I am attempting to create a sample alarm application using AlarmManager. However, the alarm goes off at different times even though I have set a specific time for it to be triggered.
Setting the alarm:
Calendar calendar = Calendar.getInstance();
calendar.setTimeInMillis(System.currentTimeMillis());
calendar.set(Calendar.HOUR_OF_DAY, 18); // trigger at 6 PM
Intent notifyIntent = new Intent(context, CheckupAlarmReceiver.class);
PendingIntent pendingIntent = PendingIntent.getBroadcast
(context, 100, notifyIntent, PendingIntent.FLAG_UPDATE_CURRENT);
android.app.AlarmManager alarmManager = (android.app.AlarmManager) context.getSystemService(Context.ALARM_SERVICE);
if (alarmManager != null) {
alarmManager.setInexactRepeating(android.app.AlarmManager.RTC_WAKEUP, calendar.getTimeInMillis(),
android.app.AlarmManager.INTERVAL_DAY, pendingIntent);
}
Manifest:
<receiver
android:name=".notifications.CheckupAlarmReceiver"
android:enabled="true"
android:exported="false" />
To re-iterate, the alarm works fine. It just fires at the wrong time. Is the Calendar instance not taking the time zone in to consideration? What am I doing wrong here?
Your are setting setInexactRepeating() which as its name says, it could not be fired at the exact time you specified. This is an optimization so the Operating System tries to get more than one alarm which should fire at similar times to fire all of them at the same time.
Instead, you can use void setExactAndAllowWhileIdle(int type, long triggerAtMillis, PendingIntent operation). See documentation.
Example:
alarmManager.setExactAndAllowWhileIdle(android.app.AlarmManager.RTC_WAKEUP, calendar.getTimeInMillis(), pendingIntent);
As its recommended, you shouldn't use a repeating alarm with exact times. Instead, you can wait until the exact alarm fires and then schedule another alarm for the next day.
For API lower than 23, you can use void setExact(int type, long triggerAtMillis, PendingIntent operation). And for API lower than 19, you can use void setRepeating(int type, long triggerAtMillis, long intervalMillis, PendingIntent operation) with the expected exact firing as always.
Related
I want to trigger a daily alarm in my application. I can see the alarm being triggered daily at the correct time for 2 or 3 days but it does not trigger after that. For example if I set alarm to trigger at 08:00 AM, it will trigger at 8 AM daily for 2 or 3 days and after that there is no alarm triggered. There is no app crashing or anything, it simply does not trigger. I have a BroadcastReceiver registered (in AndroidManifest.xml) for this alarm and i can see logs being printed daily at the correct time but only for 2 or 3 days. After that there is no activity and the app just seems to die down.
Please find my code below :
final AlarmManager alarmManager = (AlarmManager) context.getSystemService(Context.ALARM_SERVICE);
final long intervalDay = 60*60*24*1000L;
final long alarmTime = calendar.getTimeInMillis();
alarmManager.setRepeating(AlarmManager.RTC_WAKEUP, alarmTime, intervalDay, pendingIntent);
I have also used alarmManager.setRepeating(AlarmManager.RTC_WAKEUP, alarmTime, AlarmManager.INTERVAL_DAY, pendingIntent); but it did not make any difference (didnt expect it to make any though).
I do not want to use alarmManager.setInexactRepeating() as it does not trigger the alarm at exact time but there is slight delay.
Any help appreciated !!
Thanks.
That's because android cannot hold the alarm content for more than 2-3 days. Though there is no sure shot solution that i know.
I fixed it by cancelling and resetting alarm everytime alarm is triggered.
Something like this.
Instead of using setRepeat use set or setExact to trigger for once:
if(android.os.Build.VERSION.SDK_INT<Build.VERSION_CODES.KITKAT) {
alarmManager.set(AlarmManager.RTC_WAKEUP, alarmtime, pendingIntent);
} else {
alarmManager.setExact(AlarmManager.RTC_WAKEUP, alarmtime, pendingIntent);
}
Then in onRecieve() method of your alarmReciever after performing your task, reset the alarm again for next followed by cancelling all pending intents:
PendingIntent pendingIntent = PendingIntent.getBroadcast(context.getApplicationContext(), reminderModal.get_remindID(), intent, PendingIntent.FLAG_UPDATE_CURRENT);
AlarmManager alarmManager = (AlarmManager) context.getApplicationContext().getSystemService(Context.ALARM_SERVICE);
alarmManager.cancel(pendingIntent);
pendingIntent.cancel();
Hope it helps.
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.
I have one problem I need to set AlarmReceiver.
I am using this code for it:
Calendar cal = Calendar.getInstance();
cal.set(Calendar.SECOND, cal.get(Calendar.SECOND) + 5);
AlarmManager alarm = (AlarmManager)getActivity().getSystemService(Context.ALARM_SERVICE);
Intent i = new Intent(getActivity(), AlarmReceiver.class);
PendingIntent pIntent = PendingIntent.getBroadcast(getActivity(), 0, i, 0);
alarm.setRepeating(AlarmManager.RTC_WAKEUP, cal.getTimeInMillis(), 1000*5, pIntent);
So it means that this AlarmManager will call AlarmReceiver every 5 seconds, but problem is that if I don't turn my screen OFF manually, screen will stay ON and this is not what I want.
From the AlarmManager reference documents:
The parameter AlarmManager.RTC_WAKEUP, will wake up the device (in case of device sleep) to deliver the Alarm. You may use AlarmManager.RTC but that won't be wake up the device and your Alarm won't be delivered until next time device wakes up.
A better option would be to use a Service for this purpose, as they are designed to carry out the background tasks.
I have an alarm which I can schedule to go off at a certain time. The thing is, when I shedule it into the future, it works at exactly the minute I set it for. It works as it should. But the problem is, if I schedule it in the past, it goes off immediately.
For example, if it is now 3:30pm and I schedule it for 3:35pm, it fires at 3:35pm. But if it is 3:30pm and I schedule it for 3:25pm, it fires immediately since it is in the past.
What I want it to do is, if it is int he past, just ignore it until the interval time passes.
Here is the code:
Intent intent = new Intent(context, AlarmReceiver.class);
PendingIntent sender = PendingIntent.getBroadcast(context, ApplicationClass.AlertNotifyID, intent, PendingIntent.FLAG_UPDATE_CURRENT);
AlarmManager am = (AlarmManager) context.getSystemService(Context.ALARM_SERVICE);
long milliSeconds24Hours = 86400000; //86400000 which is 24 hours in milliseconds
am.setRepeating(AlarmManager.RTC_WAKEUP, GetNotificationTime(context), milliSeconds24Hours, sender);
You need to get it to check if the scheduled time is in the past, and if so set your alarm to start the next day.
I am trying to use this to set an alarm that goes off everyday.
String alarm = Context.ALARM_SERVICE;
Calendar calendar = Calendar.getInstance();
AlarmManager am = (AlarmManager)getActivity().getSystemService(alarm);
Intent intent = new Intent("NEW_ITEM");
PendingIntent sender = PendingIntent.getBroadcast(getActivity(), 0, intent, 0);
calendar.setTimeInMillis(System.currentTimeMillis());
am.setRepeating(AlarmManager.RTC_WAKEUP, calendar.getTimeInMillis(), 1*AlarmManager.INTERVAL_DAY, sender);
Without running it, the code looks good to me... Obviously, if you set this alarm every time you start the activity, the alarm will go off immediately since: am.setRepeating(AlarmManager.RTC_WAKEUP, **calendar.getTimeInMillis()**, 1*AlarmManager.INTERVAL_DAY, sender); Tells the alarm manager to alert right now (2nd param) and to repeat in a day (3rd param, assuming your constant is correct).
If you want the alert to start only in 24 hours, simply change the line to:
am.setRepeating(AlarmManager.RTC_WAKEUP, System.currentTimeMillis() + AlarmManager.INTERVAL_DAY, AlarmManager.INTERVAL_DAY, sender);
Code looks good, but you have to be aware of one thing. If the user decides to set the alarm again (for example, by hitting the 'set the alarm' button) the old one will be replaced. If you want to avoid this, check out this topic: Using Alarmmanager to start a service at specific time