1 /* 2 * Copyright (C) 2016 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 package com.android.settingslib.utils; 17 18 import android.os.Handler; 19 import android.os.Looper; 20 21 import java.util.concurrent.Callable; 22 import java.util.concurrent.ExecutorService; 23 import java.util.concurrent.Executors; 24 import java.util.concurrent.Future; 25 26 public class ThreadUtils { 27 28 private static volatile Thread sMainThread; 29 private static volatile Handler sMainThreadHandler; 30 private static volatile ExecutorService sThreadExecutor; 31 32 /** 33 * Returns true if the current thread is the UI thread. 34 */ isMainThread()35 public static boolean isMainThread() { 36 if (sMainThread == null) { 37 sMainThread = Looper.getMainLooper().getThread(); 38 } 39 return Thread.currentThread() == sMainThread; 40 } 41 42 /** 43 * Returns a shared UI thread handler. 44 */ getUiThreadHandler()45 public static Handler getUiThreadHandler() { 46 if (sMainThreadHandler == null) { 47 sMainThreadHandler = new Handler(Looper.getMainLooper()); 48 } 49 50 return sMainThreadHandler; 51 } 52 53 /** 54 * Checks that the current thread is the UI thread. Otherwise throws an exception. 55 */ ensureMainThread()56 public static void ensureMainThread() { 57 if (!isMainThread()) { 58 throw new RuntimeException("Must be called on the UI thread"); 59 } 60 } 61 62 /** 63 * Posts runnable in background using shared background thread pool. 64 * 65 * @Return A future of the task that can be monitored for updates or cancelled. 66 */ postOnBackgroundThread(Runnable runnable)67 public static Future postOnBackgroundThread(Runnable runnable) { 68 return getThreadExecutor().submit(runnable); 69 } 70 71 /** 72 * Posts callable in background using shared background thread pool. 73 * 74 * @Return A future of the task that can be monitored for updates or cancelled. 75 */ postOnBackgroundThread(Callable callable)76 public static Future postOnBackgroundThread(Callable callable) { 77 return getThreadExecutor().submit(callable); 78 } 79 80 /** 81 * Posts the runnable on the main thread. 82 */ postOnMainThread(Runnable runnable)83 public static void postOnMainThread(Runnable runnable) { 84 getUiThreadHandler().post(runnable); 85 } 86 87 /** 88 * Posts the runnable on the main thread with a delay. 89 */ postOnMainThreadDelayed(Runnable runnable, long delayMillis)90 public static void postOnMainThreadDelayed(Runnable runnable, long delayMillis) { 91 getUiThreadHandler().postDelayed(runnable, delayMillis); 92 } 93 getThreadExecutor()94 private static synchronized ExecutorService getThreadExecutor() { 95 if (sThreadExecutor == null) { 96 sThreadExecutor = Executors.newFixedThreadPool( 97 Runtime.getRuntime().availableProcessors()); 98 } 99 return sThreadExecutor; 100 } 101 } 102