3.31

安卓应用的性能监控与 Crash 捕获
实时监控应用性能并捕获 Crash 信息，有助于及时发现和修复应用中的问题。​

1. 性能监控​
   使用 Android 的 StrictMode 检测代码中的违规操作，例如主线程中的磁盘或网络操作：​
   ​
   StrictMode.setThreadPolicy(new StrictMode.ThreadPolicy.Builder()​
   .detectDiskReads()​
   .detectDiskWrites()​
   .detectNetwork()​
   .penaltyLog()​
   .build());​
   StrictMode.setVmPolicy(new StrictMode.VmPolicy.Builder()​
   .detectLeakedSqlLiteObjects()​
   .penaltyLog()​
   .penaltyDeath()​
   .build());​
   ​
   使用 TraceView 进行方法调用性能分析：​
   ​
   Debug.startMethodTracing("my_trace");​
   // 执行需要分析的代码​
   Debug.stopMethodTracing();​
   ​
2. Crash 捕获​
   自定义 UncaughtExceptionHandler 捕获未处理的异常：​
   ​
   Thread.setDefaultUncaughtExceptionHandler(new Thread.UncaughtExceptionHandler() {​
   @Override​
   public void uncaughtException(Thread t, Throwable e) {​
   // 保存Crash日志到文件​
   File file = new File(Environment.getExternalStorageDirectory(), "crash.log");​
   try (FileWriter writer = new FileWriter(file, true)) {​
   e.printStackTrace(new PrintWriter(writer));​
   } catch (IOException ex) {​
   ex.printStackTrace();​
   }​
   // 重启应用或提示用户​
   Intent intent = getPackageManager().getLaunchIntentForPackage(getPackageName());​
   PendingIntent pendingIntent = PendingIntent.getActivity(​
   MainActivity.this, 0, intent, PendingIntent.FLAG_ONE_SHOT);​
   AlarmManager alarmManager = (AlarmManager) getSystemService(Context.ALARM_SERVICE);​
   alarmManager.set(AlarmManager.RTC, System.currentTimeMillis() + 1000, pendingIntent);​
   System.exit(2);​
   }​
   });​