Android setAlarmClock triggering immediately

Question

I created a simple application to try out setAlarmClock(). There is only a single button in the MainActivity, and it calls setAlarm when clicked.

The code is below.

MainActivity

public class MainActivity extends AppCompatActivity {
    private static final String TAG = "alarmclock.MainActivity";

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

    public void setAlarm(View view) {
        Context context = getApplicationContext();
        Intent intent = new Intent(context, AlarmReceiver.class);
        PendingIntent pendingIntent = PendingIntent.getBroadcast(context, 0, intent, 0);

        long nextTrigger = SystemClock.elapsedRealtime()+10*1000;
        Log.i(TAG, SystemClock.elapsedRealtime() + ": scheduling next alarm at " + nextTrigger);

        AlarmManager alarmManager = (AlarmManager) getSystemService(ALARM_SERVICE);

        AlarmManager.AlarmClockInfo ac = new AlarmManager.AlarmClockInfo(nextTrigger, null);
        alarmManager.setAlarmClock(ac, pendingIntent);
    }
}

AlarmReceiver

public class AlarmReceiver extends BroadcastReceiver {
    private static final String TAG = "alarmclock.AlarmReceiver";

    @Override
    public void onReceive(Context context, Intent intent) {
        Log.i(TAG, SystemClock.elapsedRealtime() + " in AlarmReceiver onReceive()");
    }
}

I am basically triggering the alarm for 10seconds later, but for some reason it's triggering immediately.

2020-09-21 22:09:56.664 17910-17910/com.example.alarmclock I/alarmclock.MainActivity: 3362358: scheduling next alarm at 3372358
2020-09-21 22:09:56.687 17910-17910/com.example.alarmclock I/alarmclock.AlarmReceiver: 3362382 in AlarmReceiver onReceive()

If I use setExactAndAllowWhileIdle the same code seems to work fine. But I am specifically wanting to try out setAlarmClock.

Answer 1

The AlarmClockInfo requires a wall time:

time at which the underlying alarm is triggered in wall time milliseconds since the epoch

but you are using elapsedRealtime() time so use System.currentTimeMillis to fix the issue.