Android AlarmManager - Scheduling a recurring Intent to fire off twice a day

问题

After reading lots of sample code into this matter, I'm trying to figure out the simplest way to achieve the following:

I want to be able to schedule an Intent that calls back to my Alarm BroadcastReceiver, which in turn fires off my Service. However, I want to set up so that it calls said Intent twice a day and to only schedule the alarms if they haven't already been set (likewise for canceling the alarms).

However, I am unsure if the following code is the correct way to set and cancel alarms.

//Static function for setting the alarm
//My midday calendar object (cal1)

...

//My evening calendar object (cal2)
AlarmManager alarms = (AlarmManager) context.getSystemService(Context.ALARM_SERVICE)
Intent myIntent = new Intent(context, MyAlarmReceiver.class);

    PendingIntent firstCallIntent = PendingIntent.getBroadcast(context, FIRST_CALL_ID, myIntent, PendingIntent.FLAG_NO_CREATE);
    PendingIntent secondCallIntent= PendingIntent.getBroadcast(context, SECOND_CALL_ID, myIntent, PendingIntent.FLAG_NO_CREATE);
    if(firstCallIntent == null){
        if(DEBUG){
            Log.d(TAG, "Setting Midday Alarm");
        }
        firstCallIntent = PendingIntent.getBroadcast(context, FIRST_CALL_ID, myIntent, 0);
        alarms.setInexactRepeating(AlarmManager.RTC_WAKEUP, cal1.getTimeInMillis(), AlarmManager.INTERVAL_DAY, firstCallIntent);
    }
    if(secondCallIntent == null){
        if(DEBUG){
            Log.d(TAG, "Setting Evening Alarm");
        }
        secondCallIntent = PendingIntent.getBroadcast(context, SECOND_CALL_ID, myIntent, 0);
        alarms.setInexactRepeating(AlarmManager.RTC_WAKEUP, cal2.getTimeInMillis(), AlarmManager.INTERVAL_DAY, secondCallIntent);
    }


//Static call to cancel the alarm.
AlarmManager alarms = (AlarmManager) context.getSystemService(Context.ALARM_SERVICE)
Intent myIntent = new Intent(context, MyAlarmReceiver.class);
PendingIntent firstCallIntent = PendingIntent.getBroadcast(context, FIRST_CALL_ID, myIntent, 0);
alarms.cancel(firstCallIntent);
firstCallIntent.cancel();
PendingIntent secondCallIntent = PendingIntent.getBroadcast(context, SECOND_CALL_ID, myIntent, 0);
alarms.cancel(secondCallIntent);
secondCallIntent.cancel();

回答1:

That seems alright to me, however instead of creating two calendar objects you could just set your interval to

AlarmManager.INTERVAL_DAY/2

unless your intents are doing different things.

Also,

alarms.cancel(firstCallIntent);
alarms.cancel(secondCallIntent);

should be enough to cancel all alarms of those types, no need for:

firstCallIntent.cancel();

Edit: Setting 2 calendar objects

//midday
Calendar cal1 = Calendar.getInstance();
cal1.set(Calendar.HOUR_OF_DAY, 12);
cal1.set(Calendar.MINUTE, 00);
cal1.set(Calendar.SECOND, 00);

//7pm
Calendar cal2 = Calendar.getInstance();
cal2.set(Calendar.HOUR_OF_DAY, 19);
cal2.set(Calendar.MINUTE, 00);
cal2.set(Calendar.SECOND, 00);

Calendar.getInstance() will return a calendar object and set it to the current system time. Each .set method changes a certain variable of that calendar object. So currently if it was 8pm, it would set the alarm for 12 and 7 that day, which would be no use. So if you want to set it for the next day, you'll need to use cal1.add(Calendar.DAY_OF_MONTH, 01); to add an extra day, setting for that time the next day. Hope this helps.

来源：https://stackoverflow.com/questions/8762934/android-alarmmanager-scheduling-a-recurring-intent-to-fire-off-twice-a-day

标签

android

alarmmanager

android-pendingintent