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.ExecutorService; 22 import java.util.concurrent.Executors; 23 24 public class ThreadUtils { 25 26 private static volatile Thread sMainThread; 27 private static volatile Handler sMainThreadHandler; 28 private static volatile ExecutorService sSingleThreadExecutor; 29 30 /** 31 * Returns true if the current thread is the UI thread. 32 */ 33 public static boolean isMainThread() { 34 if (sMainThread == null) { 35 sMainThread = Looper.getMainLooper().getThread(); 36 } 37 return Thread.currentThread() == sMainThread; 38 } 39 40 /** 41 * Returns a shared UI thread handler. 42 */ 43 public static Handler getUiThreadHandler() { 44 if (sMainThreadHandler == null) { 45 sMainThreadHandler = new Handler(Looper.getMainLooper()); 46 } 47 48 return sMainThreadHandler; 49 } 50 51 /** 52 * Checks that the current thread is the UI thread. Otherwise throws an exception. 53 */ 54 public static void ensureMainThread() { 55 if (!isMainThread()) { 56 throw new RuntimeException("Must be called on the UI thread"); 57 } 58 } 59 60 /** 61 * Posts runnable in background using shared background thread pool. 62 */ 63 public static void postOnBackgroundThread(Runnable runnable) { 64 if (sSingleThreadExecutor == null) { 65 sSingleThreadExecutor = Executors.newSingleThreadExecutor(); 66 } 67 sSingleThreadExecutor.execute(runnable); 68 } 69 70 /** 71 * Posts the runnable on the main thread. 72 */ 73 public static void postOnMainThread(Runnable runnable) { 74 getUiThreadHandler().post(runnable); 75 } 76 77 } 78
