如何取消Android应用程序中的警报

Question

我坚持在Android应用程序中停止（取消）闹钟。我会在这里粘贴我的代码，请帮帮我。

我的MainActivity.Java类：

public class MainActivity extends AppCompatActivity implements View.OnClickListener {
  EditText time_et;
  Button start_alarm_btn, stop_alarm_btn;
  Intent intent;
  PendingIntent pendingIntent;
  AlarmManager alarmManager;
  AlaramReceiver alarmReceiver;
  @Override
  protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
    setSupportActionBar(toolbar);
    time_et = (EditText) findViewById(R.id.set_time_et);
    start_alarm_btn = (Button) findViewById(R.id.start_alarm);
    stop_alarm_btn = (Button) findViewById(R.id.stop_alarm);
    start_alarm_btn.setOnClickListener(this);
    stop_alarm_btn.setOnClickListener(this);
    alarmReceiver= new AlaramReceiver();
}

public void setAlarm(View view) {
    if (!time_et.getText().toString().equals("")) {
        int i = Integer.parseInt(time_et.getText().toString());
        intent = new Intent(this, AlaramReceiver.class);
        pendingIntent = PendingIntent.getBroadcast(
            this.getApplicationContext(), 280192, intent, PendingIntent.FLAG_CANCEL_CURRENT);
        alarmManager= (AlarmManager) getSystemService(ALARM_SERVICE);
        alarmManager.set(AlarmManager.RTC_WAKEUP, Calendar.getInstance().getTimeInMillis() + (i * 1000), pendingIntent);
        Toast.makeText(this, "Alarm will set in " + i + " seconds",
            Toast.LENGTH_LONG).show();
    } else {
        Toast.makeText(this,"Please Provide time ",Toast.LENGTH_SHORT).show();
    }
}

@Override
protected void onStop() {
    super.onStop();
    if (alarmManager !=null){
        pendingIntent.cancel();
        alarmManager.cancel(pendingIntent);
        Toast.makeText(this, "alarm disabled!!!", Toast.LENGTH_SHORT).show();
    }
}

@Override
public boolean onCreateOptionsMenu(Menu menu) {
    // Inflate the menu; this adds items to the action bar if it is present.
    getMenuInflater().inflate(R.menu.menu_main, menu);
    return true;
}

@Override
public boolean onOptionsItemSelected(MenuItem item) {
    // Handle action bar item clicks here. The action bar will
    // automatically handle clicks on the Home/Up button, so long
    // as you specify a parent activity in AndroidManifest.xml.
    int id = item.getItemId();
   //noinspection SimplifiableIfStatement
    if (id == R.id.action_settings) {
        return true;
    }
    return super.onOptionsItemSelected(item);
}

@Override
public void onClick(View view) {
    if(view.getId() == R.id.start_alarm){
        setAlarm(view);
    }
    if (view.getId() == R.id.stop_alarm){
        pendingIntent.cancel();
        alarmManager.cancel(pendingIntent);
        Toast.makeText(this, "Alarm is disabled", Toast.LENGTH_SHORT).show();
    }
}

}

我的AlarmReceiver.java类：

public class AlaramReceiver extends BroadcastReceiver {
MediaPlayer mp;
Ringtone ringtoneSound;

public AlaramReceiver() {
}

@Override
public void onReceive(Context context, Intent intent) {
    // TODO: This method is called when the BroadcastReceiver is receiving
    // an Intent broadcast.
    Uri ringtoneUri = RingtoneManager.getDefaultUri(RingtoneManager.TYPE_ALARM);
    ringtoneSound = RingtoneManager.getRingtone(context.getApplicationContext(), ringtoneUri);
    if (ringtoneSound != null) {
        ringtoneSound.play();
    }
    Toast.makeText(context, "Alarm....", Toast.LENGTH_LONG).show();

我的Content_main.xml文件：

public class AlaramReceiver extends BroadcastReceiver {
MediaPlayer mp;
Ringtone ringtoneSound;

public AlaramReceiver() {
}

@Override
public void onReceive(Context context, Intent intent) {
    // TODO: This method is called when the BroadcastReceiver is receiving
    // an Intent broadcast.
    Uri ringtoneUri = RingtoneManager.getDefaultUri(RingtoneManager.TYPE_ALARM);
    ringtoneSound = RingtoneManager.getRingtone(context.getApplicationContext(), ringtoneUri);
    if (ringtoneSound != null) {
        ringtoneSound.play();
    }
    Toast.makeText(context, "Alarm....", Toast.LENGTH_LONG).show();

我不知道我在哪里犯这个错误。请帮帮我......提前致谢。