Why do Android alarms fire at the same time?

Question

Below is a pretty simple method that takes a Date and an id for an alarm to be fired which starts a countdown. For some reason I don't understand, if I call it once with one date and id 0 and call it again with another date and id 1 (i.e., two different countdowns), Android will fire both alarms at the same time (specifically the first date passed with id 0) so both countdowns start at the same time.

Can anyone tell me why and how to fix it? Thanks!

public void setCountdownAlarm(Date fireTime, int id)
{
    // startCountdown will be called at fireTime
    BroadcastReceiver startCountdown = new BroadcastReceiver() {
        @Override public void onReceive( Context context, Intent theIntent )
        {
            countdownTimer = new Timer();
            countdownTimer.schedule(new TimerTask() {
                @Override
                public void run() {
                    onSecondTick(showtime);
                }
            }, 0, 100); // call every 10th of a second
        }
    };

    this.registerReceiver( startCountdown, new IntentFilter("com.counter.app.CountActivity.COUNT") );
    Intent intent = new Intent("com.counter.app.CountActivity.COUNT");
    PendingIntent pintent = PendingIntent.getBroadcast( this, id, intent, 0 );
    AlarmManager manager = (AlarmManager)(this.getSystemService( Context.ALARM_SERVICE ));

    if (Build.VERSION.SDK_INT >= 19)
        manager.setExact(AlarmManager.RTC_WAKEUP, fireTime.getTime(), pintent);
    else
        manager.set(AlarmManager.RTC_WAKEUP, fireTime.getTime(), pintent);
}

Editing to say that when I waited for the second alarm to fire, Android actually calls startCountdown twice -- once again for each alarm. Help!

Answer 1

I figured out what I did wrong. As explained in answers to similar questions, the second parameter of PendingIntent.getBroadcast (requestCode) must be unique if you want to get a unique pending intent. I took care of that by passing "id".

The second problem was that I registered the BroadcastReceiver each time I called setCountdownAlarm. The BroadcastReceiver should only be registered once, typically in the onCreate method of the activity.