Android 8's battery consumption improvements are nice to the user but I am a bit afraid if my service will work as expected.
First of all: Thank you for any suggestions but I cannot just schedule my service. I want to make a OK Google-like keyword listener running in the background all the time. It will be based on the open source pocketsphinx-android library. I know that this will consume much battery power and I will inform the user about this.
Can we create a permanent background service on android 8+ ? I need to target android 8 in gradle because I was expecting some bugs with older targets. I also don't want to annoy a user with a foreground service which permanently shows a notification in the status bar.
[https://developer.android.com/about/versions/oreo/background.html] - Is there really no way of making permanent background services for my use-case (but preferably for all use-cases) possible?
Unfortunately, it's not possible to use a background service and don't show a foreground notification on Android 8.0 and higher.
The only one way that it might work is if you stick your app to Google APIs such as Voice Actions API.
As far as I know there is no a good work around and most apps like WhatsApp are still targetting Android API 24.
For what is worth, I am sharing me experience on that:
It's partially possible to use a background service and not showing a foreground notification on Android 8.0 just made some experiments and ended up with this:
Just create a notification channel with IMPORTANCE_NONE, and the notification will still exist, but will not be displayed in status bar.
Code excerpt:
NotificationChannel channelService = new NotificationChannel(
YOUR_SERVICE_CHANNEL_ID,
YOUR_CHANNEL_HUMAN_READABLE_NAME,
NotificationManager.IMPORTANCE_NONE);
channelService.setSound(null, null); // let's be quiet : no sound
channelService.setLockscreenVisibility(Notification.VISIBILITY_SECRET); // not on lock screen
// Register the channel with the system; you can't change the importance
// or other notification behaviors after this
// changes needs to uninstall app or clean app data, or rename channel id!
notificationManager.createNotificationChannel(channelService));
This way, the notification will not be displayed when your app is running in foreground.
Not a perfect solution:
When your app goes in background (i.e., you open another app), the "Android system" app displays a notification about "(your) app being running in the background".
So, this is not great, but, from my point of view, it's a bit better than before.
Related
I want to get the location of the device once when the service is running in the background (the tracker monitors the change in the database and then executes the code that should get the geolocation of the phone). I encountered a problem: the program receives location data when the application is running, but when it goes into the background, the location data stops being received in a few seconds. I tried all the codes and options that I could find, but everything stops working when the program goes into the background. For this I use AndroidStudio Java. So how do I implement this and is it even possible? Thanks.
On Android there are two types of Services- foreground and background. Background (the default) on modern Android are killed 2 minutes after your app is no longer in the foreground. Foreground services are kept for longer, require you to have a notification so the user knows you're tacking him (think of Uber and the notification you can't swipe away you get while its running), but can still be killed for resources if other apps need it. You cannot rely on any Service running permanently.
So the answer is going to be either Foreground Service, or its going to be a completely different architecture for your program. The second really depends on exactly when and why you want to get the location.
There are many limitations on getting on getting location in background, refer to this
Do you target API level 29 or up? if yes, have you add ACCESS_BACKGROUND_LOCATION permission in manifest? If this is not declared, app can only access location while in foreground.
Even after declaring ACCESS_BACKGROUND_LOCATION permission, app can only get location data a few time in an hour due to limitations. Maybe you can consider using foreground service instead to avoid such limitations.
I am building an app that is needed for a research experiment.
The experiment is entirely based on users responding to notifications that are shown at somehow random intervals.
What is the best way to do this so that each notification will definitely be shown to the user?
WHAT IS DONE SO FAR
I have used AlarmManager and broadcast receiver but notifications stop showing up after some time. Notification Channels (with id) are used too.
I suspect the operating system removes the app after it has stayed in the background for a while.
Can anyone help to explain the best way to get the app to show notifications regardless?
Since this is an app for research, users are well aware of any slow performances, or battery usage. The only priority is to ensure that notifications show up. Without this, the whole experiment will fail.
Any help or pointers will be great! Thanks!
I'm not sure what method you've used to show notifications so I'm giving a general guidance.
You will need to use a background service which keeps running even after the app has closed. A background service can be killed by the android OS if its running low on memory, so you'll have to give permission to your app to autostart.
If you want even more reliability, you should use a Foreground service. This way you can give high priority to your notification service.
But it would be much simpler to integrate Firebase Cloud Messaging into your app than implementing your own NotificationBuilder service.
Working with Android 8.1 and above versions, I see that a notification is always displayed on the screen without being able to clear it. Just wanted to see if there is a way to run the service without displaying any notification?
http://android-devhelp.blogspot.com/2015/12/making-service-run-in-foreground.html says we can do it but sure how reliable this is.
Looking for any suggestion.
No, you cannot run a foreground service without a persistent notification. This is both for power purposes and clarity for the user. The blog you reference is dated December 2015, which was shortly after Marshmallow (Android 6) was launched. The rules have gotten much more strict.
Depending on what you need to do in the background, you could use JobScheduler or the new WorkManager. Good luck!
After a user opens my application I don't want them to be able to get out. So when they press the home or back button it doesn't let them exit the app. I know there are ways using a service to keep the app always running in the background, but I don't even want them to even exit.
Is this even possible, if so how? Without having to hack the kernel.
I know this sounds odd, but it is not for a commercial app, but for my lab, it will never be on GooglePlay. The tablets will be given to little kids and they will take a test on it, so I can't have them using youtube or anything else.
Related post: Android, How to make the task of the app unclosable? Only closable by task killing
The answer by CommonWare seems to indicate that kernel hacking is the only way, but is it?
Also I am using Android L.
there is no official support yet - there will be support with android L via the Task locking API
The L Developer Preview introduces a new task locking API that lets
you temporarily restrict users from leaving your app or being
interrupted by notifications. This could be used, for example, if you
are developing an education app to support high stakes assessment
requirements on Android. Once your app activates this mode, users will
not be able to see notifications, access other apps, or return to the
Home screen, until your app exits the mode.
https://developer.android.com/preview/api-overview.html
EDIT: as you said you use L this got obsolete - but I leave it here as a hint for others
said that - you are also able to get this kind of work without root today if you have to ( e.g. kiosk mode app on a certain hardware ). It is not simple - and no solution that works for all devices - but if you need it you can get it work with tricks like:
- reacting on home-screen intent ( and setting it as default )
- when you go to background - bring your self foreground again
- ..
It seems google has some thing called COSU for setting up single-purpose devices
Android 5.0 Lollipop introduced two new ways to configure Android
devices for a single purpose:
With app pinning, the device user can temporarily pin specific apps to the screen.
With lock task mode, a user can’t escape the app and the Home and Recents buttons are hidden. Additionally, lock task mode gives the IT
administrator a more robust way to manage COSU devices, as discussed
below.
and
As an IT administrator, you can configure Android 6.0 Marshmallow and
later devices as corporate-owned, single-use (COSU) devices. These are
Android devices used for a single purpose, such as digital signage,
ticket printing, point of sale, or inventory management. To use
Android devices as COSU devices, you need to develop Android apps that
your customers can manage.
from here
and there is a code lab for it here
for earlier versions of android here i founded How-To Create a Working Kiosk Mode in Android which shows some hacks for disabling buttons and restarting the application after boot and lock. note that most of these hacks, don't work on android 6 and later
I wonder if it is possible to have notifications show up even if the app is turned off.
say for example I have an app and I set some kind of notification for 13.00 the next day and then turn the app off or restart my phone or something.
Is it possible to still get a notification in the notification bar with some text that starts the app or do the app need to run in the background to be able to use notifications?
if it is possible, what is the best way to do this? (get a notification at a certain time that starts the app) and if not, how do you recommend doing notifications?
The type of notifcations I want to do are reminder notifications.
thanks for all help!
A combination of AlarmManager and Service will help you to perform the task you are looking for, I had performed this thing.Check out the android tutorials for it.
What you're looking for is a background service. See this Android Services tutorial.
In the background service, your app should check periodically and when necessary, create and issue new notifications. See this Android Notifications tutorial.
The background service can be set to automatically start when the phone is restarted, and to re-issue any uncleared notification again.
Many apps such as Gmail already do this. Although you must be careful in resource usage or Android might kill your service.