线程的DefaultUncaughtExceptionHandler无法捕获AlertDialog onClick（）方法中引发的异常

Question

我设置默认UncaughtExceptionHandler在我当前线程Activity的onCreate()和抛出RunTimeException从我的AlertDialog的onClick()监听器，但异常没有被捕获。 我还尝试从onCreateOptionsMenu()和onOptionsItemSelected()引发异常，但未捕获到异常。 但是，当从onCreate()或onResume()抛出该错误时，将捕获该错误。

这是我的活动：

public class MainActivity extends AppCompatActivity implements DialogInterface.OnClickListener {

    private static final String TAG = "MainActivity";

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        Thread.setDefaultUncaughtExceptionHandler(new DefExcHandler());
        Log.d(TAG, "onCreate: "+Thread.currentThread().getName()+" "+Thread.currentThread().getId());

        AlertDialog.Builder builder = new AlertDialog.Builder(this);
        builder.setNeutralButton("CRASH", this);
        AlertDialog dialog = builder.create();
        dialog.show();
        dialog.setCancelable(false);
        dialog.setCanceledOnTouchOutside(false);
    }

    @Override
    public void onClick(DialogInterface dialog, int which) {
        dialog.dismiss();
        Log.d(TAG, "onClick: "+Thread.currentThread().getName()+" "+Thread.currentThread().getId());
        throw new RuntimeException();
    }
}

这是我的异常处理程序：

public class DefExcHandler implements Thread.UncaughtExceptionHandler {

    private static final String TAG = "DefExcHandler";

    public DefExcHandler() {
        Log.d(TAG, "DefaultExceptionHandler: ");
    }

    @Override
    public void uncaughtException(Thread thread, Throwable ex) {
        Log.d(TAG, "Uncaught exception caught: "+ex.getMessage()+" "+ex.getCause().toString());
    }
}

根据我在活动中创建的日志消息，在onCreate()和onClick() ，线程是相同的：

09-27 15:00:57.260 10667-10667/a.b.c D/MainActivity: onCreate: main 1
09-27 15:01:52.680 10667-10667/a.b.c D/MainActivity: onClick: main 1

为什么从onClick() ， onCreateOptionsMenu()或onOptionsItemSelected()抛出异常时未捕获到异常？

Answer 1

我试图重现该应用程序的行为。 DefExcHandler实例似乎没有被记录，因为它没有记录任何东西，但是我尝试了另外两个DefExcHandler ：断点和文件创建。

请尝试在uncaughtException()设置一个断点。 我相信它将停止您代码中的执行。 我在下面编写了一个示例，该示例使用文件作为标志来指示未捕获的异常处理程序确实正在被调用。

总而言之，似乎正在调用DefExcHandler.uncaughtException() ，但是Android由于某些未知原因（可能是内部竞争条件DefExcHandler.uncaughtException()而无法进行日志记录。

// Example that assures that an UncaughtExceptionHandler
// is being invoked by flagging execution with file creation.

public class MainActivity extends ... implements ... {

    private File mCrashFile;

    @Override
    protected void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);

        mCrashFile = new File(getFilesDir(), "crash");

        // Crash file existence means the application has crashed before.
        Log.d(TAG, "crash file exists: " + mCrashFile.exists());

        // Clear crash flag.
        if (mCrashFile.exists()) {
            Log.d(TAG, "crash file delete: " + mCrashFile.delete());
        }

        Thread.setDefaultUncaughtExceptionHandler(new DefExcHandler());

        ...

    }

    private class DefExcHandler implements Thread.UncaughtExceptionHandler {

        @Override
        public void uncaughtException(Thread thread, Throwable ex) {

            // Set crash flag.
            try {
                mCrashFile.createNewFile();
            } catch (IOException e) {
                // dunno if it really prints anything
                e.printStackTrace();
            }
        }
    }
}