Develop Reference

How to make sure a service that runs when the Application is closed does not get killed?

I am developing a Fitness Application as part of my Bachelor Thesis, and want to keep track of step counts even when the application is completely closed. For this I am currently starting a service that utilises the built in Sensors "Step Counter" and "Step Detector". After some testing I found out that sometimes my Service gets killed and no longer keeps track of the steps taken. I left the phone on my desk overnight and walked around in the morning then I opened the application and the steps I took in the morning were not tracked, whereas when I close the application and immediatly start walking the tracking of steps still works.
Is there a way to make sure that my Service does not get killed?
Would the use of a Foreground Service solve my issue and are there any alternatives to using a foreground service?

Foreground Service is the only way if you want to assure that the service will not be killed.
The reason for this is that the foreground service always shows a notification to the user and can be killed by the user if he wants to, this is especially important if you want to know for sure what runs on your device.
All previous methods of making permanent running services are deprecated starting from android 9, when a new privacy policy was introduced.

Basically you need to keep service running in the background,
Here is the workaround to achieve this
https://stackoverflow.com/a/58162451/7579041
above link is useful for Stock ROM & Custom ROM Devices like OnePlus, OPPO, VIVO, etc
I hope this will help you out

Android Gps Tracker not getting timely updates

I have an open source gps tracking application that has been around for many years. Recently, I have been getting complaints that in android nougat, instead of getting updates once a minute, people are getting updates from the phone once every five minutes when the phone is unplugged.
There is something going on with the power saver mode even though we tried turning it off.
Is there a way to force a phone to get gps updates at a specified time when unplugged?
Here is the code if anyone wants to see it but I don't think it's a problem with the code. It has been very stable for years.
https://github.com/nickfox/GpsTracker/blob/master/phoneClients/android/app/src/main/java/com/websmithing/gpstracker/LocationService.java
thanks.

One change in Android 7/Nougat was that the Doze is now "more aggressive". In Android 6/Marshmallow the doze mode kicked in when the screen was off, the device was running on battery and it was stationary.
(This is documented in Optimizing for Doze and App Standby)
Now in Android 7 the conditions are just screen off and running on battery.
(This is documented in Android 7.0 Behavior Changes)
Apps can be white-listed to be exempt of the restrictions if they break the core functionalility of it. In your case they do as the GPS tracker needs to record coordinates in real time.
There's a list of Acceptable Use Cases for Whitelisting
This includes:
Task automation app | App's core function is scheduling automated
actions, such as for instant messaging, voice calling, new photo
management, or location actions.
Users can white list an app manually on their own in the device settings or whitelisting can be requested by the app and approved or rejected by the user.
This is covered in Support for Other Use Cases
Quoting:
An app can fire the ACTION_IGNORE_BATTERY_OPTIMIZATION_SETTINGS intent
to take the user directly to the Battery Optimization, where they can
add the app.
An app holding the REQUEST_IGNORE_BATTERY_OPTIMIZATIONS permission can
trigger a system dialog to let the user add the app to the whitelist
directly, without going to settings. The app fires a
ACTION_REQUEST_IGNORE_BATTERY_OPTIMIZATIONS Intent to trigger the
dialog.
The user can manually remove apps from the whitelist as needed.
The last point is important of course, but luckily the whitelisting status can be checked programmatically:
An app can check whether it is currently on the exemption whitelist by
calling isIgnoringBatteryOptimizations().
So, dealing with the Doze mode is one thing to study at least.
Another issue is keeping the Service running in general. But the Service getting killed by the system might result in more random time intervals. There are of course the classic things like using START_STICKY or running as a foreground service.

Android M: How to programmatically disable doze mode

I have a foreground notification service that continuously monitors user's actions, using ActivityRecognition, and writes them to AWS anytime user's state changes. It works good for some time. However I noticed when user is idle for longer time, such as user is sleeping overnight, then the app (activity and service) silently dies. I assume this is because of doze mode (because I whitelisted the same app on a different phone and it is working fine for over 2 days now)
How to WhiteList app in Doze mode Android 6.0 gives good overview on how to disable doze mode with user intervention. But #commonsware blog below suggests about Google 'possibly' banning the apps that show the corresponding popup box
https://commonsware.com/blog/2015/11/11/google-anti-trust-issues.html
Note: Google Play policies prohibit apps from requesting direct exemption from Power Management features in Android 6.0+ (Doze and App Standby) unless the core function of the app is adversely affected.
Can someone help me in understanding what features can possibly comprise "core functions", so Google would not ban my app. We know doze mode doesn't affect some apps like WhatsApp
EDIT
I see this on Samsung phones with 6.0.1

Android does not kill services in the background with Doze. Per the ActivityRecognitionApi documentation:
To conserve battery, activity reporting may stop when the device is 'STILL' for an extended period of time. It will resume once the device moves again. This only happens on devices that support the Sensor.TYPE_SIGNIFICANT_MOTION hardware.
Therefore it is entirely expected to have a significant period of time where you won't get any activity recognition callbacks. In those cases, you can assume that the last received activity (STILL) is still applicable.

Doze app state implications for a voice recording app

I have an android app which records voice using a service - and a thread inside the service(obviously the app can record while in background..)
The app will be affected by the new Doze app state?
https://developer.android.com/training/monitoring-device-state/doze-standby.html#whitelisting-cases
I don't have a phone with 6.0 yet and the simulator cannot record voice in general...

If your service is running in the foreground (with an associated notification) when the device enters Doze mode, it should not be affected according to a comment by Dianne Hackborn to this post. See a documented experience that seems to prove this behavior here.
On the other hand, tests show, that access to certain sensors like GPS are restricted in Doze mode, so this might also apply to the microphone.
Since Doze mode is poorly documented up to now, unfortunately at this point you probably do not get around running your own tests on a physical device.

Yes, every app can be "killed" by Doze. If your service runs in foreground you can avoid App Standby however. Remember that asking to the user to put the app in the whitelist it's prohibited from Google Terms of services, so you can't do it. If you want to do something like that you need to add a permission to your manifest and with cross fingers hope in the Google review of your app.

Prevent that the app get stopped or paused by the OS

I'm developing and Android application on CodenameOne that needs to send a web request every 5 minutes even when minimized. How can I achieve this behavior in order to prevent that the request get stopped or paused by the OS?

You cant do that from the activity, you'll need to create background service.
http://developer.android.com/training/run-background-service/create-service.html

Use AlarmManager to set up your every-five-minute operation. Have it trigger a BroadcastReceiver, which in turn passes control to my WakefulIntentService (or your own IntentService that handles the WakeLock, that you will need so that the device stays awake while you do your work). Have the service do the "web request".
This is still not 100% guaranteed:
The user can Force Stop you from Settings, in which case your alarms are gone and nothing will happen until the user manually runs your app again
The user might block alarms from firing on certain devices, like various SONY Xperia models, that offer "stamina mode" or the equivalent
However, it is the best that you are going to get, short of rolling your own Android OS version.

The other guys answers are correct that you need to create a service but they somehow ignored the mention of Codename One.
Under Codename One you need to create a native directory for android and just place the service source code there (just use a blank service class that doesn't really do anything). Then you need to add to the build arguments the option android.xapplication where you would state the service XML attributes.
Having said that what you are trying to do is VERY wrong and you shouldn't do it in Android! You will drain the battery life from the device in no time and the service will be killed by the OS eventually (since it will be a battery drain). The solution is to send a push notification to the device to wake up the application.

In Android 9 and newer you can prevent your App falling asleep with a battery setting.
Long click on your App -> App info -> battery -> optimize battery consumption
Here add your App from the list.Hint: maybe the menu entries have a different name, depending on your phone.