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      1 /*
      2  * Copyright (C) 2012 The Android Open Source Project
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *      http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 
     17 package com.android.contacts.util;
     18 
     19 import android.view.View;
     20 import android.view.ViewTreeObserver.OnDrawListener;
     21 import android.view.ViewTreeObserver.OnGlobalLayoutListener;
     22 import android.view.ViewTreeObserver.OnPreDrawListener;
     23 
     24 /** Static methods that are useful for scheduling actions to occur at a later time. */
     25 public class SchedulingUtils {
     26 
     27 
     28     /** Runs a piece of code after the next layout run */
     29     public static void doAfterLayout(final View view, final Runnable runnable) {
     30         final OnGlobalLayoutListener listener = new OnGlobalLayoutListener() {
     31             @Override
     32             public void onGlobalLayout() {
     33                 // Layout pass done, unregister for further events
     34                 view.getViewTreeObserver().removeOnGlobalLayoutListener(this);
     35                 runnable.run();
     36             }
     37         };
     38         view.getViewTreeObserver().addOnGlobalLayoutListener(listener);
     39     }
     40 
     41     /** Runs a piece of code just before the next draw, after layout and measurement */
     42     public static void doOnPreDraw(final View view, final boolean drawNextFrame,
     43             final Runnable runnable) {
     44         final OnPreDrawListener listener = new OnPreDrawListener() {
     45             @Override
     46             public boolean onPreDraw() {
     47                 view.getViewTreeObserver().removeOnPreDrawListener(this);
     48                 runnable.run();
     49                 return drawNextFrame;
     50             }
     51         };
     52         view.getViewTreeObserver().addOnPreDrawListener(listener);
     53     }
     54 }
     55