Checking if an Android application is running in the background

Question

By background, I mean none of the application\'s activities are currently visible to the user?

Answer 1

You can use ComponentCallbacks2 to detect if the app is in background. BTW this callback is only available in API Level 14 (Ice Cream Sandwich) and above.

You will get a call to the method:

public abstract void onTrimMemory (int level)

if the level is ComponentCallbacks2.TRIM_MEMORY_UI_HIDDEN then the app is in background.

You can implement this interface to an activity, service, etc.

public class MainActivity extends AppCompatActivity implements ComponentCallbacks2 {
   @Override
   public void onConfigurationChanged(final Configuration newConfig) {

   }

   @Override
   public void onLowMemory() {

   }

   @Override
   public void onTrimMemory(final int level) {
     if (level == ComponentCallbacks2.TRIM_MEMORY_UI_HIDDEN) {
        // app is in background
     }
   }
}