I'm currently writing an app, what has an on-boot service. This service simply pops up a notification after a time, and update it in given periods with new info. Currently there's no need for any further battery saving, I just want the update sequence to work.
I've hit a problem tho. Created the boot BroadcastReceiver what then starts my Service. It it, I do the work via a Timer and a TimerTask. But as I saw, there's no easy way to check if the notification was deleted, and thus not try to update it, but re-create it.
What I want to do:
private Notification n;
NotifTask extends TimerTask {
public void run() {
if(n.exists){
// Update notification
}else{
n = Notification.Builder(context).[customize it].build();
}
}
}
And in the service's onStart, set up a timer what runs this task every 10 seconds.
Now, my question is: is there any way to do the "n.exists" part easily, without intents?
If you post a notification and this notification already exists, it will just get updated with the new information. If it doesn't exist it will be created. I don't think you need to do anything special to get the behaviour you want.
From the documentation for NotificationManager.notifiy():
Post a notification to be shown in the status bar. If a notification
with the same id has already been posted by your application and has
not yet been canceled, it will be replaced by the updated information.
Related
I have an Android Service (implementation of Servcie interface) which is running on a separate process compared to my real app. Unfortunately when I leave my real App (in which I clicked the Button to start my Service) and swipe it out from Task Manager, my Service gets killed as well.
I know there are a lot of questions like this here, but somehow none are targeting the Problem in my concrete constellation or they are vaguely answered.
So in my manifest I have something like:
<application ...>
<activity .../>
<service Android:name="MyService"
Android:label="MyLabel"
Android:export="false"
Android:process=":MyRemoteProcessName" />
</application>
I first have played around with an IntentService, but also switched to an own implementation of the Service Interface (eliminating the IntentService to be the point of failure) which looks something like:
public class MyService extends Service {
private ScheduledExecutorService scheduledWorker = Executors.newSingleThreadScheduledExecutor();
#Override
public void onStart() {
// Init components
startForeground(this, MyNotification);
}
#Override
public int onStartCommand(Intent i, int startId) {
// Execute Work on Threadpool here
scheduledWorker.execute(new ScheduledStopRequest(this, startId), 5, TimeUnit.Minutes);
return START_REDILIVER_INTENT;
}
// Overwritten onDestroy-Method
#Override
public void onLowMemory() {
Log.e(LOG_TAG, "On Low Memory called!");
}
#Override
public IBind onBind() {
// Dont't want to let anyone bind here
return null;
}
// Simply tries to stop the service after e.g. 5 Minutes after a call
private static class MyRunnable implements Runnable {
// Constructor with params used in run method..
#Override
public void run() {
mReferenceToMyService.stopSelfResult(startId);
}
}
}
I'm starting my Service in an onClick-Listener on a special button, with an explicit Intent, which kinda looks like the following:
#Override
public void onClick(View v) {
Intent i = new Intent(this, MyService.class);
startService(i);
}
My Intention is to keep the Service running when the user leaves the app, so that the Service can finish downloading and storing some important data. When the user comes back to my app again, he can view the data (That's why I'm executing it in a separate process). So is this possible?
My assumption right now is, that Android somehow notices my Service is just being used by my App (due to missing IntentFilters in Manifest or explicit call rather than by filter?!) and thus kills it immediately when my App is closed (even when running as ForegroundService as you can see above).
Does it seem possible to you and might some changes in the call of the service fix this problem or am I getting the concept of a service wrong?
(One last note: onLowMemory-Method doesn't get called -> No log entries.)
So, according to your hints (and so new keywords for me to look for) and after some additional research by myself, I think I have solved my problem. During my research I have found an very interisting blog post on this topic, maybe also for you, which is why I would like to share it with you: http://workshop.alea.net/post/2016/06/android-service-kill/ .
After verifying and going through the steps in this article everything seems to work fine (so startForeground seems to solve the problem). I want to point out here, that I have only tested it, with my service instance still running in separate process, so manifest entries as is above.
The actual thing which really confused me at the beginning was my android studio debug session being killed everytime, just after swiping out my app from recent apps (menu). This made me think my service being killed by the system as well. But according to the article (I have added some logs to the callback methods provided) when
Opening my app
starting service
swiping out app
starting app again and finally
calling service again,
I only received callbacks to the methods as if my service would still be running. Having an explicit look at DDMS (tool) also prooved my 2nd process, and thus my service, being still alive. Having verified this, I then cleared all my app data and repeated the steps above (excluding step no. 5). Having had a look in the database afterwards, prooved the data having been downloaded by the service.
For the curious of you:
The process of swiping out my app from recent apps (and thus having the onTaskRemoved callback method being called) lead to another problem. It somehow increases the startId parameter of onStartCommand by 1 so that my DelayedStopRequest malfunctiones and doesn't stop my service anymore.
This means: Repeating above steps 1 - 3 makes me receive startId = 1 in onStartCommand. By calling stopSelfResult(1) later on (which was the latest startId) it returnes false and the service keeps running. Continuing to follow step 4 + 5 then, makes onStartCommand being called with startId = 3 (but should actually be 2! which is skipped somehow). Calling stopSelfResult(3) with parameter 3 later on is then going to stop the service again (also visible in screenshots).
I hope my answer is correct so far (, understandable) and also helpful for you. Thank you for all of your answers which provided beneficial input and also pointed me to the solution. The android version I have been working with is:
4.1.2 - Jelly Bean | API Level : 16
I also added screenshots of the log entries from DDMS (imgur is rejecting my uploads so you'll temporarily have a link to my dropbox):
screenshots from logs from DDMS
Unfortunately running service in a separate process does not help you. I think there is no way you can prevent your service from being closed if user removes its task. You can however restart your service overriding onTaskRemoved. See this answer.
If you want to run this service class indefinitely after closing the app also.. you should use Alaram Manager class ..
public void scheduleAlarm() {
// Construct an intent that will execute the AlarmReceiver
Intent intent = new Intent(this, LocationListnerServiec.class);
// Create a PendingIntent to be triggered when the alarm goes off
final PendingIntent pIntent = PendingIntent.getBroadcast(this, MyAlarmReceiver.REQUEST_CODE,
intent, PendingIntent.FLAG_UPDATE_CURRENT);
// Setup periodic alarm every 5 seconds
long firstMillis = System.currentTimeMillis(); // alarm is set right away
AlarmManager alarm = (AlarmManager) this.getSystemService(Context.ALARM_SERVICE);
// First parameter is the type: ELAPSED_REALTIME, ELAPSED_REALTIME_WAKEUP, RTC_WAKEUP
// Interval can be INTERVAL_FIFTEEN_MINUTES, INTERVAL_HALF_HOUR, INTERVAL_HOUR, INTERVAL_DAY
alarm.setRepeating(AlarmManager.RTC_WAKEUP, firstMillis,
60000, pIntent);
}
Use this method for keep checking the service class is on or off.. By using this method Your service class will keep working after destroying of you application.
I'm so lost with all that workflow of notifications and services in Android. My sceneario is this:
I have an Android application that communicate to a MySQL database through a web-service using JSON-RPC. The data retrieved from the service will be displayed in the application.
The data will get updated over time, so the application needs to listen for changes of this and, if a change occur, show a notification and update the data displayed in the app.
To listen for changes I will need to run an "infinite"(until the app is destroyed or maybe until the app destroys it) thread that from time to time will call a method on th web-service which will return the changes since the last check.
UPDATE: Ok, I have been trying using Service and IntentService, but non of them fits my needs: a Service execute in the Main Thread, so If I perform an infinite loop there my app will freeze, IntentService has it's own worker thread but there is no comunication with the App, and I need it, or at least I need a way to know if the app is in foreground (in this case the notification will not popup but the data will be passed and updated) or in background (int this case the notification will pop up and on click it will direct the user to the app with the updated data)
#1 You can fire a broadcast message from your Service and define a Broadcast receiver in your Activity to receive this broadcast.
SEND BROADCAST-from Service
Intent i = new Intent("ALERT_CHANGE");
i.putExtra("DATA","News");
sendBroadcast(i);
RECEIVE BROADCAST-in Activity
registerReceiver(uiUpdated, new IntentFilter("ALERT_CHANGE"));
private BroadcastReceiver uiUpdated= new BroadcastReceiver() {
#Override
public void onReceive(Context context, Intent intent)
{
String DATA = i.getStringExtra("Data");
txt.settext(DATA);
}
};
Ok, after a lot of testing and thanks to the info given here I finally found a way to handle with the issue, so I will share it here:
On the IntentService I have a public static AtomicBoolean to control the end of the loop and be able to stop the service.
Then to determine if the Activity is in foreground or not I use the method suggested here https://stackoverflow.com/a/5504711/3107765
With the difference that I use the static modifier there, so I can check it from the service.
if the activity is in foreground I send a broadcast as it was suggested here by Eu. Dr. otherwise I use a notification that once clicked will let the user to the activity.
I was playing around with services and dialogs, and I got a doubt. Within a dialog, I am starting a service like this:
Intent lock = new Intent(getActivity(),AppLockService.class);
getActivity().stopService(lock);
getActivity().startService(lock);
Now the first time I call the dialog through
dialog_name.show(getFragmentManager(), "dropbox");
Upon pressing the OK button, the intent is launched. Now later, during the same app execution, the dialog is triggered again ( which is according to my code logic -- nothing wrong here). The code in the dialog then stops the previously triggered intent and starts the new intent.
My question is this:
lock is a local intent variable as per my definition. So how does it know that it has to stop that particular service I have triggered here the first time? Would someone please explain this to me?
You don't have to keep track of the service in a variable because Android does it for you.
The way that the OS treats a service is that it will not allow more than one instance of the service be to running at any time.
So at any moment there are 0 or 1 instances of your service. If there are 0, no problem, the OS will ignore the call to StopService. If there is 1 instance, it must be the instance you started previously - so it will be stop that one.
i have created a service (EmailService) that sends email ... each time i need to send an email with my app, it starts the service and pass the id of the email via an intent...
i am using startforeground(id_of_email, mynotifcation); to prevent it from being killed and to show a notification to the user of the status of the email sending.
i need to allow the user to send multiple emails at the time, so when the user needs to send another email, it again calls startservice with a new intent(different id of email)...so it calls startforeground(new_id_of_email, mynotifcation); again.
the problem is that the new call to startforeground overwrites the previous notification... (so the user loses the previous notification and doesn't know what is going on with his previous email)
Looking at the Service.startForeground() source shows that multiple calls to startForeground will only replace the currently shown notification. In fact, the call to startForeground is identical to stopForeground(), only with removeNotification set always set to true.
If you wish for you service to display a notification for each email in progress, you will have to manage each notification individually from the service.
public final void startForeground(int id, Notification notification) {
try {
mActivityManager.setServiceForeground(
new ComponentName(this, mClassName), mToken, id,
notification, true);
} catch (RemoteException ex) {
}
}
public final void stopForeground(boolean removeNotification) {
try {
mActivityManager.setServiceForeground(
new ComponentName(this, mClassName), mToken, 0,
null, removeNotification);
} catch (RemoteException ex) {
}
}
http://grepcode.com/file/repository.grepcode.com/java/ext/com.google.android/android/4.3_r1/android/app/Service.java#Service.startForeground%28int%2Candroid.app.Notification%29
One can also use STOP_FOREGROUND_DETACH flag.
Quoting from the documentation :
STOP_FOREGROUND_DETACH
added in API level 24 int STOP_FOREGROUND_DETACH Flag for
stopForeground(int): if set, the notification previously provided to
startForeground(int, Notification) will be detached from the service.
Only makes sense when STOP_FOREGROUND_REMOVE is not set -- in this
case, the notification will remain shown, but be completely detached
from the service and so no longer changed except through direct calls
to the notification manager.
Constant Value: 2 (0x00000002)
So, before a repeated call to startForeground() you can call stopForeground(STOP_FOREGROUND_DETACH);. This will detach the notification and repeated calls to startForeground() will not make modifications to it, if you use a different notification-id.
Further, the "detached" notification, now, does not represent the "ongoing service" and hence can be removed by user with a swipe.
BONUS :
For compatibility, one can use ServiceCompat class and its static method ServiceCompat.stopForeground(MyService.this, STOP_FOREGROUND_DETACH) as is documented here.
I created a utility class to manage foreground service notification(s) based on #zeekhuge's answer. You can find the snippet here: https://stackoverflow.com/a/62604739/4522359
I'm developing a location based alarm which is an Android application.
All the coding part has been done.
But the alarm alert dialog is not displaying when the application is closed.
Please help me, I'm trying to pop up the alarm even when user is using another application or is in the home screen.
The code of my alarm at the moment is shown below:
final MediaPlayer mp = MediaPlayer.create(LocAlarmProject.this, R.raw.airtel);
mp.start();
// LocAlarmProject.this below is what's causing the problem:
final AlertDialog.Builder builder=new AlertDialog.Builder(LocAlarmProject.this);
builder.setTitle(disp_title);
builder.setMessage(disp_desc);
builder.setIcon(R.drawable.alarm);
builder.setPositiveButton("OK", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int which) {
mp.stop();
}
});
builder.show();
I am pretty sure you are looking for Service.
Copied and Paste:
A Service is an application component representing either an
application's desire to perform a longer-running operation while not
interacting with the user or to supply functionality for other
applications to use. Each service class must have a corresponding
declaration in its package's AndroidManifest.xml. Services
can be started with Context.startService() and Context.bindService().
Use Notification service to keep track of the status.....visit......http://developer.android.com/guide/topics/ui/notifiers/notifications.html
The proper way to do this requires a few steps. Sorry, it's not trivial if you haven't done it before:
First, you're going to use Android's built-in AlarmManager to schedule the time you want your app to be activated. You schedule a new alarm with the time to wake up and a PendingIntent.
Second, create your PendingIntent that's used to activate your app for the time to show the alarm.
Third, you can handle this Intent several ways, the most common is to create a class that extends BroadcastReceiver to receive the Intent. This class is notified when it's time to show the alarm. The Intent that you created and put inside your PendingIntent is passed to its onReceive() method. You pass this information to your app to display the alert dialog. --- You can alternatively just register your main app to receive the Intent instead, then override the onNewIntent(Intent) method in your Activity.
Four, register your BroadcastReceiver in your AndroidManifest.xml file. This is also the place to register this receiver to listen for the Intent you created. You do this using the <intent-filter> tag.
Five, (optional) if you want your alarm to display even if the phone is asleep, and you want to make sure it doesn't go back to sleep before the user acknowledges the alarm, you'll need to obtain a WAKE_LOCK to do so.
The reason this is preferable to using a Service is it doesn't consume resources just to wait for the alarm, and also it still works if Android decides to kill your app free up memory. Good luck and happy coding!