Android：从通知重定向到活动导致应用崩溃

Question

我有一个检测噪音水平的应用程序，当在后台运行时噪音水平过高时，它会发出通知。当我单击通知时，它会将我重定向到“活动”，但是录音功能已停止。当我单击通知后尝试从活动中再次启动声音计时，它崩溃了。听和停止按钮不起作用。这就是我所拥有的：

 public void tripAlarm(double Db){

        alertActive = true;
        mRecorder.pause();
        if (Build.VERSION.SDK_INT >= 26) {
            ((Vibrator) getSystemService(VIBRATOR_SERVICE)).vibrate(VibrationEffect.createOneShot(150, VibrationEffect.DEFAULT_AMPLITUDE));
        }else {
            ((Vibrator) getSystemService(VIBRATOR_SERVICE)).vibrate(150);
        }
        AlertDialog.Builder builder = new AlertDialog.Builder(MainActivity.this);

        builder.setCancelable(false);
        builder.setTitle("Sound Levels Are Too High");
        builder.setMessage((df.format(Db)) + " dB");




        builder.setPositiveButton("OK", new DialogInterface.OnClickListener() {
            @Override
            public void onClick(DialogInterface dialogInterface, int i) {
                // alertTextView.setVisibility(View.VISIBLE);
                alertActive = false;
                mRecorder.resume();
            }
        });
        builder.show();

        //Show the notification if the noise levels get too loud in the foreground
        String title = "Sound Meter";
        String message = "Sound levels are too high";

        //Created an Intent for Main Activity
        Intent intent = new Intent(this, MainActivity.class);
        intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK | Intent.FLAG_ACTIVITY_CLEAR_TASK);
        PendingIntent pendingIntent = PendingIntent.getActivity(this, 0, intent, 0);

        Notification notification = new NotificationCompat.Builder(this,CHANNEL_ID)
                .setSmallIcon(R.drawable.ic_android)
                .setContentTitle(title)
                .setContentText(message)
                .setPriority(NotificationCompat.PRIORITY_DEFAULT)
                .setCategory(NotificationCompat.CATEGORY_ALARM)
                .setContentIntent(pendingIntent)
                .build();

                notificationManager.notify(1,notification);

}

单击通知后，我希望它可以带我回到mainActivity，并且录音功能像以前一样正常工作。