Develop Reference

dynamic alarm manager at midnight

my mean goal is to run a task periodically at midnight (00:00:00)
but the user can set the period based on the interval (daily, weekly , monthly)
let's assume that this job is a backup Scheduling.
this task will triggred at midnight but based on the user preference (midnight everyday, every week , or monthly ), and if the phone was in the doze mode or even off , wait untill the next start and start backup.
when i start implementing the code , i started with JobService and JobScheduler , but unfortunately i learned that i can set the repetitive but i can't set the exact time, so the last solution was to work with alarmmanager.
i use this code for triggering the alarm :
public static void setTheTimeToStartBackup(Context context,String periode) {
int DATA_FETCHER_RC = 123;
AlarmManager mAlarmManager = (AlarmManager)context.getSystemService(Context.ALARM_SERVICE);
Calendar calendar = Calendar.getInstance();
Intent intent = new Intent(context, BackUpAlarmRecevier.class);
PendingIntent pendingIntent = PendingIntent.getBroadcast(context, DATA_FETCHER_RC,intent, PendingIntent.FLAG_UPDATE_CURRENT);
long interval = 0;
switch (periode){
case "never":
return;
case "daily":
alarmStartTime.set(Calendar.HOUR_OF_DAY, 0);
interval = AlarmManager.INTERVAL_DAY;
break;
case "weekly":
alarmStartTime.set(Calendar.DAY_OF_WEEK, 1);
interval = AlarmManager.INTERVAL_DAY*7;
break;
case "monthly":
alarmStartTime.set(Calendar.WEEK_OF_MONTH, 1);
interval = AlarmManager.INTERVAL_DAY*30;
break;
}
alarmStartTime.set(Calendar.HOUR_OF_DAY, 0);
alarmStartTime.set(Calendar.MINUTE, 0);
alarmStartTime.set(Calendar.SECOND, 0);
mAlarmManager.setRepeating(AlarmManager.RTC_WAKEUP,calendar.getTimeInMillis(),interval, pendingIntent);
Log.e("Alarm","Set for midnight");
}
this is my receiver :
public class BackUpAlarmRecevier extends BroadcastReceiver {
SharedPreferences preferences;
#Override
public void onReceive(Context context, Intent intent) {
Log.e("BackUpAlarmReciver","Triggred");
PowerManager pm = (PowerManager) context.getSystemService(Context.POWER_SERVICE);
PowerManager.WakeLock wl = pm.newWakeLock(PowerManager.PARTIAL_WAKE_LOCK, "TAG:APP");
wl.acquire();
sendNotification(context);// simple notification...
Toast.makeText(context, "Alarm !!", Toast.LENGTH_LONG).show();
startBackupProcess();
wl.release();
}}
the problem is task never start.
so i went to test it with less time interval (15min as the minimum possible as i read ), so i change my first function setTheTimeToStartBackup to this :
public static void setTheTimeToStartBackup(Context context,String periode) {
int DATA_FETCHER_RC = 123;
AlarmManager mAlarmManager = (AlarmManager)context.getSystemService(Context.ALARM_SERVICE);
Calendar calendar = Calendar.getInstance();
calendar.set(Calendar.SECOND, 55);
Intent intent = new Intent(context, BackUpAlarmRecevier.class);
PendingIntent pendingIntent = PendingIntent.getBroadcast(context, DATA_FETCHER_RC,intent, PendingIntent.FLAG_UPDATE_CURRENT);
mAlarmManager.setRepeating(AlarmManager.RTC_WAKEUP,calendar.getTimeInMillis(),AlarmManager.INTERVAL_FIFTEEN_MINUTES, pendingIntent);
Log.e("Alarm","Set for midnight");
}
and exactly the same problem , nothing started, no log , no notification , nothing.
and i already set the Receiver in my manifest with all permission like that :
<receiver android:name=".job.BackUpAlarmRecevier"
android:enabled="true"
android:process=":remote"
android:exported="true">
<intent-filter>
<action android:name="android.intent.action.BOOT_COMPLETED" />
</intent-filter>
</receiver>
what im doing wrong in both cases ? and if it work , this code will persist for ever or i need to set it again each time ?
thanks :)
EDIT:
i call my function setTheTimeToStartBackup in the MainActivity.

You could set it to occur at midnight if you did the appropriate time calculations. Dynamically get the current time and date, calculate when to register the broadcast for the alarm manager. Customize the onReceive method to set another alarm at 12pm again.
Either way you can trigger a broadcast receiver by registering your receiver manually.
Broadcast receiver class:
public class AlarmReceiver extends BroadcastReceiver {
#Override
public void onReceive(Context context, Intent intent) {
System.out.println("Alarm received!! ");
// Register alarm again here.
}
}
Code to register a receiver with a custom intent filter.
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
AlarmManager mAlarmManager = (AlarmManager)getApplicationContext().getSystemService(Context.ALARM_SERVICE);
getApplicationContext().registerReceiver(new AlarmReceiver(), new IntentFilter("AlarmAction"));
PendingIntent broadcast = PendingIntent.getBroadcast(this, 0, new Intent("AlarmAction"), 0);
// Add dynamic time calculations. For testing just +100 milli.
mAlarmManager.set(AlarmManager.RTC_WAKEUP, System.currentTimeMillis() + 100, broadcast);
;
}
You could achieve what you wanted through a background service.

My suggestion would be to turn the problem around a bit.
Create three topics on Firebase (daily, weekly, monthly). Subscribe users to appropriate topics. Have a Firebase function that is triggered by CRON job which sends the data notification down to the device, this data notification should schedule one-time WorkManager job for the update. This way you can control everything from server-side, if the phone is off, it will still execute as soon as it turns on and you don't need to manually take care of catching the Boot completed with alarm manager etc.

Alarm Manager is sometimes very long to run the intent

I got a problem with the AlarmManager. When the alarm is set, if the alarm's hour has already passed the intent is started which is great. But sometimes there is a very long time (from 30 secondes to 3 minutes) before the intent is started. If anyone knows why, I'm curious to understand.
Here is my code :
public static void setAlarm()
{
Intent intent = new Intent(Application.Context, typeof(AlarmReceiver));
intent.SetAction("ExchangeGo");
PendingIntent pendingIntent = PendingIntent.GetBroadcast(Application.Context, 0, intent, PendingIntentFlags.CancelCurrent);
Calendar dayCalendar = Calendar.GetInstance(Java.Util.TimeZone.Default);
dayCalendar.Set(CalendarField.HourOfDay, 8);
dayCalendar.Set(CalendarField.Minute, 30);
dayCalendar.Set(CalendarField.Second, 0);
dayCalendar.Set(CalendarField.Millisecond, 0);
AlarmManager alarm = Application.Context.GetSystemService(Context.AlarmService).JavaCast<AlarmManager>();
alarm.Cancel(pendingIntent);
alarm.SetRepeating(AlarmType.RtcWakeup, dayCalendar.TimeInMillis, AlarmManager.IntervalDay, pendingIntent);
}
And here the intent :
[BroadcastReceiver]
public class AlarmReceiver : BroadcastReceiver
{
private String SOMEACTION = "ExchangeGo";
public override void OnReceive(Context context, Intent intent)
{
String action = intent.Action;
if (SOMEACTION.Equals(action))
{
Intent intentService = new Intent(context, typeof(ExchangeService2));
context.StartService(intentService);
}
}
}
There is no problem with manifest cause it works, just a bit too long sometimes. And the problem is not from my second intent because I put a breakPoint just before and the waiting time is before the break point.
Anyone ?
Thanks for reading me.

As setRepeating() doesn't guarantee that it will happen at precise time.
That's why you are getting delay of 30 secondes to 3 minutes.
Replace setRepeating() with setExact() refer documentation from Here
manager.setExact(AlarmManager.RTC, startTime.getTimeInMillis(), operation);
To repeat this what you can do is, to schedule this alarm again after executing your current event. So when your 1st intent gets executed schedule alarm for 2nd event using setExact() only. This will guarantee the time accuracy you are expecting

How to keep a service alive using AlarmManager.setInexactRepeating()?

I have some existing code that spawns a service intent which does a bunch of stuff in the background. This code does work...
Intent serviceIntent = new Intent(context, APMService.class);
serviceIntent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
context.startService(serviceIntent);
My question is: how to change this to use the AlarmManager.setInexactRepeating(...) methods?
I have changed the above code to this:
Intent serviceIntent = new Intent(context, APMService.class);
serviceIntent.putExtra("STARTED_BY", starter);
serviceIntent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
//Set up recurring alarm that restarts our service if
// it crashes or if it gets killed by the Android OS
AlarmManager am = (AlarmManager) context.getSystemService(Context.ALARM_SERVICE);
PendingIntent pi = PendingIntent.getService(context, 0, serviceIntent, 0);
//am.cancel(pi);
am.setInexactRepeating(
AlarmManager.ELAPSED_REALTIME_WAKEUP //wake up the phone if it's asleep
, cal.getTimeInMillis()
, 10000
, pi);
And I have added these permissions to AndroidManifest.xml...
<uses-permission android:name="com.android.alarm.permission.SET_ALARM"/>
<uses-permission android:name="com.android.alarm.permission.WAKE_LOCK"/>
My understanding is that this is supposed to start the service immediately and then try to restart it again every 10 seconds. But this code isn't working properly.
Using this new code, the service never starts at all and I cannot see why not. To complicate matters the debugger never seems to attach to the app in time to see what's going on.
Can anyone see what I'm doing wrong?

Put AlarmManager code under onDestroy() function of service to schedule start of service as below:
#Override
public void onDestroy() {
/**
* Flag to restart service if killed.
* This flag specify the time which is ued by
* alarm manager to fire action.
*/
final int TIME_TO_INVOKE = 5 * 1000; // try to re-start service in 5 seconds.
// get alarm manager
AlarmManager alarms = (AlarmManager) context.getSystemService(Context.ALARM_SERVICE);
Intent intent = new Intent(context, AutoStartServiceReceiver.class);
PendingIntent pendingIntent = PendingIntent
.getBroadcast(context, 0, intent, PendingIntent.FLAG_CANCEL_CURRENT);
// set repeating alarm.
alarms.setRepeating(AlarmManager.RTC_WAKEUP, System.currentTimeMillis() +
TIME_TO_INVOKE, TIME_TO_INVOKE, pendingIntent);
}
And handle starting of your service in AutoStartServiceReceiver as below:
public class AutoStartServiceReceiver extends BroadcastReceiver {
private static final String TAG = AutoStartServiceReceiver.class.getSimpleName();
#Override
public void onReceive(Context context, Intent intent) {
// check broadcast action whether action was
// boot completed or it was alarm action.
if (intent.getAction().equals(AppConstants.ACTION_ALARM_INTENT)) {
context.startActivity(new Intent(context, YourActivity.class));
// handle service restart event
LockerServiceHelper.handleServiceRestart(context);
}
}
}
Kindly note that, your service will not restart if you stop it manually from settings-apps-running apps-your app.

Your service is not starting because of AlarmManager.ELAPSED_REALTIME_WAKEUP, while it should be using AlarmManager.RTC_WAKEUP
If you want to run every 10s keep in mind that above API 21 alarm intervals below 60s are rounded up to 60s.
Also, consider using WakefulIntentService
https://github.com/commonsguy/cwac-wakeful

Alarm "onReceive" not being called

I'm trying to create an Alarm that will fix lost connections to Google Cloud Messaging that occur due to the heartbeat bug, found here How to avoid delay in Android GCM messages / change heartbeat
However, my alarm's onReceive class which I have being set to be called every 1 minute for testing is never being called. I've looked in several of the other questions pertaining to this topic, and all of them concentrate on spelling and declaring the receiver in the manifest, which I've checked several times.
Here is all the relevant code:
MainActivity.java
//Alarm created here
GCMHeartbeatAlarm gcmAlarm = new GCMHeartbeatAlarm();
gcmAlarm.setAlarm(this);
GCMHeartbeatAlarm.java
public class GCMHeartbeatAlarm extends BroadcastReceiver {
private AlarmManager alarmMgr;
private PendingIntent alarmIntent;
#Override
public void onReceive(Context context, Intent intent) {
//The part which is supposedly going to fix the GCM connection dropped bug, needs to be called every 5 mins or so via alarm to keep
//GCM connection open
//Commented out for now
// context.sendBroadcast(new Intent("com.google.android.intent.action.GTALK_HEARTBEAT"));
// context.sendBroadcast(new Intent("com.google.android.intent.action.MCS_HEARTBEAT"));
Log.i("GCMHeartbeat", "GCM Heartbeat Sent!");
}
public void setAlarm(Context context) {
alarmMgr=(AlarmManager)context.getSystemService(Context.ALARM_SERVICE);
Intent intent = new Intent(context, GCMHeartbeatAlarm.class);
alarmIntent = PendingIntent.getBroadcast(context, 0, intent, 0);
//Repeat every 1 minute
alarmMgr.setRepeating(AlarmManager.ELAPSED_REALTIME, System.currentTimeMillis(), 1000 * 60 * 1 , alarmIntent);
Log.i("GCMHeartbeat", "Alarm set!");
}
}
AndroidManifest.xml
<!-- GCM Heartbeat Alarm Receiver -->
<receiver
android:name="com.MyApp.app.GCMHeartbeatAlarm">
</receiver>
With this code, the "Alarm Set!" log is hit, but the log in onReceive is never hit.
Anything that could help me figure out what's going on would be greatly appreciated!

Got it to work eventually. I'm not quite sure why, but using System.currentTimeMillis() wasn't working for the triggerAtMillis value. Perhaps it was because the alarm was set for ELAPSED_REALTIME instead of currentTimeMillis(), so the first alarm was never triggered. Instead I used SystemClock.elapsedRealtime() + 60 * 1000 to trigger the alarm beginning 1 minute after it is set, and then the onReceive method started being called in 1 minute intervals.
The working code was:
public void setAlarm(Context context) {
alarmMgr = (AlarmManager)context.getSystemService(Context.ALARM_SERVICE);
Intent intent = new Intent(context, GCMHeartbeatAlarm.class);
alarmIntent = PendingIntent.getBroadcast(context, 0, intent, 0);
alarmMgr.setRepeating(AlarmManager.ELAPSED_REALTIME, SystemClock.elapsedRealtime() + 60 * 1000, 60 * 1000, alarmIntent);
Log.e("GCMHeartbeat", "Alarm set!");
}

Android AlarmService repeating alarm repeats once more after cancel is called

First off,this site is great and everyone is so helpfull. This is my first post so forgive me if i have ommited anything.
I create an alarm like so:
private void startLocation() {
AlarmManager alarm = (AlarmManager) context.getSystemService(Context.ALARM_SERVICE);
Intent i = new Intent(context, MyWeatherUpdateService.class);
PendingIntent service = PendingIntent.getService(context, 0, i,
PendingIntent.FLAG_CANCEL_CURRENT);
alarm.setRepeating(AlarmManager.RTC, SystemClock.elapsedRealtime() + (60 * 1000),
Long.parseLong(prefs.getString("listpref", "60000")), service);
}
In this method which is called inside a fragment, context is from getApplication (), listpref is a string update interval in milliseconds.
I cancel it by:
public void endLocation() {
Intent i = new Intent(context, MyWeatherUpdateService.class);
PendingIntent service = PendingIntent.getService(context, 0, i,
PendingIntent.FLAG_CANCEL_CURRENT);
alarm.cancel(service);
}
Ensuring that the intent/pending intent is the same.
Now i have 2 issues:
1) the alarm fires almost imediately after creation, even though i tell it to start after 1min.
2) when i call cancel, the alarm fires once more before the alarm is cancelled.
With question 1) why does the alarm fire so soon? And with 2) is this working as intended or should the alarm cancel immediately like i want it to.
If i have not supplied enough info, ill add more code if required.
Thanks in advance.

the alarm fires almost imediately after creation, even though i tell it to start after 1min
That is because you are using RTC with an elapsedRealtime() starting time. Those need to match. The simplest solution is to switch to ELAPSED_REALTIME.
when i call cancel, the alarm fires once more before the alarm is cancelled.
Try replacing PendingIntent.FLAG_CANCEL_CURRENT with 0, at least in the PendingIntent for your cancel() call.