Android Set Multiple Alarms

Question

I'm trying to implement an Android app that needs to alarm (or to alert) multiple times along the time.

I've already searched, but the nearest I found was a fixed-number of alarms set, and I guess the example didn't work.

What I want to know if there is exists an approach to dynamically set multiple alarms, like an Array of alarms and then to trigger those alarms in their specific timestamps.

Answer 1

You can set the repetition of the alarm:

in this case:

public void AddAlarm(int requestCode,MutableDateTime dueDate,int repeat) {
        Intent intent = new Intent(context, AlarmReceiver.class);
        intent.putExtra(Constants.RECORD_ID, requestCode);
        intent.putExtra("REPEAT", repeat);
        PendingIntent operation = PendingIntent.getBroadcast(context, requestCode, intent,  PendingIntent.FLAG_ONE_SHOT );
        MutableDateTime due = dueDate.toMutableDateTime();
        switch(repeat){
        case NO_REPEAT:
            due.addMinutes(0);
            break;
        case DAILY:

            due.addDays(1); 
            break;
        case WEEKLY:
            due.addWeeks(1);
            break;
        case MONTHLY:
            due.addMonths(1);
            break;
        case MONTHLY_2:
            due.addWeeks(5);            
            break;
        case YEARLY:
            due.addYears(1);
            break;
        }
        due.add(-(dueDate.getMillis()));
        due.setSecondOfMinute(0);
        dueDate.setSecondOfMinute(0);
        alarm.cancel(operation);
        alarm.set(AlarmManager.RTC_WAKEUP, dueDate.getMillis(), operation);
        alarm.setRepeating(AlarmManager.RTC_WAKEUP, dueDate.getMillis(), due.getMillis(), operation);
}

Answer 2

To dynamically set up multiple alarms, the approach which I used is that I created a single alarm. Then in my alarm setting class, a static integer (to be used as requestcode) is initialized which will be incremented each time from my main activity whenever I click on "add alarm" button in my main activity. E.g.

MainActivity.java

public class MainActivity extends AppCompatActivity {

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
}

public void addAlarmClick(View v) {
    AlarmActivity.broadcastCode++;
    startActivity(new Intent(this, AlarmActivity.class));
}
}

AlarmActivity.java

public class AlarmActivity extends AppCompatActivity {`

public static int broadcastCode=0;
/*some code here*/
Intent myIntent = new Intent(AlarmActivity.this, AlarmReceiver.class);
pendingIntent = PendingIntent.getBroadcast(AlarmActivity.this,
                            broadcastCode, myIntent, 0);

I hope this will help.

Answer 3

If you want to set multiple alarms (repeating or single), then you just need to create their PendingIntents with different requestCode. If requestCode is the same, then the new alarm will overwrite the old one.

Here is the code to create multiple single alarms and keep them in ArrayList. I keep PendingIntent's in the array because that's what you need to cancel your alarm.

// context variable contains your `Context`
AlarmManager mgrAlarm = (AlarmManager) context.getSystemService(ALARM_SERVICE);
ArrayList<PendingIntent> intentArray = new ArrayList<PendingIntent>();

for(i = 0; i < 10; ++i)
{
   Intent intent = new Intent(context, OnAlarmReceiver.class);
   // Loop counter `i` is used as a `requestCode`
   PendingIntent pendingIntent = PendingIntent.getBroadcast(context, i, intent, 0);
   // Single alarms in 1, 2, ..., 10 minutes (in `i` minutes)
   mgrAlarm.set(AlarmManager.ELAPSED_REALTIME_WAKEUP, 
                SystemClock.elapsedRealtime() + 60000 * i, 
                pendingIntent); 

   intentArray.add(pendingIntent);
}

Also, see this question: How to set more than one alarms at a time in android?.