Adding in-activity intro screen (issue 12905636)

Change-Id: Ifb016ca6e5052fd91535b98a39f78569200955a8

1 files changed, 32 insertions, 10 deletions

diff --git a/src/com/android/launcher3/DragLayer.java b/src/com/android/launcher3/DragLayer.java
index 862ceca28..7ccbe6b55 100644
--- a/src/com/android/launcher3/DragLayer.java
+++ b/src/com/android/launcher3/DragLayer.java
@@ -73,7 +73,8 @@ public class DragLayer extends FrameLayout implements ViewGroup.OnHierarchyChang
 
     private final Rect mInsets = new Rect();
 
-    private int mDragViewIndex;
+    private View mOverlayView;
+    private int mTopViewIndex;
 
     /**
      * Used to create a new DragLayer from XML.
@@ -120,6 +121,16 @@ public class DragLayer extends FrameLayout implements ViewGroup.OnHierarchyChang
         setInsets(child, mInsets, new Rect());
     }
 
+    public void showOverlayView(View introScreen) {
+        LayoutParams lp = new LayoutParams(LayoutParams.MATCH_PARENT, LayoutParams.MATCH_PARENT);
+        mOverlayView = introScreen;
+        addView(introScreen, lp);
+    }
+
+    public void dismissOverlayView() {
+        removeView(mOverlayView);
+    }
+
     private void setInsets(View child, Rect newInsets, Rect oldInsets) {
         final FrameLayout.LayoutParams flp = (FrameLayout.LayoutParams) child.getLayoutParams();
         if (child instanceof Insettable) {
@@ -770,27 +781,38 @@ public class DragLayer extends FrameLayout implements ViewGroup.OnHierarchyChang
         updateChildIndices();
     }
 
+    @Override
+    public void bringChildToFront(View child) {
+        super.bringChildToFront(child);
+        updateChildIndices();
+    }
+
     private void updateChildIndices() {
-        mDragViewIndex = -1;
+        mTopViewIndex = -1;
         int childCount = getChildCount();
         for (int i = 0; i < childCount; i++) {
-            if (getChildAt(i) instanceof DragView) {
-                mDragViewIndex = i;
+            if (getChildAt(i) instanceof DragView ||
+                    getChildAt(i) == mOverlayView) {
+                mTopViewIndex = i;
             }
         }
     }
 
     @Override
     protected int getChildDrawingOrder(int childCount, int i) {
-        if (mDragViewIndex == -1) {
+        // i represents the current draw iteration
+        if (mTopViewIndex == -1) {
+            // in general we do nothing
             return i;
-        } else if (i == mDragViewIndex) {
-            return getChildCount()-1;
-        } else if (i < mDragViewIndex) {
+        } else if (i == childCount - 1) {
+            // if we have a top index, we return it when drawing last item (highest z-order)
+            return mTopViewIndex;
+        } else if (i < mTopViewIndex) {
             return i;
         } else {
-            // i > mDragViewIndex
-            return i-1;
+            // for indexes greater than the top index, we fetch one item above to shift for the
+            // displacement of the top index
+            return i + 1;
         }
     }