Schedule a pending intent in android.

Backoff.java

import android.app.AlarmManager;
import android.app.PendingIntent;
import android.content.Context;
import android.os.SystemClock;
import android.util.Log;
 
public class Backoff
{
	private static String TAG = "Backoff";
	
	private static long INITIAL_RETRY_TIME = 400;
	private static int MAX_RETRIES = 20;

	/*
		 0:       400 ms (0.0 hr)
		 1:       800 ms (0.0 hr)
		 2:      1600 ms (0.0 hr)
		 3:      3200 ms (0.0 hr)
		 4:      6400 ms (0.0 hr)
		 5:     12800 ms (0.0 hr)
		 6:     25600 ms (0.01 hr)
		 7:     51200 ms (0.01 hr)
		 8:    102400 ms (0.03 hr)
		 9:    204800 ms (0.06 hr)
		10:    409600 ms (0.11 hr)
		11:    819200 ms (0.23 hr)
		12:   1638400 ms (0.46 hr)
		13:   3276800 ms (0.91 hr)
		14:   6553600 ms (1.82 hr)
		15:  13107200 ms (3.64 hr)
		16:  26214400 ms (7.28 hr)
		17:  52428800 ms (14.56 hr)
		18: 104857600 ms (29.13 hr)
		19: 209715200 ms (58.25 hr)
		20: 419430400 ms (116.51 hr)
    */

	public static void schedule(Context context, PendingIntent intent, int count)
	{
		if (count <= MAX_RETRIES)
		{
			AlarmManager alarmManager = (AlarmManager) context.getSystemService(Context.ALARM_SERVICE);
			long multiplier = 1L << count;
			long timeFromNow = multiplier * INITIAL_RETRY_TIME;
			long retryAt = SystemClock.elapsedRealtime() + timeFromNow;
			Log.d(TAG, "Scheduling a retry in " + timeFromNow + " ms from now");
			alarmManager.set(AlarmManager.RTC, retryAt, intent);
		} else
		{
			Log.d(TAG, "Too many retries, no more.");
		}
	}
}