1 /* 2 * Copyright (C) 2006 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 android.os; 18 19 /** 20 * Handy class for starting a new thread that has a looper. The looper can then be 21 * used to create handler classes. Note that start() must still be called. 22 */ 23 public class HandlerThread extends Thread { 24 private int mPriority; 25 private int mTid = -1; 26 private Looper mLooper; 27 HandlerThread(String name)28 public HandlerThread(String name) { 29 super(name); 30 mPriority = Process.THREAD_PRIORITY_DEFAULT; 31 } 32 33 /** 34 * Constructs a HandlerThread. 35 * @param name 36 * @param priority The priority to run the thread at. The value supplied must be from 37 * {@link android.os.Process} and not from java.lang.Thread. 38 */ HandlerThread(String name, int priority)39 public HandlerThread(String name, int priority) { 40 super(name); 41 mPriority = priority; 42 } 43 44 /** 45 * Call back method that can be explicitly over ridden if needed to execute some 46 * setup before Looper loops. 47 */ onLooperPrepared()48 protected void onLooperPrepared() { 49 } 50 run()51 public void run() { 52 mTid = Process.myTid(); 53 Looper.prepare(); 54 synchronized (this) { 55 mLooper = Looper.myLooper(); 56 Process.setThreadPriority(mPriority); 57 notifyAll(); 58 } 59 onLooperPrepared(); 60 Looper.loop(); 61 mTid = -1; 62 } 63 64 /** 65 * This method returns the Looper associated with this thread. If this thread not been started 66 * or for any reason is isAlive() returns false, this method will return null. If this thread 67 * has been started, this method will block until the looper has been initialized. 68 * @return The looper. 69 */ getLooper()70 public Looper getLooper() { 71 if (!isAlive()) { 72 return null; 73 } 74 75 // If the thread has been started, wait until the looper has been created. 76 synchronized (this) { 77 while (isAlive() && mLooper == null) { 78 try { 79 wait(); 80 } catch (InterruptedException e) { 81 } 82 } 83 } 84 return mLooper; 85 } 86 87 /** 88 * Ask the currently running looper to quit. If the thread has not 89 * been started or has finished (that is if {@link #getLooper} returns 90 * null), then false is returned. Otherwise the looper is asked to 91 * quit and true is returned. 92 */ quit()93 public boolean quit() { 94 Looper looper = getLooper(); 95 if (looper != null) { 96 looper.quit(); 97 return true; 98 } 99 return false; 100 } 101 102 /** 103 * Returns the identifier of this thread. See Process.myTid(). 104 */ getThreadId()105 public int getThreadId() { 106 return mTid; 107 } 108 } 109