How to Check If Activity Is in Foreground or in Visible Background

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

Knowing if activity is running on foreground or background

Expanding on mco's answer, your GCMIntentService needs to do something that will trigger work in a foreground activity of yours, if you have a foreground activity. Typically, you will do this by setting up your activities to respond to some sort of message in onResume() and removing that in onPause().

"Some sort of message" could be:

• An Intent sent via LocalBroadcastManager
• An Intent sent via the classic sendBroadcast()
• A message via a message bus, like Otto
• Etc.

How to detect when an Android app goes to the background and come back to the foreground

The onPause() and onResume() methods are called when the application is brought to the background and into the foreground again. However, they are also called when the application is started for the first time and before it is killed. You can read more in Activity.

There isn't any direct approach to get the application status while in the background or foreground, but even I have faced this issue and found the solution with onWindowFocusChanged and onStop.

For more details check here Android: Solution to detect when an Android app goes to the background and come back to the foreground without getRunningTasks or getRunningAppProcesses.

How to detect if any of my activity is front-most and visible to user?

I don't know that there's a method to get the currently displayed activity, but you could do something combining the Activity Lifecycle and a flag.

For the flag, if you've extended the Application class, that's probably a decent place to store it. For extending the application class, the top answer to this question has info. (d).

So probably keep track of the current active activity (or a flag that the activity is visible) in onResume/onPause or onStart/onStop depending on exactly what behavior you want.

Since you have multiple activities, you'll need a centroid place for storing the flag, which is why the Application makes sense. You can get the custom Application object by casting the application context (e.g. ((MyApplication)getApplicationContext()).isMyActivityActive).

You could extend Activity as well to help keep this code clean and contained.

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If you're using a service you could bind to the service in every activity in the onStart/onStop (or onResume/onPause). If bound, you're visible.

Android: how do I check if activity is running?

You can use a static variable within the activity.

class MyActivity extends Activity {
     static boolean active = false;

      @Override
      public void onStart() {
         super.onStart();
         active = true;
      } 

      @Override
      public void onStop() {
         super.onStop();
         active = false;
      }
}

The only gotcha is that if you use it in two activities that link to each other then onStop on the first is sometimes called after onStart in second. So both might be true briefly.

Depending on what you are trying to do (update the current activity from a service?). You could just register a static listener in the service in your activity onStart method then the correct listener will be available when your service wants to update the UI.

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