Android卡顿检测方案
ty647226
7年前
<p>应用的流畅度最直接的影响了App的用户体验,轻微的卡顿有时导致用户的界面操作需要等待一两秒钟才能生效,严重的卡顿则导致系统直接弹出ANR的提示窗口,让用户选择要继续等待还是关闭应用。</p> <p><img src="https://simg.open-open.com/show/76212791f4ab428d7b159562e2fc2b51.png"></p> <p>所以,如果想要提升用户体验,就需要尽量避免卡顿的产生,否则用户经历几次类似场景之后,只会动动手指卸载应用,再顺手到应用商店给个差评。关于卡顿的分析方案,已经有以下两种:</p> <ul> <li>分析trace文件。通过分析系统的/data/anr/traces.txt,来找到导致UI线程阻塞的源头,这种方案比较适合开发过程中使用,而不适合线上环境;</li> <li>使用BlockCanary开源方案。其原理是利用Looper中的loop输出的>>>>> Dispatching to和<<<<< Finished to这样的log,这种方案适合开发过程和上线的时候使用,但也有个弊端,就是如果系统移除了前面两个log,检测可能会面临失效;</li> </ul> <p>下面就开始说本文要提及的卡顿检测实现方案,原理简单,代码量也不多,只有BlockLooper和BlockError两个类。</p> <h2>基本使用</h2> <p>在Application中调用BlockLooper.initialize进行一些参数初始化,具体参数项可以参照BlockLooper中的Configuration静态内部类,当发生卡顿时,则会在回调(非UI线程中)OnBlockListener。</p> <pre> <code class="language-java">public class AndroidPerformanceToolsApplicationextends Application{ private final static String TAG = AndroidPerformanceToolsApplication.class.getSimpleName(); @Override public void onCreate(){ super.onCreate(); // 初始化相关配置信息 BlockLooper.initialize(new BlockLooper.Builder(this) .setIgnoreDebugger(true) .setReportAllThreadInfo(true) .setSaveLog(true) .setOnBlockListener(new BlockLooper.OnBlockListener() {//回调在非UI线程 @Override public void onBlock(BlockError blockError){ blockError.printStackTrace();//把堆栈信息输出到控制台 } }) .build()); } } </code></pre> <p>在选择要启动(停止)卡顿检测的时候,调用对应的API</p> <pre> <code class="language-java">BlockLooper.getBlockLooper().start();//启动检测 BlockLooper.getBlockLooper().stop();//停止检测 </code></pre> <p>使用上很简单,接下来看一下效果演示和源码实现。</p> <h2>效果演示</h2> <p>制造一个UI阻塞效果</p> <p><img src="https://simg.open-open.com/show/ffd144f0076ea393f641124dc4037d18.gif"></p> <p>看看AS控制台输出的整个堆栈信息</p> <p><img src="https://simg.open-open.com/show/3d931347d0705057b89bf329f620f97f.png"></p> <p>定位到对应阻塞位置的源码</p> <p><img src="https://simg.open-open.com/show/0c8fc437b0f05f824679e29a275484c5.png"></p> <p>当然,对线程的信息BlockLooper也不仅输出到控制台,也会帮你缓存到SD上对应的应用缓存目录下,在SD卡上的/Android/data/对应App包名/cache/block/下可以找到,文件名是发生卡顿的时间点,后缀是trace。</p> <p><img src="https://simg.open-open.com/show/c6f2664f0d4e6cbc517c5ed7fcfab740.gif"></p> <h2>源码解读</h2> <p>当App在5s内无法对用户做出的操作进行响应时,系统就会认为发生了ANR。BlockLooper实现上就是利用了这个定义,它继承了Runnable接口,通过initialize传入对应参数配置好后,通过BlockLooper的start()创建一个Thread来跑起这个Runnable,在没有stop之前,BlockLooper会一直执行run方法中的循环,执行步骤如下:</p> <ul> <li>Step1. 判断是否停止检测UI线程阻塞,未停止则进入Step2;</li> <li>Step2. 使用uiHandler不断发送ticker这个Runnable,ticker会对tickCounter进行累加;</li> <li>Step3. BlockLooper进入指定时间的sleep(frequency是在initialize时传入,最小不能低于5s);</li> <li>Step4. 如果UI线程没有发生阻塞,则sleep过后,tickCounter一定与原来的值不相等,否则一定是UI线程发生阻塞;</li> <li>Step5. 发生阻塞后,还需判断是否由于Debug程序引起的,不是则进入Step6;</li> <li>Step6. 回调OnBlockListener,以及选择保存当前进程中所有线程的堆栈状态到SD卡等;</li> </ul> <pre> <code class="language-java">public class BlockLooperimplements Runnable{ ... private Handler uiHandler = new Handler(Looper.getMainLooper()); private Runnable ticker = new Runnable() { @Override public void run(){ tickCounter = (tickCounter + 1) % Integer.MAX_VALUE; } }; ... private void init(Configuration configuration){ this.appContext = configuration.appContext; this.frequency = configuration.frequency < DEFAULT_FREQUENCY ? DEFAULT_FREQUENCY : configuration.frequency; this.ignoreDebugger = configuration.ignoreDebugger; this.reportAllThreadInfo = configuration.reportAllThreadInfo; this.onBlockListener = configuration.onBlockListener; this.saveLog = configuration.saveLog; } @Override public void run(){ int lastTickNumber; while (!isStop) { //Step1 lastTickNumber = tickCounter; uiHandler.post(ticker); //Step2 try { Thread.sleep(frequency); //Step3 } catch (InterruptedException e) { e.printStackTrace(); break; } if (lastTickNumber == tickCounter) { //Step4 if (!ignoreDebugger && Debug.isDebuggerConnected()) { //Step5 Log.w(TAG, "当前由调试模式引起消息阻塞引起ANR,可以通过setIgnoreDebugger(true)来忽略调试模式造成的ANR"); continue; } BlockError blockError; //Step6 if (!reportAllThreadInfo) { blockError = BlockError.getUiThread(); } else { blockError = BlockError.getAllThread(); } if (onBlockListener != null) { onBlockListener.onBlock(blockError); } if (saveLog) { if (StorageUtils.isMounted()) { File logDir = getLogDirectory(); saveLogToSdcard(blockError, logDir); } else { Log.w(TAG, "sdcard is unmounted"); } } } } } ... public synchronized void start(){ if (isStop) { isStop = false; Thread blockThread = new Thread(this); blockThread.setName(LOOPER_NAME); blockThread.start(); } } public synchronized void stop(){ if (!isStop) { isStop = true; } } ... ... } </code></pre> <p>介绍完BlockLooper后,再简单说一下BlockError的代码,主要有getUiThread和getAllThread两个方法,分别用户获取UI线程和进程中所有线程的堆栈状态信息,当捕获到BlockError时,会在OnBlockListener中以参数的形式传递回去。</p> <pre> <code class="language-java">public class BlockErrorextends Error{ private BlockError(ThreadStackInfoWrapper.ThreadStackInfo threadStackInfo){ super("BlockLooper Catch BlockError", threadStackInfo); } public staticBlockErrorgetUiThread(){ Thread uiThread = Looper.getMainLooper().getThread(); StackTraceElement[] stackTraceElements = uiThread.getStackTrace(); ThreadStackInfoWrapper.ThreadStackInfo threadStackInfo = new ThreadStackInfoWrapper(getThreadNameAndState(uiThread), stackTraceElements) .new ThreadStackInfo(null); return new BlockError(threadStackInfo); } public staticBlockErrorgetAllThread(){ final Thread uiThread = Looper.getMainLooper().getThread(); Map<Thread, StackTraceElement[]> stackTraceElementMap = new TreeMap<Thread, StackTraceElement[]>(new Comparator<Thread>() { @Override public int compare(Thread lhs, Thread rhs){ if (lhs == rhs) { return 0; } else if (lhs == uiThread) { return 1; } else if (rhs == uiThread) { return -1; } return rhs.getName().compareTo(lhs.getName()); } }); for (Map.Entry<Thread, StackTraceElement[]> entry : Thread.getAllStackTraces().entrySet()) { Thread key = entry.getKey(); StackTraceElement[] value = entry.getValue(); if (value.length > 0) { stackTraceElementMap.put(key, value); } } //Fix有时候Thread.getAllStackTraces()不包含UI线程的问题 if (!stackTraceElementMap.containsKey(uiThread)) { stackTraceElementMap.put(uiThread, uiThread.getStackTrace()); } ThreadStackInfoWrapper.ThreadStackInfo threadStackInfo = null; for (Map.Entry<Thread, StackTraceElement[]> entry : stackTraceElementMap.entrySet()) { Thread key = entry.getKey(); StackTraceElement[] value = entry.getValue(); threadStackInfo = new ThreadStackInfoWrapper(getThreadNameAndState(key), value). new ThreadStackInfo(threadStackInfo); } return new BlockError(threadStackInfo); } ... } </code></pre> <p> </p> <p>来自:http://blog.coderclock.com/2017/06/04/android/AndroidPerformanceTools-BlockLooper/</p> <p> </p>