Correctly invalidate views that transition from opaque to non-opaque.

Bug #3337037

Change-Id: I31397273a31b6004e2e3801866122bcbb3ebee5d

2 files changed, 11 insertions, 4 deletions

diff --git a/core/java/android/view/View.java b/core/java/android/view/View.java
index 811a633..c4bfe6c 100644
--- a/core/java/android/view/View.java
+++ b/core/java/android/view/View.java
@@ -1813,6 +1813,8 @@ public class View implements Drawable.Callback, KeyEvent.Callback, Accessibility
     private int mPrevWidth = -1;
     private int mPrevHeight = -1;
 
+    private boolean mLastIsOpaque;    
+    
     /**
      * Convenience value to check for float values that are close enough to zero to be considered
      * zero.
@@ -6717,7 +6719,7 @@ public class View implements Drawable.Callback, KeyEvent.Callback, Accessibility
     public void invalidate() {
         invalidate(true);
     }
-
+    
     /**
      * This is where the invalidate() work actually happens. A full invalidate()
      * causes the drawing cache to be invalidated, but this function can be called with
@@ -6734,8 +6736,11 @@ public class View implements Drawable.Callback, KeyEvent.Callback, Accessibility
             ViewDebug.trace(this, ViewDebug.HierarchyTraceType.INVALIDATE);
         }
 
+        boolean opaque = isOpaque();
         if ((mPrivateFlags & (DRAWN | HAS_BOUNDS)) == (DRAWN | HAS_BOUNDS) ||
-                (invalidateCache && (mPrivateFlags & DRAWING_CACHE_VALID) == DRAWING_CACHE_VALID)) {
+                (invalidateCache && (mPrivateFlags & DRAWING_CACHE_VALID) == DRAWING_CACHE_VALID) ||
+                opaque != mLastIsOpaque) {
+            mLastIsOpaque = opaque;
             mPrivateFlags &= ~DRAWN;
             if (invalidateCache) {
                 mPrivateFlags &= ~DRAWING_CACHE_VALID;
diff --git a/core/java/android/view/ViewRoot.java b/core/java/android/view/ViewRoot.java
index 2c6ec71..ad101f8 100644
--- a/core/java/android/view/ViewRoot.java
+++ b/core/java/android/view/ViewRoot.java
@@ -710,8 +710,10 @@ public final class ViewRoot extends Handler implements ViewParent,
             // object is not initialized to its backing store, but soon it
             // will be (assuming the window is visible).
             attachInfo.mSurface = mSurface;
-            attachInfo.mUse32BitDrawingCache = PixelFormat.formatHasAlpha(lp.format) ||
-                    lp.format == PixelFormat.RGBX_8888;
+            // We used to use the following condition to choose 32 bits drawing caches:
+            // PixelFormat.hasAlpha(lp.format) || lp.format == PixelFormat.RGBX_8888
+            // However, windows are now always 32 bits by default, so choose 32 bits
+            attachInfo.mUse32BitDrawingCache = true;
             attachInfo.mHasWindowFocus = false;
             attachInfo.mWindowVisibility = viewVisibility;
             attachInfo.mRecomputeGlobalAttributes = false;