Add DashboardItemAnimator to stop flash

When there is no offset change for identical holder in
animateChange, simply return and don't invoke the
resetAnimation.

Bug: 33198024
Test: make RunSettingsRoboTests
Change-Id: Ib83363873bc5f51e5bd71af5a013ee0756728d1a

src/com/android/settings/dashboard/DashboardItemAnimator.java

@@ -0,0 +1,37 @@
+/*
+ * Copyright (C) 2016 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.android.settings.dashboard;
+
+import android.support.v4.view.ViewCompat;
+import android.support.v7.widget.DefaultItemAnimator;
+import android.support.v7.widget.RecyclerView.ViewHolder;
+
+public class DashboardItemAnimator extends DefaultItemAnimator {
+
+    @Override
+    public boolean animateChange(ViewHolder oldHolder, ViewHolder newHolder, int fromX, int fromY,
+            int toX, int toY) {
+        if (oldHolder == newHolder) {
+            fromX += ViewCompat.getTranslationX(oldHolder.itemView);
+            fromY += ViewCompat.getTranslationY(oldHolder.itemView);
+            if (fromX == toX && fromY == toY) {
+                dispatchMoveFinished(oldHolder);
+                return false;
+            }
+        }
+        return super.animateChange(oldHolder, newHolder, fromX, fromY, toX, toY);
+    }
+}