Ensure the intro view is always the top view in the draglayer if it is present

-> On devices post-api-16, we can achieve this just with child drawing order
   but on level 16 devices, child drawing order doesn't give us touch
   dispatch which is problematic for the intro screen.

issue 13796017

Change-Id: Ibf89ae91d8489f2de1eb9c8f235a0e6e6aed1847

1 files changed, 18 insertions, 5 deletions

diff --git a/src/com/android/launcher3/DragLayer.java b/src/com/android/launcher3/DragLayer.java
index cd51c96e1..c54db0127 100644
--- a/src/com/android/launcher3/DragLayer.java
+++ b/src/com/android/launcher3/DragLayer.java
@@ -122,10 +122,14 @@ public class DragLayer extends FrameLayout implements ViewGroup.OnHierarchyChang
         setInsets(child, mInsets, new Rect());
     }
 
-    public void showOverlayView(View introScreen) {
+    public void showOverlayView(View overlayView) {
         LayoutParams lp = new LayoutParams(LayoutParams.MATCH_PARENT, LayoutParams.MATCH_PARENT);
-        mOverlayView = introScreen;
-        addView(introScreen, lp);
+        mOverlayView = overlayView;
+        addView(overlayView, lp);
+
+        // ensure that the overlay view stays on top. we can't use drawing order for this
+        // because in API level 16 touch dispatch doesn't respect drawing order.
+        mOverlayView.bringToFront();
     }
 
     public void dismissOverlayView() {
@@ -774,6 +778,11 @@ public class DragLayer extends FrameLayout implements ViewGroup.OnHierarchyChang
 
     @Override
     public void onChildViewAdded(View parent, View child) {
+        if (mOverlayView != null) {
+            // ensure that the overlay view stays on top. we can't use drawing order for this
+            // because in API level 16 touch dispatch doesn't respect drawing order.
+            mOverlayView.bringToFront();
+        }
         updateChildIndices();
     }
 
@@ -785,6 +794,11 @@ public class DragLayer extends FrameLayout implements ViewGroup.OnHierarchyChang
     @Override
     public void bringChildToFront(View child) {
         super.bringChildToFront(child);
+        if (child != mOverlayView && mOverlayView != null) {
+            // ensure that the overlay view stays on top. we can't use drawing order for this
+            // because in API level 16 touch dispatch doesn't respect drawing order.
+            mOverlayView.bringToFront();
+        }
         updateChildIndices();
     }
 
@@ -792,8 +806,7 @@ public class DragLayer extends FrameLayout implements ViewGroup.OnHierarchyChang
         mTopViewIndex = -1;
         int childCount = getChildCount();
         for (int i = 0; i < childCount; i++) {
-            if (getChildAt(i) instanceof DragView ||
-                    getChildAt(i) == mOverlayView) {
+            if (getChildAt(i) instanceof DragView) {
                 mTopViewIndex = i;
             }
         }