In my project, I have a database with Year, Month, Day, Hour, Minute. For each row in this database I want to put notification with Title and description for user in time, that described in that row, but when I use NotificationManager, it activates at once when I add new time to database. I read this article: Alarm Manager Example, about Alarm Manager Example, but I still can't understand, how to use it for notifications, because when I try to use, nothing happens. I'll be glad, if someone can help me.
Your message isn't clear to me. If you are trying to launch notifications at a certain time, this is one way to do it. Use 2 services; one service (you could call it SetAlarmService) to read your DB and set a pending intent to launch at a certain time with the AlarmManager. You can get an instance by calling getSystemService(Context.ALARM_SERVICE);. You should set your pending intent to launch another service (you could call it NotifyService), which will simply put up the notification as soon as it is started.
EDIT: here is a quick example, see the documentation for explanations of parameters, etc.
public class AlarmService extends Service {
Time time;
AlarmManager alarmMan;
#Override
public void onCreate() {
alarmMan = (AlarmManager) getSystemService(Context.ALARM_SERVICE);
time = new Time();
}
#Override
public int onStartCommand(Intent intent, int startID, int flags) {
time.setToNow();
alarmMan.set(AlarmManager.RTC_WAKEUP, time.toMillis(false)+(10*1000), getPIntent());
time = null;
}
public PendingIntent getPIntent() {
Intent startIntent = new Intent(this, NotifyService.class);
startIntent.setAction(com.berrmal.remindme.NotifyService.ACTION_SEND_NOTIFICATION);
PendingIntent pIntent = PendingIntent.getService(this, 0, startIntent, PendingIntent.FLAG_CANCEL_CURRENT);
return pIntent;
}
I launch this service from an activity, you can do it any way you want. NotifyService.class is another service I have written that just immediately posts a sticky notification, I'm not going to show that because it sounds like you already know how to use the NotificationManager. The key here is the 10*1000, that is how many milliseconds in the future the alarm will be activated, and thus what time the notification will show up. You could read that from a file, etc. In this example, I am just calculating 10000 millis in the future from now. The RTC_WAKEUP flag is one of 4 flags that you will want to read about, they make the alarm do slightly different things. Hope that helps.
Related
In my app i am using AlarmManagerto start service every week on a specific time. But in some cases instead of waiting another 7 days I need to call the service on the next day. Because of that I'm not using reapeating alarm but instead in the started service I'm creating new Alarm and set it to a specific date. Something like this:
public class AlarmService extends Service {
#Override
public int onStartCommand(Intent intent, int flags, int startId) {
//do something
//setting new alarm
AlarmManager alarmMng = (AlarmManager)getSystemService(Context.ALARM_SERVICE);
Intent i = new Intent(this,AlarmService.class);
PendingIntent alarmIntent = PendingIntent.getService(this, 0, i, 0);
Calendar c = Calendar.getInstance();
if(something) alarmMng.set(AlarmManager.RTC_WAKEUP, c.getTimeInMillis()+1000*60*60*24,alarmIntent);
else alarmMng.set(AlarmManager.RTC_WAKEUP, c.getTimeInMillis()+1000*60*60*24*7,alarmIntent);
return START_STICKY;
}
#Nullable
#Override
public IBinder onBind(Intent intent) {
return null;
}
Everything works fine but I wonder if this is good way to do it. Is it a good idea to create new alarm from service that was just called by one? Is it considered bad programming practice? If so how else should I handle it?
Is it considered bad programming practice?
No - this is a fine use case for creating alarm events. If you look at the documentation, use of AlarmManager is intended to send events to your app even if it is not running. Receiving those events in a Service that then schedules another alarm event is perfectly fine. The rest of my answer is intended to explain how to answer the other question you ask:
Is it a good idea to create new alarm from service that was just
called by one?
To determine if you need a Service really depends on the "do something" portion of your code more than setting the alarm. For example, you might be fine using a IntentService or even a BroadcastReceiver.
EDIT:
In other words, you will need a background process to handle this. Determining the appropriate background process (Receiver or Service) depends on how much processing needs to be done. Generally, setting an alarm all by itself could probably be handled in a Receiver but if it takes too long to process (e.g. more than 10 seconds) you will get an ANR (Application Not Responding) crash. That's when you need a service.
END EDIT..
This is a good post about services: Service vs IntentService
Specifically, the concern you should have is if your service is called multiple times, you should probably include code to cancel any previous alarms created by it, before setting a new alarm.
EDIT: Also, you are not "creating a new service" or "new alarm" each time. Services will have onStartCommand called each time an intent is sent to it (by the AlarmManager or by any other means). A new instance is not created unless it is not already instantiated.
I'm trying to create a function in my App, which notifies the user at the expiration day of his rented books. I'll work with checkboxes in a listview, as below:
(Dates are for show purposes only)
Now i'm wondering how can i do it the best way. I'm having experiences with AlarmManager and BroadcastReceivers, but I didn't get a clear flowchart yet.
Thats because I need to set an specific alarm to each book and cancel that specific alarm when requested. Also, it needs to reactivate all Alarms when device is restared (by calling BOOT_COMPLETE broadcast).
PS.: Alarms will usually be set to one week after current date.
PS2.: Can I use Calendar to do it? I mean, this way i wouldn't have to reactivate all alarms, or calculate (expirationDate - currentDate) in millis.
Can someone, who has an idea, try to show me the way? Thanks!
I think the key would be to give each and every book its own alarm id as soon as you set the alarm for this book for the first time.
Then you should keep a list of the running alarm ids and timestamps (maybe in SharedPreferences).
With a method like this you can cancel a specific alarm with regards to its alarm id:
public static void cancelAlarm(Context context, int alarmId) {
PendingIntent pi = PendingIntent.getService(context, alarmId,
new Intent(context, YourService.class),
PendingIntent.FLAG_NO_CREATE);
if(pi!=null) {
AlarmManager am = (AlarmManager) context.getSystemService(Context.ALARM_SERVICE);
am.cancel(pi);
}
}
When you receive the BOOT broadcast, you can get the list of alarm ids together with timestamps from SharedPreferences and start all the alarms with their respective alarm ids
I've set a repeating alarm on a service and decided that it's most convenient to reset the alarm from within the called service. The reason is that the service already has code to check if it's within a user-defined schedule (time range). When it's outside the time range, it resets the alarm to start at the future time selected by the user. Maybe I'm approaching this wrong but I'll put this question out there and see what you think.
An activity kicks off the service by creating a repeating alarm:
//Activity
Calendar cal = Calendar.getInstance();
Intent intent = new Intent(getApplicationContext(), MyService.class);
intent.setData(Uri.parse("MyService://identifier"));
PendingIntent pIntent = PendingIntent.getService(getApplicationContext(), 0, intent, 0);
AlarmManager alarm = (AlarmManager)getSystemService(ALARM_SERVICE);
alarm.setInexactRepeating(AlarmManager.RTC_WAKEUP, cal.getTimeInMillis(),
intervalInMins*60000, pIntent);
The service has something like this:
//Service
#Override
public int onStartCommand(Intent intent, int flags, int startId) {
Uri Action = intent.getData();
try {
if (Action.equals(Uri.parse("MyService://identifier"))) {
//Simplifying the code here: CalculatedOffset is determined from the current time
//and scheduled start time. intervalInMins is read from settings.
if (!WithinSchedule()) {
Calendar cal = Calendar.getInstance();
PendingIntent pIntent = PendingIntent.getService(getApplicationContext(), 0, intent, 0);
AlarmManager alarm = (AlarmManager)getSystemService(ALARM_SERVICE);
alarm.setInexactRepeating(AlarmManager.RTC_WAKEUP, cal.getTimeInMillis() + CalculatedOffset,
intervalInMins*60000, pIntent);
}
}
} catch (NullPointerException np) {
np.printStackTrace();
}
return Service.START_REDELIVER_INTENT;
}
I was hoping to re-use the intent to reset the repeating alarm. With this new code, I'm seeing multiple alarms stack up firing rapidly in succession around when the start time hits. It should not spaz out like that, but should fire at regular intervals as it did before the scheduling reset. I need to catch it in the debugger but haven't been able to determine the exact conditions yet. Is my understanding of alarms completely off base here? Is there a better way to do this?
Addendum: A wrinkle in this is that I'm using RootTools to gain superuser privileges in order to work around Android 4.2's airplane mode. This hasn't been a problem before the scheduling, but I'm suspicious whether su is blocking for a long time while the alarms stack up.
Re-using the intent inside the service that receives the alarm does work. I've switched from using a Repeating Alarm to a single-shot alarm which gets re-armed every time the service is called. Unfortunately this didn't fix the problem of the alarms stacking. The culprit is definitely su blocking. It may be RootTools or su itself. I need to update the library from 2.6 to 3.x and see if that makes any difference.
I want to send data to server at some regular interval. So, I am using AlarmManager for the same. It works fine but the problem is that when I cancel the Alarm on Date/Time change. At that time Alarm fires again before getting cancelled, so that makes my application worse as an extra data is sent to server with irregular interval.
Here is my BroadCastReceiver class with AlarmManager.
public class MyReceiver extends BroadcastReceiver{
AlarmManager mgr;
PendingIntent pi;
Intent intent;
public static boolean flag = false;
#Override
public void onReceive(final Context arg0, Intent arg1) {
if(arg1.getAction().equals("android.intent.action.TIME_SET")){
Log.d("MyReceiver", "Time set");
mgr = (AlarmManager) arg0.getSystemService(Context.ALARM_SERVICE);
intent = new Intent(arg0, TestService.class);
intent.putExtra("test", "testvalue");
pi = PendingIntent.getService(arg0, 0, intent, PendingIntent.FLAG_UPDATE_CURRENT);
if(!flag){
mgr.setRepeating(AlarmManager.RTC_WAKEUP, System.currentTimeMillis() + 10000, 5000, pi);
flag = true;
}
else{
mgr.cancel(pi);
pi.cancel();
flag = false;
}
}
}
}
Below is the Screen Shot with Logcat output that explains that after cancelling the Alarm it fires once more time just after cancelling.
As you can see in the Logcat output black arrow shows where I changed that time to cancel the Alarm and red arrow shows that after cancelling the Alarm once again it fired just before cancelling which should not happen. So, can anyone give my idea why that is happening and what should I do to restrict Alarm getting fired again before cancelling.
NOTE:- This only happens when I tried to increase date/time say from 10:00 to 11:00, works perfect when I decrease time say 10:00 to 9:00.
Not able to see the LogCat at my end, but looking at the code, I am not sure, how is the Service which gets invoked (TestService) gets killed / stopped ? I think you would need to stop it somehow. Also, its not recommended to do long running tasks within the broadcast receiver.
Have you verified that you service stop event is occuring after the mgr.cancel(pi) is fired?
Just try with some unique code with pending intent within activity and then cancel that intent using the same code.
setting pending intent in activity
PendingIntent.getBroadcast(this, code, intent, PendingIntent.FLAG_UPDATE_CURRENT);
for stopping that broadcast receiver
PendingIntent pendingIntent = PendingIntent.getBroadcast(getBaseContext(), code, intent, 0);
AlarmManager alarmManager = (AlarmManager)getSystemService(Context.ALARM_SERVICE);
alarmManager.cancel(pendingIntent);
why that is happening
First Thing is that you are using Intent Action android.intent.action.TIME_SET so It does mean that Everytime any how if the System date/time gets Changed your BroadcastReceiver will ne called Automatically.
Second you have used one static boolean flag in your Receiver class.
Now what is happening is Whenever you change your System timings the flag toggles it's state from false to true and from true to false.
That is what exactly happening in your code and logcat also shows the same that everything is working as per the code written.
So according to me there is nothing Wrong happening in the code and it's output.
what should I do to restrict Alarm getting fired again before cancelling
First thing as I think, you should not use Action TIME_SET like that to toggle flag on/off as users and developers might not remember for what they are changing time either to turn FLAG On or Off,
Better way is that,
you should handle the Service yourself by an Activity and show one ToggleButton there to manage the State of the FLAG and set and cancel the PendingIntent.
OR
And If you want to do the task of your service automatically then you just simply use the AlarmManager and set your Alarm Triggering time and Interval there only once say time is currenttime and Interval is 50000 miliseconds..
so it will obviously call the service from now onwards after every 5mins, then in your App you will only require one ToggelButton to indciate the Sync to ther server is On or Off , if user Toggle it on or off then write your AlarmManager code there in your Activity only in the toggleButtontb.setOnCheckedChangeListener(listener) , I suppose this is the better way then what you are actually implementing.
I don't understand what need to set the receiver for date change if your goal is only to send the data on server in some regular interval .
change date and time of device does not mean that your alarm wont work
at that time which you already have set before those changes .Alarmmanager work on that given duration of time which is excluding from local current date and time of device .
When setting a service to go off at particular time, I use the AlarmManager system service.
Everything goes off without a problem, service is called and actions take place.
When the alarm time is reached, the service starts, and at this point I get the system time (System.currentTimeMillis()). I'm guessing this wont be the actual time the service start. Is there a way to get the time that was set for this PendingIntent?
ie
Set alarm for 9am.
DoStuffService starts at 9am.
DoStuffService knows it was supposed to start at 9am, and uses this value for future functions.
When you create an intent for your alarm, you could put extra data, including time of the alarm, into it like this:
Intent intent = new Intent("action name");
//put extra data into the intent:
intent.putExtra("alarm_time_hours", hours);
intent.putExtra("alarm_time_minutes", minutes);
PendingIntent sender = PendingIntent.getBroadcast(getApplicationContext(), 0, intent, PendingIntent.FLAG_UPDATE_CURRENT);
AlarmManager am = (AlarmManager) getSystemService(ALARM_SERVICE);
am.set(AlarmManager.RTC_WAKEUP, cal.getTimeInMillis(), sender);
Then in your receiver or service you need to get this extra data from received intent. Use something like this:
Bundle bundle = intent.getExtras();
if(bundle.containsKey("alarm_time_hours")) {
int hours = bundle.getInt("alarm_time_hours");
}
if(bundle.containsKey("alarm_time_minutes")) {
int minutes = bundle.getInt("alarm_time_minutes");
}
Is there a way to get the time that was set for this PendingIntent?
No, sorry.
However, it should not be terribly difficult for you to determine it yourself. Following your example, if your service reports that it is now 09:00:02.36, you should be able to round down to determine that this is the 9am alarm.