Develop Reference

How to change repeating interval of AlarmManager at runtime in Android

I have written the following AlarmManager to start a Service which will download a file at specified interval:
Calendar updateTime = Calendar.getInstance();
updateTime.setTimeZone(TimeZone.getDefault());
updateTime.set(Calendar.HOUR_OF_DAY, 7);
Intent downloader = new Intent(mActivity, FileDownloadService.class);
downloader.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
PendingIntent pendingIntent = PendingIntent.getBroadcast(mActivity, 0, downloader, PendingIntent.FLAG_UPDATE_CURRENT);
AlarmManager alarmManager = (AlarmManager)getSystemService(Context.ALARM_SERVICE);
alarmManager.setRepeating(AlarmManager.RTC_WAKEUP, updateTime.getTimeInMillis(), AlarmManager.INTERVAL_DAY, pendingIntent);
From the other part of the application, I get the value for repeating interval to run the Service. The value for repeating interval change on daily basis.
How can we change the AlarmManager interval at runtime as the above code will be executed only once?
For example, on day 1 I want the repeating interval to be 15 minutes and on day 2 I want the interval to be 2 hours.
How can I change the repeating interval dynamically?

Store the value 15 minutes inside your pending intent as an extra. When your code gets triggered by the alarm manager, get the current value, increment it as per your needs and reset the extra in the intent which holds the value.
Edit : Use alarmManager.set(int type, long triggerAtMillis, PendingIntent operation); at every new invocation of your code.

Android daily repeating notification at specific time of a day using AlarmManager

I need to the Android app to send notification to remind users at 8am, 3pm and 8pm every day. So I use the following three lines in onCreate() of the MainActivity, when the application starts. However, when I run the app, all three notification are coming at once instead of at the wanted time.
setRepeatedNotification(1,8,0,0);
setRepeatedNotification(2,15,0,0);
setRepeatedNotification(3,20,0,0);
Why is that? I also attach the setRepeatedNotification function here. Thank you!
private void setRepeatedNotification(int ID, int hh, int mm, int ss) {
AlarmManager alarmManager = (AlarmManager) getSystemService(ALARM_SERVICE);
Intent alarmIntent = new Intent(MainActivity.this, AlarmReceiver.class);
PendingIntent pendingIntent = PendingIntent.getBroadcast(MainActivity.this, ID, alarmIntent, 0);
Calendar calendar = Calendar.getInstance();
// calendar.set();
calendar.set(Calendar.HOUR_OF_DAY, hh);
calendar.set(Calendar.MINUTE, mm);
calendar.set(Calendar.SECOND, ss);
// Clear previous everyday pending intent if exists.
if (null != mEverydayPendingIntent) {
alarmManager.cancel(mEverydayPendingIntent);
}
mEverydayPendingIntent = pendingIntent;
alarmManager.setRepeating(AlarmManager.RTC, calendar.getTimeInMillis(), AlarmManager.INTERVAL_DAY, mEverydayPendingIntent);
}

Here is the updated code:
private void setRepeatedNotification(int ID, int hh, int mm, int ss) {
AlarmManager alarmManager = (AlarmManager) getSystemService(ALARM_SERVICE);
Intent alarmIntent = new Intent(StartActivity.this, AlarmReceiver.class);
alarmIntent.putExtra("ID",ID);
Log.d("setRepeatedNotification", "ID:" + ID);
PendingIntent pendingIntent = PendingIntent.getBroadcast(StartActivity.this, ID, alarmIntent, PendingIntent.FLAG_UPDATE_CURRENT);
Calendar calendar = Calendar.getInstance();
Calendar now = Calendar.getInstance();
calendar.set(Calendar.HOUR_OF_DAY, hh);
calendar.set(Calendar.MINUTE, mm);
calendar.set(Calendar.SECOND, ss);
//check whether the time is earlier than current time. If so, set it to tomorrow. Otherwise, all alarms for earlier time will fire
if(calendar.before(now)){
calendar.add(Calendar.DATE, 1);
}
mEverydayPendingIntent = pendingIntent;
alarmManager.setRepeating(AlarmManager.RTC_WAKEUP, calendar.getTimeInMillis(), AlarmManager.INTERVAL_DAY, mEverydayPendingIntent);
}

I see two potential problems with your setup with AlarmManager. The first arises when the device goes to sleep.
From AlarmManager's documentation:
If an alarm is delayed (by system sleep, for example, for non _WAKEUP alarm types), a skipped repeat will be delivered as soon as possible. After that, future alarms will be delivered according to the original schedule; they do not drift over time. For example, if you have set a recurring alarm for the top of every hour but the phone was asleep from 7:45 until 8:45, an alarm will be sent as soon as the phone awakens, then the next alarm will be sent at 9:00.
As you can see, if you've set an alarm and the device has gone to sleep, without using AlarmManager.RTC_WAKEUP there could be a long delay depending on how long the device has been in sleep for. If you've never touched your device and no other alarms caused a wakeup, it could cause all your alarms to stack up upon the next hour that the device is awake for.
Another potential issue I see is that you are retrieving a Calendar instance representing the time right now, but then setting the hour, minute and second by yourself. The current day and the current year have been automatically populated from the current time.
Again, from the documentation (emphasis mine):
If the stated trigger time is in the past, the alarm will be triggered immediately, with an alarm count depending on how far in the past the trigger time is relative to the repeat interval.
In this case, if your method was invoked past 8 pm on the given day, calendar.getTimeInMillis() will return a timestamp in the past for all three alarms, causing them to be triggered immediately since 8 am, 3 pm and 8 pm have already past in that day. In this case, you must first evaluate whether the current time is past the alarm interval you are trying to set and add 1 day more onto the time you are setting to make sure the alarm has been set in the future.

Stop a service at specific time

I am starting my service using below code repeatedly. My service starts at 8am everyday. And AlarmManager repeates at every 1 min. I want to stop this sevice at 6pm. how can I do this ?
AlarmManager manager = (AlarmManager) getSystemService(Context.ALARM_SERVICE);
PendingIntent loggerIntent = PendingIntent.getBroadcast(this, 0,new Intent(this,AlarmReceiver.class), 0);
Calendar timeOff9 = Calendar.getInstance();
timeOff9.set(Calendar.HOUR_OF_DAY, 08);
timeOff9.set(Calendar.MINUTE, 00);
timeOff9.set(Calendar.SECOND, 00);
//--------------------------------------------------------------------------------------------------------------------
long duration = userinterval * 60 * 1000;
manager.setRepeating(AlarmManager.RTC_WAKEUP,timeOff9.getTimeInMillis(), duration, loggerIntent);

In order to cancel at 6pm exactly, I would consider 2 options:
Each time the alarm triggers (i.e. every 1 minute), check the time, and cancel if time is after 6PM.
Set a once-off alarm in AlarmManager to go off at 6PM exactly. In that alarm, cancel.
I prefer option 2 for simplicity, and modularity of each code block. So for me, I would use (2) in my proof-of-concept code, while working on the solution.
But option 1 is better from a resources point of view, as the Android system only needs to remember a single alarm. I would use (1) in my final production code.
This way of working is just my personal preference, and most ppl probably will say to use (1) right away from the start.
The details about cancelling are below...
As for how to cancel an alarm, you don't often beat an answer by #commonsware....
Below answer copied from How to cancel this repeating alarm?
Call cancel() on AlarmManager with an equivalent PendingIntent to the one you used with setRepeating():
Intent intent = new Intent(this, AlarmReceive.class);
PendingIntent sender = PendingIntent.getBroadcast(this,
0, intent, 0);
AlarmManager alarmManager = (AlarmManager) getSystemService(ALARM_SERVICE);
alarmManager.cancel(sender);

How to stop repeating alarm at specific time

I am starting my alarm at 8am using below code, repeating at every 1min. I want to stop this alarm repeating at 12pm. I am starting alarm like this:
AlarmManager manager = (AlarmManager) getSystemService(Context.ALARM_SERVICE);
PendingIntent loggerIntent1 = PendingIntent.getBroadcast(this, 0,new Intent(this,AlarmReceiver.class), 0);
Calendar timeOff9 = Calendar.getInstance();
timeOff9.set(Calendar.HOUR_OF_DAY, 08);
timeOff9.set(Calendar.MINUTE, 00);
timeOff9.set(Calendar.SECOND, 00);
long duration = interval * 60 * 1000;
manager.setRepeating(AlarmManager.RTC_WAKEUP,timeOff9.getTimeInMillis(), duration, loggerIntent1);
and stopping with this code:
Calendar timeOff = Calendar.getInstance();
timeOff.set(Calendar.HOUR_OF_DAY,12);
timeOff.set(Calendar.MINUTE,00);
timeOff.set(Calendar.SECOND, 00);
manager.set(AlarmManager.RTC_WAKEUP,timeOff.getTimeInMillis(), loggerIntent1);
manager.cancel(loggerIntent1);
loggerIntent1.cancel();
but the code for stopping causes the app to work the wrong way.
I am writing the code to stop alarm right after first alarm. is it the problem?
Do I need to write another alarm. Please guide.

Maybe there is another logic you could give a try?
Imagine this, carry on with your first portion of code where you trigger an intent for every duration.
But inside your AlarmReceiver.class, that will be the one checking current time, and do the AlarmManager.cancel() when the time is over 12pm.

How to call receiver one a hour?

Is it possible to call receiver only on start of every new hour? I have running service and I need to call receiver only when the time changes from for example: five o'clock to six o'clock, etc.? Is there any way how can I do it?

You will need to use an AlarmManager. Then schedule the times you want it to notify you. Google for more examples.
UPDATE:
What you can do is wake it up at the next hour, at 8.00 if time is 7.30 . Then shedule it for an hourly wake up the next time it starts.
Calendar c = Calendar.getInstance();
c.set(Calendar.HOUR,c.get(Calendar.HOUR)+1);
c.getTimeInMillis(); // use this in alarmmanager for the first time, 60*60*1000 from next time

You can use a combination of GregorianCalendar and an AlarmManager for this. You basically add 1 hour to the current time and then round downwards to the nearest hour. See an example here:
long UPDATE_INTERVAL = 60 * 60 * 1000; // 1 hour in milliseconds.
Calendar c = new GregorianCalendar(); // Get current time
c.add(Calendar.HOUR_OF_DAY, 1); // Add one hour to the current time.
// Set minutes, second, millisecond to 0, such that we ensure that an update is done
// at the end of the hour.
c.set(Calendar.MINUTE, 0);
c.set(Calendar.SECOND, 0);
c.set(Calendar.MILLISECOND, 0);
final AlarmManager alarm = (AlarmManager) context.getSystemService(ALARM_SERVICE);
// Set an alarm, starting from the end of the current hour, every hour, to execute
// the update service.
// pIntent is the pending intent you would like activate.
alarm.setRepeating(AlarmManager.RTC, c.getTimeInMillis(), UPDATE_INTERVAL, pIntent);
I assume you know how to call the receiver.