在AlarmManager中取消警报

Question

In my code, I create an alarm as follows:

AlarmManager am = (AlarmManager) context.getSystemService(Context.ALARM_SERVICE);
Intent i = new Intent("mypackage.START_MONITORING_SERVICE");
PendingIntent pi = PendingIntent.getBroadcast(context, 0, i, 0);
long timeForNextStart = System.currentTimeMillis() + elapsedTime;
am.set(AlarmManager.RTC_WAKEUP, timeForNextStart, pi);

To cancel the alarm I do this:

AlarmManager am = (AlarmManager) context.getSystemService(Context.ALARM_SERVICE);
Intent intent = new Intent("mypackage.START_MONITORING_SERVICE");
PendingIntent pendingIntent = PendingIntent.getBroadcast(context, 0, intent, 0);
am.cancel(pendingIntent);

My question is whether this is the correct way to cancel ALL alarms of the same intent. The docs say:

Remove any alarms with a matching Intent. Any alarm, of any type, whose Intent matches this one (as defined by filterEquals(Intent)), will be canceled.

I'm not exactly sure what defines a "matching intent". If I create multiple alarms with the above code and then peform the cancel as shown, will it cancel ALL of the alarms I created?

Answer 1

您应该使用PendingIntent标志==> PendingIntent.FLAG_CANCEL_CURRENT第四个参数创建endingIntent实例方法。

PendingIntent pendingIntent = PendingIntent.getBroadcast(context, 0, intent,PendingIntent.FLAG_CANCEL_CURRENT);

Answer 2

Try this

AlarmManager alarmManager = (AlarmManager) context.getSystemService(Context.ALARM_SERVICE);

    Intent updateServiceIntent = new Intent(context, MyPendingIntentService.class);
    PendingIntent pendingUpdateIntent = PendingIntent.getService(context, 0, updateServiceIntent, 0);

    // Cancel alarms
    try {
        alarmManager.cancel(pendingUpdateIntent);
    } catch (Exception e) {
        Log.e(TAG, "AlarmManager update was not canceled. " + e.toString());
    }

Answer 3

My question is whether this is the correct way to cancel ALL alarms of the same intent?

I dont know if you aware of requestCode should be unique in for each pendingIntent for following syntax

public static PendingIntent getService (Context context, int requestCode, Intent intent, int flags)

I'm not exactly sure what defines a "matching intent".

Each pending intent map with its provided intent to trigger and each request code map with that intent .

We can say it can be same requestcode for two different pendingIntent which ideally having two different intents .

Remember , here if PendingIntent have a same requestCode for a same intent then it can be override or cancel according to int flags

If I create multiple alarms with the above code and then peform the cancel as shown, will it cancel ALL of the alarms I created?

To create a multiple alarm you have to give a different requestCode with the same intent . If you want to cancel those created alarm then you have to cancel them according requestCode

For example

To Create :

AlarmManager alarmManager = (AlarmManager) context.getSystemService(Context.ALARM_SERVICE);
For (int i= 0 ; i <5 ; i++){
PendingIntent contentIntent = PendingIntent.getBroadcast(TaskReminder.this, i,
                            new Intent(),PendingIntent.FLAG_UPDATE_CURRENT);
 alarmManager.set(AlarmManager.RTC_WAKEUP, timeForNextStart, contentIntent);

}

To cancel :

For (int i= 0 ; i <5 ; i++){
//Note here ' i ' is the requestCode which map each pendingIntent with there provided intent 
PendingIntent contentIntent = PendingIntent.getBroadcast(TaskReminder.this, i,
                            new Intent(),PendingIntent.FLAG_UPDATE_CURRENT);
 alarmManager.cancel(contentIntent);

}