How to check if activity is in foreground or in visible background?

This is what is recommended as the right solution:

The right solution (credits go to Dan, CommonsWare and NeTeInStEiN)
Track visibility of your application by yourself using
Activity.onPause, Activity.onResume methods. Store “visibility” status
in some other class. Good choices are your own implementation of the
Application or a Service (there are also a few variations of this
solution if you’d like to check activity visibility from the service).

Example
Implement custom Application class (note the isActivityVisible() static method):

public class MyApplication extends Application {

  public static boolean isActivityVisible() {
    return activityVisible;
  }  

  public static void activityResumed() {
    activityVisible = true;
  }

  public static void activityPaused() {
    activityVisible = false;
  }

  private static boolean activityVisible;
}

Register your application class in AndroidManifest.xml:

<application
    android:name="your.app.package.MyApplication"
    android:icon="@drawable/icon"
    android:label="@string/app_name" >

Add onPause and onResume to every Activity in the project (you may
create a common ancestor for your Activities if you’d like to, but if
your activity is already extended from MapActivity/ListActivity etc.
you still need to write the following by hand):

@Override
protected void onResume() {
  super.onResume();
  MyApplication.activityResumed();
}

@Override
protected void onPause() {
  super.onPause();
  MyApplication.activityPaused();
}

In your finish() method, you want to use isActivityVisible() to check if the activity is visible or not. There you can also check if the user has selected an option or not. Continue when both conditions are met.

The source also mentions two wrong solutions…so avoid doing that.

Source: stackoverflow