Add workaround to prevent ViewPager from crashing

Bug: 11721001
Change-Id: I0824f82c30a288a3c1f0ea69e07f10bdeb744bbc

java/res/layout/emoji_palettes_view.xml

@@ -73,7 +73,7 @@
             android:background="@color/emoji_key_background_color"
             android:src="@drawable/sym_keyboard_delete_holo_dark" />
     </LinearLayout>
-    <android.support.v4.view.ViewPager
+    <com.android.inputmethod.keyboard.internal.CustomViewPager
         android:id="@+id/emoji_keyboard_pager"
         android:layout_width="match_parent"
         android:layout_height="wrap_content" />

java/src/com/android/inputmethod/keyboard/internal/CustomViewPager.java

@@ -0,0 +1,47 @@
+/*
+ * Copyright (C) 2013 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.inputmethod.keyboard.internal;
+
+import android.content.Context;
+import android.support.v4.view.ViewPager;
+import android.util.AttributeSet;
+import android.util.Log;
+import android.view.MotionEvent;
+
+/**
+ * Custom view pager to prevent {@link ViewPager} from crashing while handling multi-touch
+ * event.
+ */
+public class CustomViewPager extends ViewPager {
+    private static final String TAG = CustomViewPager.class.getSimpleName();
+
+    public CustomViewPager(final Context context, final AttributeSet attrs) {
+        super(context, attrs);
+    }
+
+    @Override
+    public boolean onInterceptTouchEvent(final MotionEvent event) {
+        // This only happens when you multi-touch, take the first finger off and move.
+        // Unfortunately this causes {@link ViewPager} to crash, so we will ignore such events.
+        if (event.getAction() == MotionEvent.ACTION_MOVE && event.getPointerId(0) != 0) {
+            Log.w(TAG, "Ignored multi-touch move event to prevent ViewPager from crashing");
+            return false;
+        }
+
+        return super.onInterceptTouchEvent(event);
+    }
+}