1 /* 2 * Copyright (C) 2017 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.launcher3.util; 18 19 import android.os.Looper; 20 import android.os.MessageQueue; 21 22 import com.android.launcher3.Utilities; 23 24 /** 25 * Utility class to block execution until the UI looper is idle. 26 */ 27 public class LooperIdleLock implements MessageQueue.IdleHandler, Runnable { 28 29 private final Object mLock; 30 31 private boolean mIsLocked; 32 LooperIdleLock(Object lock, Looper looper)33 public LooperIdleLock(Object lock, Looper looper) { 34 mLock = lock; 35 mIsLocked = true; 36 if (Utilities.ATLEAST_MARSHMALLOW) { 37 looper.getQueue().addIdleHandler(this); 38 } else { 39 // Looper.myQueue() only gives the current queue. Move the execution to the UI thread 40 // so that the IdleHandler is attached to the correct message queue. 41 new LooperExecutor(looper).execute(this); 42 } 43 } 44 45 @Override run()46 public void run() { 47 Looper.myQueue().addIdleHandler(this); 48 } 49 50 @Override queueIdle()51 public boolean queueIdle() { 52 synchronized (mLock) { 53 mIsLocked = false; 54 mLock.notify(); 55 } 56 return false; 57 } 58 awaitLocked(long ms)59 public boolean awaitLocked(long ms) { 60 if (mIsLocked) { 61 try { 62 // Just in case mFlushingWorkerThread changes but we aren't woken up, 63 // wait no longer than 1sec at a time 64 mLock.wait(ms); 65 } catch (InterruptedException ex) { 66 // Ignore 67 } 68 } 69 return mIsLocked; 70 } 71 } 72