1 /* 2 * Copyright (C) 2013 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.server; 18 19 import android.os.Handler; 20 import android.os.Looper; 21 import android.os.Process; 22 import android.os.Trace; 23 24 /** 25 * Shared singleton thread for showing UI. This is a foreground thread, and in 26 * additional should not have operations that can take more than a few ms scheduled 27 * on it to avoid UI jank. 28 */ 29 public final class UiThread extends ServiceThread { 30 private static final long SLOW_DISPATCH_THRESHOLD_MS = 100; 31 private static final long SLOW_DELIVERY_THRESHOLD_MS = 200; 32 private static UiThread sInstance; 33 private static Handler sHandler; 34 35 private UiThread() { 36 super("android.ui", Process.THREAD_PRIORITY_FOREGROUND, false /*allowIo*/); 37 } 38 39 @Override 40 public void run() { 41 // Make sure UiThread is in the fg stune boost group 42 Process.setThreadGroup(Process.myTid(), Process.THREAD_GROUP_TOP_APP); 43 super.run(); 44 } 45 46 private static void ensureThreadLocked() { 47 if (sInstance == null) { 48 sInstance = new UiThread(); 49 sInstance.start(); 50 final Looper looper = sInstance.getLooper(); 51 looper.setTraceTag(Trace.TRACE_TAG_SYSTEM_SERVER); 52 looper.setSlowLogThresholdMs( 53 SLOW_DISPATCH_THRESHOLD_MS, SLOW_DELIVERY_THRESHOLD_MS); 54 sHandler = new Handler(sInstance.getLooper()); 55 } 56 } 57 58 public static UiThread get() { 59 synchronized (UiThread.class) { 60 ensureThreadLocked(); 61 return sInstance; 62 } 63 } 64 65 public static Handler getHandler() { 66 synchronized (UiThread.class) { 67 ensureThreadLocked(); 68 return sHandler; 69 } 70 } 71 } 72
