我正在制作一个Android警报应用程序但是当我关闭应用程序时警报被取消。这是我的代码

Question

公共类AlarmService扩展了IntentService {     private NotificationManager alarmNotificationManager;

public AlarmService() {
    super("AlarmService");
}

@Override
public void onHandleIntent(Intent intent) {
    sendNotification("Wake Up! Wake Up!");
}

private void sendNotification(String msg) {
    Log.d("AlarmService", "Preparing to send notification...: " + msg);
    alarmNotificationManager = (NotificationManager) this
            .getSystemService(Context.NOTIFICATION_SERVICE);

    PendingIntent contentIntent = PendingIntent.getActivity(this, 0,
            new Intent(this, AlarmActivity.class), 0);

    NotificationCompat.Builder alamNotificationBuilder = new NotificationCompat.Builder(
            this).setContentTitle("Alarm").setSmallIcon(R.drawable.ic_launcher)
            .setStyle(new NotificationCompat.BigTextStyle().bigText(msg))
            .setContentText(msg);


    alamNotificationBuilder.setContentIntent(contentIntent);
    alarmNotificationManager.notify(1, alamNotificationBuilder.build());
    Log.d("AlarmService", "Notification sent.");
}

}

公共类AlarmActivity扩展了Activity {

AlarmManager alarmManager;
private PendingIntent pendingIntent;
private TimePicker alarmTimePicker;
private static AlarmActivity inst;
private TextView alarmTextView;

public static AlarmActivity instance() {
    return inst;
}

@Override
public void onStart() {
    super.onStart();
    inst = this;
}

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_alarm);
    alarmTimePicker = (TimePicker) findViewById(R.id.alarmTimePicker);
    alarmTextView = (TextView) findViewById(R.id.alarmText);
    ToggleButton alarmToggle = (ToggleButton) findViewById(R.id.alarmToggle);
    alarmManager = (AlarmManager) getSystemService(ALARM_SERVICE);
    MediaPlayer mp;
    mp=MediaPlayer.create(AlarmActivity.this, R.raw.alarm);
    mp.start();
}

public void onToggleClicked(View view) {
    if (((ToggleButton) view).isChecked()) {
        Log.d("MyActivity", "Alarm On");
        Calendar calendar = Calendar.getInstance();
        calendar.set(Calendar.HOUR_OF_DAY, alarmTimePicker.getCurrentHour());
        calendar.set(Calendar.MINUTE, alarmTimePicker.getCurrentMinute());
        Intent myIntent = new Intent(AlarmActivity.this, AlarmReceiver.class);
        pendingIntent = PendingIntent.getBroadcast(AlarmActivity.this, 0, myIntent, 0);
        alarmManager.set(AlarmManager.RTC, calendar.getTimeInMillis(), pendingIntent);
    } else {
        alarmManager.cancel(pendingIntent);
        setAlarmText("Alarm Canceled");
        Log.d("MyActivity", "Alarm Off");


    }
}

public void setAlarmText(String alarmText) {
    alarmTextView.setText(alarmText);
}

}

公共类AlarmReceiver扩展了WakefulBroadcastReceiver {

@Override
public void onReceive(final Context context, Intent intent) {
    //this will update the UI with message
    AlarmActivity inst = AlarmActivity.instance();
    inst.setAlarmText("It's Time to Wake Up :)");

    //this will sound the alarm tone
    //this will sound the alarm once, if you wish to
    //raise alarm in loop continuously then use MediaPlayer and setLooping(true)
    Uri alarmUri = RingtoneManager.getDefaultUri(RingtoneManager.TYPE_ALARM);
    if (alarmUri == null) {
        alarmUri = RingtoneManager.getDefaultUri(RingtoneManager.TYPE_NOTIFICATION);
    }
    Ringtone ringtone = RingtoneManager.getRingtone(context, alarmUri);
    ringtone.play();

    //this will send a notification message
    ComponentName comp = new ComponentName(context.getPackageName(),
            AlarmService.class.getName());
    startWakefulService(context, (intent.setComponent(comp)));
    setResultCode(Activity.RESULT_OK);
}

}