Photo Picker: Implement animations for zoom switching

Bug: 1029056, 656015
Change-Id: Ib206c718ba4984d67209c708b4baa75e5f77816d
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1940186Reviewed-by: Boris Sazonov <bsazonov@chromium.org>
Commit-Queue: Finnur Thorarinsson <finnur@chromium.org>
Cr-Commit-Position: refs/heads/master@{#720203}

chrome/android/java/src/org/chromium/chrome/browser/photo_picker/PickerBitmapView.java

@@ -9,6 +9,7 @@ import android.animation.ObjectAnimator;
 import android.content.Context;
 import android.content.res.Resources;
 import android.graphics.Bitmap;
+import android.graphics.Color;
 import android.graphics.PorterDuff;
 import android.graphics.drawable.AnimationDrawable;
 import android.graphics.drawable.BitmapDrawable;
@@ -97,6 +98,10 @@ public class PickerBitmapView extends SelectableItemView<PickerBitmap> {
     // Whether the image has been loaded already.
     private boolean mImageLoaded;
 
+    // The background color to use for the tile (either the special tile or for pictures, when not
+    // animating).
+    private int mBackgroundColor = Color.TRANSPARENT;
+
     // The selected state of a given picture tile.
     private boolean mSelectedState;
 
@@ -188,6 +193,7 @@ public class PickerBitmapView extends SelectableItemView<PickerBitmap> {
     @Override
     protected boolean toggleSelectionForItem(PickerBitmap item) {
         if (isGalleryTile() || isCameraTile()) return false;
+        if (mCategoryView.isZoomSwitchingInEffect()) return false;
         return super.toggleSelectionForItem(item);
     }
 
@@ -458,7 +464,9 @@ public class PickerBitmapView extends SelectableItemView<PickerBitmap> {
             setEnabled(!anySelection);
         }
 
-        setBackgroundColor(ApiCompatibilityUtils.getColor(resources, bgColorId));
+        mBackgroundColor = ApiCompatibilityUtils.getColor(resources, bgColorId);
+        setBackgroundColor(mCategoryView.isZoomSwitchingInEffect() && !special ? Color.TRANSPARENT
+                                                                               : mBackgroundColor);
 
         // The visibility of the unselected toggle for multi-selection mode is a little more complex
         // because we don't want to show it when nothing is selected and also not on a blank canvas.

chrome/android/java/src/org/chromium/chrome/browser/photo_picker/PickerCategoryView.java

@@ -15,6 +15,9 @@ import android.net.Uri;
 import android.os.SystemClock;
 import android.support.v7.widget.GridLayoutManager;
 import android.support.v7.widget.RecyclerView;
+import android.transition.ChangeBounds;
+import android.transition.Transition;
+import android.transition.TransitionManager;
 import android.util.DisplayMetrics;
 import android.util.LruCache;
 import android.view.LayoutInflater;
@@ -44,6 +47,7 @@ import org.chromium.ui.UiUtils;
 
 import java.util.ArrayList;
 import java.util.Collections;
+import java.util.HashSet;
 import java.util.List;
 
 /**
@@ -410,6 +414,14 @@ public class PickerCategoryView extends RelativeLayout
     }
 
     private void flipZoomMode() {
+        // Bitmap scaling is cumulative, so if an image is selected when we switch modes, it will
+        // become skewed when switching between full size and square modes because dimensions of the
+        // picture also change (from square to full width). We therefore un-select all items before
+        // starting the animation and then reselect them once animation has ended.
+        final HashSet<PickerBitmap> selectedItems =
+                new HashSet<>(mSelectionDelegate.getSelectedItems());
+        mSelectionDelegate.clearSelection();
+
         mMagnifyingMode = !mMagnifyingMode;
 
         ImageView zoom = findViewById(R.id.zoom);
@@ -421,6 +433,33 @@ public class PickerCategoryView extends RelativeLayout
 
         calculateGridMetrics();
 
+        mZoomSwitchingInEffect = true;
+
+        ChangeBounds transition = new ChangeBounds();
+        transition.addListener(new Transition.TransitionListener() {
+            @Override
+            public void onTransitionStart(Transition transition) {}
+
+            @Override
+            public void onTransitionEnd(Transition transition) {
+                mZoomSwitchingInEffect = false;
+
+                // Redo selection when switching between modes to make it obvious what got selected.
+                mSelectionDelegate.setSelectedItems(selectedItems);
+            }
+
+            @Override
+            public void onTransitionCancel(Transition transition) {}
+
+            @Override
+            public void onTransitionPause(Transition transition) {}
+
+            @Override
+            public void onTransitionResume(Transition transition) {}
+        });
+
+        TransitionManager.beginDelayedTransition(mRecyclerView, transition);
+
         mLayoutManager.setSpanCount(mColumns);
         mPickerAdapter.notifyDataSetChanged();
         mRecyclerView.requestLayout();
@@ -444,6 +483,10 @@ public class PickerCategoryView extends RelativeLayout
         return mMagnifyingMode;
     }
 
+    public boolean isZoomSwitchingInEffect() {
+        return mZoomSwitchingInEffect;
+    }
+
     public SelectionDelegate<PickerBitmap> getSelectionDelegate() {
         return mSelectionDelegate;
     }