Application is in Forefround or background.

Here I write the code to know whether our application is in background or forground. We use Application.ActivityLifecycleCallbacks interface and know status in onActivityResumed() and onActivityPaused() method.

Just initialize it

 Foreground.init(getApplication()); 

Foreground.get().isForeground();

public class Foreground implements Application.ActivityLifecycleCallbacks {

public static final long CHECKING_DELAY = 500;
public static final String TAG = Foreground.class.getName();

public interface ListenerForeOrBAck {

    public void onBecameForeground();

    public void onBecameBackground();

}

private static Foreground instance;

private boolean foreground = false, paused = true;
private Handler handler = new Handler();
private List<ListenerForeOrBAck> listeners = new CopyOnWriteArrayList<ListenerForeOrBAck>();
private Runnable checking;


public static Foreground init(Application application){
    if (instance == null) {
        instance = new Foreground();
        application.registerActivityLifecycleCallbacks(instance);
    }
    return instance;
}

public static Foreground get(Application application){
    if (instance == null) {
        init(application);
    }
    return instance;
}

public static Foreground get(Context ctx){
    if (instance == null) {
        Context appCtx = ctx.getApplicationContext();
        if (appCtx instanceof Application) {
            init((Application)appCtx);
        }
        throw new IllegalStateException(
                "Foreground is not initialised and " +
                "cannot obtain the Application object");
    }
    return instance;
}

public static Foreground get(){
    if (instance == null) {
        throw new IllegalStateException(
                "Foreground is not initialised - invoke " +
                "at least once with parameterised init/get");
    }
    return instance;
}

public boolean isForeground(){
    return foreground;
}

public boolean isBackground(){
    return !foreground;
}

public void addListener(ListenerForeOrBAck listener){
    listeners.add(listener);
}

public void removeListener(ListenerForeOrBAck listener){
    listeners.remove(listener);
}

@Override
public void onActivityResumed(Activity activity) {
    paused = false;
    boolean wasBackground = !foreground;
    foreground = true;

    if (checking != null)
        handler.removeCallbacks(checking);

    if (wasBackground){
        Log.i(TAG, "went foreground");
        for (ListenerForeOrBAck lis : listeners) {
            try {
                lis.onBecameForeground();
            } catch (Exception e) {
                Log.e(TAG, "Listener  exception!", e);
            }
        }
    } else {
        Log.i(TAG, "still foreground");
    }
}

@Override
public void onActivityPaused(Activity activity) {
    paused = true;

    if (checking != null)
        handler.removeCallbacks(checking);

    handler.postDelayed(checking = new Runnable(){
        @Override
        public void run() {
            if (foreground && paused) {
                foreground = false;
                Log.i(TAG, "background");
                for (ListenerForeOrBAck l : listeners) {
                    try {
                        l.onBecameBackground();
                    } catch (Exception e) {
                        Log.e(TAG, "Listener  exception!", e);
                    }
                }
            } else {
                Log.i(TAG, "still foreground");
            }
        }
    }, CHECKING_DELAY);
}

@Override
public void onActivityCreated(Activity activity, Bundle savedInstanceState) {}

@Override
public void onActivityStarted(Activity activity) {}

@Override
public void onActivityStopped(Activity activity) {}

@Override
public void onActivitySaveInstanceState(Activity activity, Bundle outState) {}

@Override
public void onActivityDestroyed(Activity activity) {}
}