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      1 /*
      2  * Copyright (C) 2015 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.systemui;
     18 
     19 import android.os.Handler;
     20 import android.os.Looper;
     21 import android.view.Choreographer;
     22 
     23 import java.util.ArrayList;
     24 
     25 /**
     26  * Utility class for methods used to dejank the UI.
     27  */
     28 public class DejankUtils {
     29 
     30     private static final Choreographer sChoreographer = Choreographer.getInstance();
     31     private static final Handler sHandler = new Handler();
     32 
     33     private static final ArrayList<Runnable> sPendingRunnables = new ArrayList<>();
     34 
     35     private static final Runnable sAnimationCallbackRunnable = new Runnable() {
     36         @Override
     37         public void run() {
     38             for (int i = 0; i < sPendingRunnables.size(); i++) {
     39                 sHandler.post(sPendingRunnables.get(i));
     40             }
     41             sPendingRunnables.clear();
     42         }
     43     };
     44 
     45     /**
     46      * Executes {@code r} after performTraversals. Use this do to CPU heavy work for which the
     47      * timing is not critical for animation. The work is then scheduled at the same time
     48      * RenderThread is doing its thing, leading to better parallelization.
     49      *
     50      * <p>Needs to be called from the main thread.
     51      */
     52     public static void postAfterTraversal(Runnable r) {
     53         throwIfNotCalledOnMainThread();
     54         sPendingRunnables.add(r);
     55         postAnimationCallback();
     56     }
     57 
     58     /**
     59      * Removes a previously scheduled runnable.
     60      *
     61      * <p>Needs to be called from the main thread.
     62      */
     63     public static void removeCallbacks(Runnable r) {
     64         throwIfNotCalledOnMainThread();
     65         sPendingRunnables.remove(r);
     66         sHandler.removeCallbacks(r);
     67     }
     68 
     69     private static void postAnimationCallback() {
     70         sChoreographer.postCallback(Choreographer.CALLBACK_ANIMATION, sAnimationCallbackRunnable,
     71                 null);
     72     }
     73 
     74     private static void throwIfNotCalledOnMainThread() {
     75         if (!Looper.getMainLooper().isCurrentThread()) {
     76             throw new IllegalStateException("should be called from the main thread.");
     77         }
     78     }
     79 }
     80