How can I tell if my app is in the background?

Question

I need to start a foreground service from my app based on a remote event. Most of time when this happens the user will be on the app and the app will be visible, but on a small amount of the time the user will be on a different app or the screen will be off.

So I want to have logic that decides on Android 8+ whether it should call startService or startForegroundService based on whether the app is on the background or not. So how can I know this?

Edit: I did see on another answer that you can just keep a flag for onPause and onResume but I was hoping there would be a better way by now?

https://stackoverflow.com/questions/5504632/how-can-i-tell-if-android-app-is-running-in-the-foreground — IntelliJ Amiya, Nov 24 '17 at 16:22
I had seen that answer but it is from 2011, is that really the best way still? — casolorz, Nov 24 '17 at 16:23
https://stackoverflow.com/questions/26879951/how-to-know-if-my-application-is-in-foreground-or-background-android — IntelliJ Amiya, Nov 24 '17 at 16:25
Another approach is to use `ProcessLifecycleOwner` from arch. components - https://android.jlelse.eu/android-architecture-components-processlifecycleowner-26aa905d4bc5 — John O'Reilly, Nov 24 '17 at 17:24
Are you using Java or Kotlin, cause I have a nice Kotlin solution — Rainmaker, Nov 24 '17 at 17:38
On this app java. But wouldn't mind a kotlin solution for another app I'm starting on. — casolorz, Nov 24 '17 at 17:38

Rainmaker · Answer 1 · 2017-11-24T17:45:57.363

A Kotlin solution from Google I/O 2016

class YourApplication : Application() {

      override fun onCreate() {
        super.onCreate()
        registerActivityLifecycleCallbacks(AppLifecycleTracker())
      }

    }


    class AppLifecycleTracker : Application.ActivityLifecycleCallbacks  {

      private var numStarted = 0

      override fun onActivityStarted(activity: Activity?) {
        if (numStarted == 0) {
          // app went to foreground
        }
        numStarted++
      }

      override fun onActivityStopped(activity: Activity?) {
        numStarted--
        if (numStarted == 0) {
          // app went to background
        }
      }

    }

How can I tell if my app is in the background?

1 Answers1