I am developing an app which will keep track of the time when a user's phone is "not used".
Basically, an app which gets activated as soon as a user presses unlock or in the event of an incoming call. I have written a BroadcastReceiver which notifies a background service to start keeping track of time during which the phone is not being used, and will show the activity as soon as the user presses to lock.
My problem is that the services sometimes gets shut down without notifying. Can I write one more service which can periodically check whether the master service is running and toggle it in case it's shutdown? Or is there any other better way to do so?
A started service can use the startForeground(int, Notification) API to put the service in a foreground state, where the system considers it to be something the user is actively aware of and thus not a candidate for killing when low on memory. (It is still theoretically possible for the service to be killed under extreme memory pressure from the current foreground application, but in practice this should not be a concern.)
Yes you can start another services within your service. Actually you always do this but you are not aware of it. I mean when you call getSystemService(....) initializer in your service , you use another service which is declared by android.
i am not that experienced but yes you should be able to start another service by sending an intent to the other service if you like, service may be killed by the system if it is under heavy memory pressure according to http://developer.android.com/reference/android/app/Service.html.
You should be able to check if your service is running or not.
Related
I'm developing a player app.
For this reason, it uses a foreground service to handle the playback.
Until recently the service was bound to my activities.
This is not the case anymore.
Since then, some specific devices (mostly Pixel 1/2/3) have been killing my app 1 minute after the screen has been turned off
The service is a foreground service not bound to anything.
Why would the device kill it?
As soon as the app is excluded from the device-optimized apps list the issue is solved
I'm not providing code, because I'm just trying to understand if this situation makes sense and if so what should I do to prevent this
BTW the app is using a receiver to act on Screen_ON/OFF messages. That's how I can see in the logs that the player service onDestroy() method gets killed exactly 1 minute after the screen has been turned off
what should I do to prevent this?
The key point here to keep the service alive is as said in official documentation :
While an app is in the foreground, it can create and run both
foreground and background services freely.
so, we can conclude that keeping the work in foreground and visible to the user has very minimal chances of being killed. And to do so we need to know that how android gets the idea that this process is in foreground ?
Here are the criteria's at which a process is said to be in foreground:
It has a visible activity, whether the activity is started or
paused.
It has a foreground service.
Another foreground app is connected to the app, either by binding to
one of its services or by making use of one of its content
providers. For example, the app is in the foreground if another app
binds to its:
-IME Wallpaper service
-Notification listener
-Voice or text service
If none of those conditions is true, the app is considered to be in
the background.
If none of the above criteria is fulfilled by your app process then thats the reason of your service being killed.
You can read more on this topic here :
Foreground service being killed by Android
I have started a service from my application and from that service a worker thread is started .I want my service to run even application goes background and until the user kills/exits the application.
But some cases my service got killed due to low memory ,then used sticky service or making the app to foreground to restart the service.
My issue is I dont want to lose the data between service ending and restarting time ,so is it possible to start another thread from service ondestroy method, but in this case how we can control that thread.
Please let me know is it the right approach ,and is this usecase achievable
I want my service to run even application goes background and until the user kills/exits the application.
This is not possible. The user can always get rid of your app, via Force Close in Settings, or via some device's version of the recent-tasks list.
But some cases my service got killed due to low memory
No, your process is terminated for low memory.
My issue is I dont want to lose the data between service ending and restarting time ,so is it possible to start another thread from service ondestroy method
No, because your process is being terminated.
Please let me know is it the right approach
Probably not. Very few apps need a service that runs constantly, which is why Android, and its users, go to great lengths to control such services. I would recommend that you try to find some solution to whatever your problem is that does not need a service running constantly.
I need to create a service that monitor sms received and sent.
The only work of the process will be listen to the sms and save them in the database
But, this service can't die, I can't stop to listen.
After some research, I found that I can start a service with startForeground.
Documentation of startForeground:
A started service can use the startForeground(int, Notification) API to put the service in a foreground state, where the system considers it to be something the user is actively aware of and thus not a candidate for killing when low on memory. (It is still theoretically possible for the service to be killed under extreme memory pressure from the current foreground application, but in practice this should not be a concern.)
Before I start to program the service, I thought in asking for a better option, if have one.
So, somebody knows a better way?
You should read up on Android fundamentals. You don't need a constantly running service. Just register a broadcast receiver for the appropriate intent and send an intent to your service from there (Android will automatically start it as necessary).
What happens to a service started by BOOT_COMPLETE after system kills it for memory?
Will it ever be restarted without rebooting the phone? Is it possible to restart it somehow?
What is the best practice to avoid as much as possible an important service from being killed?
Will it ever be restarted without rebooting the phone?
Possibly. If it truly was because "system kills it for memory", and you return an appropriate value from onStartCommand() (e.g., START_STICKY), it should be restarted at some point in the future. If the service was killed due to user action (e.g., Force Stop in the Manage Services screen in Settings), it will not be restarted.
What is the best practice to avoid as much as possible an important service from being killed?
First, design your application to not rely on an everlasting service like this. 99.44% of Android applications do not need a service that runs continuously, let alone one that starts doing so at boot time. Android device users hate developers who think that their apps are sooooooooooooo important that they have services running all the time -- that's why we have task killers, Force Stop, and Android killing services due to old age. For example, if you are checking for new email every 15 minutes, use AlarmManager and an IntentService, not a service that runs forever.
If you can demonstrate -- to me and to your users -- that yours is among the 0.56% of applications that really do need a service that starts at boot time and runs forever, you can use startForeground(). This will indicate to the OS that your service is part of the foreground user experience. You will have to display a Notification, ideally to allow the user to shut down your service cleanly if and when the user no longer feels that it is justified.
If you need to restart the service then you should use AlarmManager to check up on the service in a separate BroadcastReceiver, but nominally when a service is killed by the system for memory it will not get automatically restarted.
You may want to take a look at START_STICKY
Use the AlarmManager to periodically send an Intent-- receive the intent and make sure your service is running.
I am currently writing my first Android application and I keep running into references to background and foreground services. Since I intend on using a service in my application I was hoping to get a clarification between the two and how they are used.
Perhaps this will answer your question:
A started service can use the startForeground API to put the service
in a foreground state, where the system considers it to be something
the user is actively aware of and thus not a candidate for killing
when low on memory. By default services are background, meaning that
if the system needs to kill them to reclaim more memory (such as to
display a large page in a web browser), they can be killed without too
much harm.
More info can be found here
Foreground: The process relies on onPause() and onResume()...i.e you play music player and pressing pause and play
Background: The process which runs without user interaction i.e receiving a message, incoming call, receiving mails, or setting alarms. The method used here is onStart() and onStop().
For example, check it on your phone. Create an alarm at 6:30am. When the system clock reaches 6:30am it fires. In order to kill the alarm service, just go to menu-->settings-->application-->Running service-->click stop service. It stops the alarm service even when your system reaches the time it won't fire.
Foreground Service is used when User is interaction with application and when Service is doing something visible to user. Background Service is used when even user close application (discard from recents) and when Service is doing something not visible to user like downloading data from server, load data from a ContentProvider etc.. And Foreground Service is less likely to be killed by system on low memory.