeBehavior – The type of resizing behavior to use when this
transition is run.
/**
     * Sets the type of resizing behavior that will be used during the
     * transition animation, one of {@link #RESIZE_BEHAVIOR_NONE} and
     * {@link #RESIZE_BEHAVIOR_SCALE}.
     *
     * @param resizeBehavior The type of resizing behavior to use when this
     * transition is run.
     */
    public Crossfade setResizeBehavior(int resizeBehavior) {
        if (resizeBehavior >= RESIZE_BEHAVIOR_NONE && resizeBehavior <= RESIZE_BEHAVIOR_SCALE) {
            mResizeBehavior = resizeBehavior;
        }
        return this;
    }

    
Returns the resizing behavior of the animation.

See Also:
Returns:This crossfade object.
/**
     * Returns the resizing behavior of the animation.
     *
     * @return This crossfade object.
     * @see #setResizeBehavior(int)
     */
    public int getResizeBehavior() {
        return mResizeBehavior;
    }

    @Override
    public Animator createAnimator(ViewGroup sceneRoot, TransitionValues startValues,
            TransitionValues endValues) {
        if (startValues == null || endValues == null) {
            return null;
        }
        final boolean useParentOverlay = mFadeBehavior != FADE_BEHAVIOR_REVEAL;
        final View view = endValues.view;
        Map<String, Object> startVals = startValues.values;
        Map<String, Object> endVals = endValues.values;
        Rect startBounds = (Rect) startVals.get(PROPNAME_BOUNDS);
        Rect endBounds = (Rect) endVals.get(PROPNAME_BOUNDS);
        Bitmap startBitmap = (Bitmap) startVals.get(PROPNAME_BITMAP);
        Bitmap endBitmap = (Bitmap) endVals.get(PROPNAME_BITMAP);
        final BitmapDrawable startDrawable = (BitmapDrawable) startVals.get(PROPNAME_DRAWABLE);
        final BitmapDrawable endDrawable = (BitmapDrawable) endVals.get(PROPNAME_DRAWABLE);
        if (Transition.DBG) {
            Log.d(LOG_TAG, "StartBitmap.sameAs(endBitmap) = " + startBitmap.sameAs(endBitmap) +
                    " for start, end: " + startBitmap + ", " + endBitmap);
        }
        if (startDrawable != null && endDrawable != null && !startBitmap.sameAs(endBitmap)) {
            ViewOverlay overlay = useParentOverlay ?
                    ((ViewGroup) view.getParent()).getOverlay() : view.getOverlay();
            if (mFadeBehavior == FADE_BEHAVIOR_REVEAL) {
                overlay.add(endDrawable);
            }
            overlay.add(startDrawable);
            // The transition works by placing the end drawable under the start drawable and
            // gradually fading out the start drawable. So it's not really a cross-fade, but rather
            // a reveal of the end scene over time. Also, animate the bounds of both drawables
            // to mimic the change in the size of the view itself between scenes.
            ObjectAnimator anim;
            if (mFadeBehavior == FADE_BEHAVIOR_OUT_IN) {
                // Fade out completely halfway through the transition
                anim = ObjectAnimator.ofInt(startDrawable, "alpha", 255, 0, 0);
            } else {
                anim = ObjectAnimator.ofInt(startDrawable, "alpha", 0);
            }
            anim.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
                @Override
                public void onAnimationUpdate(ValueAnimator animation) {
                    // TODO: some way to auto-invalidate views based on drawable changes? callbacks?
                    view.invalidate(startDrawable.getBounds());
                }
            });
            ObjectAnimator anim1 = null;
            if (mFadeBehavior == FADE_BEHAVIOR_OUT_IN) {
                // start fading in halfway through the transition
                anim1 = ObjectAnimator.ofFloat(view, View.ALPHA, 0, 0, 1);
            } else if (mFadeBehavior == FADE_BEHAVIOR_CROSSFADE) {
                anim1 = ObjectAnimator.ofFloat(view, View.ALPHA, 0, 1);
            }
            if (Transition.DBG) {
                Log.d(LOG_TAG, "Crossfade: created anim " + anim + " for start, end values " +
                        startValues + ", " + endValues);
            }
            anim.addListener(new AnimatorListenerAdapter() {
                @Override
                public void onAnimationEnd(Animator animation) {
                    ViewOverlay overlay = useParentOverlay ?
                            ((ViewGroup) view.getParent()).getOverlay() : view.getOverlay();
                    overlay.remove(startDrawable);
                    if (mFadeBehavior == FADE_BEHAVIOR_REVEAL) {
                        overlay.remove(endDrawable);
                    }
                }
            });
            AnimatorSet set = new AnimatorSet();
            set.playTogether(anim);
            if (anim1 != null) {
                set.playTogether(anim1);
            }
            if (mResizeBehavior == RESIZE_BEHAVIOR_SCALE && !startBounds.equals(endBounds)) {
                if (Transition.DBG) {
                    Log.d(LOG_TAG, "animating from startBounds to endBounds: " +
                            startBounds + ", " + endBounds);
                }
                Animator anim2 = ObjectAnimator.ofObject(startDrawable, "bounds",
                        sRectEvaluator, startBounds, endBounds);
                set.playTogether(anim2);
                if (mResizeBehavior == RESIZE_BEHAVIOR_SCALE) {
                    // TODO: How to handle resizing with a CROSSFADE (vs. REVEAL) effect
                    // when we are animating the view directly?
                    Animator anim3 = ObjectAnimator.ofObject(endDrawable, "bounds",
                            sRectEvaluator, startBounds, endBounds);
                    set.playTogether(anim3);
                }
            }
            return set;
        } else {
            return null;
        }
    }

    private void captureValues(TransitionValues transitionValues) {
        View view = transitionValues.view;
        Rect bounds = new Rect(0, 0, view.getWidth(), view.getHeight());
        if (mFadeBehavior != FADE_BEHAVIOR_REVEAL) {
            bounds.offset(view.getLeft(), view.getTop());
        }
        transitionValues.values.put(PROPNAME_BOUNDS, bounds);

        if (Transition.DBG) {
            Log.d(LOG_TAG, "Captured bounds " + transitionValues.values.get(PROPNAME_BOUNDS));
        }
        Bitmap bitmap = Bitmap.createBitmap(view.getWidth(), view.getHeight(),
                Bitmap.Config.ARGB_8888);
        if (view instanceof TextureView) {
            bitmap = ((TextureView) view).getBitmap();
        } else {
            Canvas c = new Canvas(bitmap);
            view.draw(c);
        }
        transitionValues.values.put(PROPNAME_BITMAP, bitmap);
        // TODO: I don't have resources, can't call the non-deprecated method?
        BitmapDrawable drawable = new BitmapDrawable(bitmap);
        // TODO: lrtb will be wrong if the view has transXY set
        drawable.setBounds(bounds);
        transitionValues.values.put(PROPNAME_DRAWABLE, drawable);
    }

    @Override
    public void captureStartValues(TransitionValues transitionValues) {
        captureValues(transitionValues);
    }

    @Override
    public void captureEndValues(TransitionValues transitionValues) {
        captureValues(transitionValues);
    }
}