* Shows a vertical "explode" animation for any view inside a view group (e.g. views inside a * ListView). During the animation, a snapshot is taken for the view to the animated and * presented in a popup window or view overlay on top of the original view group. The background * of the view (a highlight) vertically expands (explodes) during the animation. *
** The exact implementation of the animation depends on platform API level. For JB_MR2 and later, * the implementation utilizes ViewOverlay to perform highly performant overlay animations; for * older API levels, the implementation falls back to using a full screen popup window to stage * the animation. *
** To start this animation, call {@link #startAnimationForView(ViewGroup, View, View, boolean, int)} *
*/ public class ViewGroupItemVerticalExplodeAnimation { /** * Starts a vertical explode animation for a given view situated in a given container. * * @param container the container of the view which determines the explode animation's final * size * @param viewToAnimate the view to be animated. The view will be highlighted by the explode * highlight, which expands from the size of the view to the size of the container. * @param animationStagingView the view that stages the animation. Since viewToAnimate may be * removed from the view tree during the animation, we need a view that'll be alive * for the duration of the animation so that the animation won't get cancelled. * @param snapshotView whether a snapshot of the view to animate is needed. */ public static void startAnimationForView(final ViewGroup container, final View viewToAnimate, final View animationStagingView, final boolean snapshotView, final int duration) { if (OsUtil.isAtLeastJB_MR2() && (viewToAnimate.getContext() instanceof Activity)) { new ViewExplodeAnimationJellyBeanMR2(viewToAnimate, container, snapshotView, duration) .startAnimation(); } else { // Pre JB_MR2, this animation can cause rendering failures which causes the framework // to fall back to software rendering where camera preview isn't supported (b/18264647) // just skip the animation to avoid this case. } } /** * Implementation class for API level >= 18. */ @TargetApi(18) private static class ViewExplodeAnimationJellyBeanMR2 { private final View mViewToAnimate; private final ViewGroup mContainer; private final View mSnapshot; private final Bitmap mViewBitmap; private final int mDuration; public ViewExplodeAnimationJellyBeanMR2(final View viewToAnimate, final ViewGroup container, final boolean snapshotView, final int duration) { mViewToAnimate = viewToAnimate; mContainer = container; mDuration = duration; if (snapshotView) { mViewBitmap = snapshotView(viewToAnimate); mSnapshot = new View(viewToAnimate.getContext()); } else { mSnapshot = null; mViewBitmap = null; } } public void startAnimation() { final Context context = mViewToAnimate.getContext(); final Resources resources = context.getResources(); final View decorView = ((Activity) context).getWindow().getDecorView(); final ViewOverlay viewOverlay = decorView.getOverlay(); if (viewOverlay instanceof ViewGroupOverlay) { final ViewGroupOverlay overlay = (ViewGroupOverlay) viewOverlay; // Add a shadow layer to the overlay. final FrameLayout shadowContainerLayer = new FrameLayout(context); final Drawable oldBackground = mViewToAnimate.getBackground(); final Rect containerRect = UiUtils.getMeasuredBoundsOnScreen(mContainer); final Rect decorRect = UiUtils.getMeasuredBoundsOnScreen(decorView); // Position the container rect relative to the decor rect since the decor rect // defines whether the view overlay will be positioned. containerRect.offset(-decorRect.left, -decorRect.top); shadowContainerLayer.setLeft(containerRect.left); shadowContainerLayer.setTop(containerRect.top); shadowContainerLayer.setBottom(containerRect.bottom); shadowContainerLayer.setRight(containerRect.right); shadowContainerLayer.setBackgroundColor(resources.getColor( R.color.open_conversation_animation_background_shadow)); // Per design request, temporarily clear out the background of the item content // to not show any ripple effects during animation. if (!(oldBackground instanceof ColorDrawable)) { mViewToAnimate.setBackground(null); } overlay.add(shadowContainerLayer); // Add a expand layer and position it with in the shadow background, so it can // be properly clipped to the container bounds during the animation. final View expandLayer = new View(context); final int elevation = resources.getDimensionPixelSize( R.dimen.explode_animation_highlight_elevation); final Rect viewRect = UiUtils.getMeasuredBoundsOnScreen(mViewToAnimate); // Frame viewRect from screen space to containerRect space. viewRect.offset(-containerRect.left - decorRect.left, -containerRect.top - decorRect.top); // Since the expand layer expands at the same rate above and below, we need to // compute the expand scale using the bigger of the top/bottom distances. final int expandLayerHalfHeight = viewRect.height() / 2; final int topDist = viewRect.top; final int bottomDist = containerRect.height() - viewRect.bottom; final float scale = expandLayerHalfHeight == 0 ? 1 : ((float) Math.max(topDist, bottomDist) + expandLayerHalfHeight) / expandLayerHalfHeight; // Position the expand layer initially to exactly match the animated item. shadowContainerLayer.addView(expandLayer); expandLayer.setLeft(viewRect.left); expandLayer.setTop(viewRect.top); expandLayer.setBottom(viewRect.bottom); expandLayer.setRight(viewRect.right); expandLayer.setBackgroundColor(resources.getColor( R.color.conversation_background)); ViewCompat.setElevation(expandLayer, elevation); // Conditionally stage the snapshot in the overlay. if (mSnapshot != null) { shadowContainerLayer.addView(mSnapshot); mSnapshot.setLeft(viewRect.left); mSnapshot.setTop(viewRect.top); mSnapshot.setBottom(viewRect.bottom); mSnapshot.setRight(viewRect.right); mSnapshot.setBackground(new BitmapDrawable(resources, mViewBitmap)); ViewCompat.setElevation(mSnapshot, elevation); } // Apply a scale animation to scale to full screen. expandLayer.animate().scaleY(scale) .setDuration(mDuration) .setInterpolator(UiUtils.EASE_IN_INTERPOLATOR) .withEndAction(new Runnable() { @Override public void run() { // Clean up the views added to overlay on animation finish. overlay.remove(shadowContainerLayer); mViewToAnimate.setBackground(oldBackground); if (mViewBitmap != null) { mViewBitmap.recycle(); } } }); } } } /** * Take a snapshot of the given review, return a Bitmap object that's owned by the caller. */ static Bitmap snapshotView(final View view) { // Save the content of the view into a bitmap. final Bitmap viewBitmap = Bitmap.createBitmap(view.getWidth(), view.getHeight(), Bitmap.Config.ARGB_8888); // Strip the view of its background when taking a snapshot so that things like touch // feedback don't get accidentally snapshotted. final Drawable viewBackground = view.getBackground(); ImageUtils.setBackgroundDrawableOnView(view, null); view.draw(new Canvas(viewBitmap)); ImageUtils.setBackgroundDrawableOnView(view, viewBackground); return viewBitmap; } }