Merge "Animate the action bar's Up chevron as it shows and hides." into jb-mr1-dev

Author: adamp

core/java/com/android/internal/widget/ActionBarView.java

@@ -26,6 +26,7 @@
 import com.android.internal.view.menu.MenuView;
 import com.android.internal.view.menu.SubMenuBuilder;
 
+import android.animation.LayoutTransition;
 import android.app.ActionBar;
 import android.app.ActionBar.OnNavigationListener;
 import android.app.Activity;
@@ -1271,12 +1272,19 @@ private static class HomeView extends FrameLayout {
         private ImageView mIconView;
         private int mUpWidth;
 
+        private static final long DEFAULT_TRANSITION_DURATION = 150;
+
         public HomeView(Context context) {
             this(context, null);
         }
 
         public HomeView(Context context, AttributeSet attrs) {
             super(context, attrs);
+            LayoutTransition t = getLayoutTransition();
+            if (t != null) {
+                // Set a lower duration than the default
+                t.setDuration(DEFAULT_TRANSITION_DURATION);
+            }
         }
 
         public void setUp(boolean isUp) {

core/res/res/layout/action_bar_home.xml

@@ -18,7 +18,8 @@
       class="com.android.internal.widget.ActionBarView$HomeView"
       android:layout_width="wrap_content"
       android:layout_height="match_parent"
-      android:background="?android:attr/actionBarItemBackground" >
+      android:background="?android:attr/actionBarItemBackground"
+      android:animateLayoutChanges="true">
     <ImageView android:id="@android:id/up"
                android:src="?android:attr/homeAsUpIndicator"
                android:layout_gravity="center_vertical|start"