public class AppStatusService extends Service {

    private static final String TAG = "AppStatusService";

    private ActivityManager activityManager;

    private String packageName; 

    @Override

    public IBinder onBind(Intent intent) {

        return null;

    } 

    @Override

    public int onStartCommand(Intent intent, int flags, int startId) {

        activityManager = (ActivityManager) this.getSystemService(Context.ACTIVITY_SERVICE);

        packageName = this.getPackageName();

        new Thread() {

            public void run() {

                try {

                    while (true) {

                        Thread.sleep(1000);

                        if (isAppOnForeground()) {

                            Log.i(TAG, "true");

                        } else {

                            Log.i(TAG, "false");

                        }

                    }

                } catch (Exception e) {

                    e.printStackTrace();

                }

            }

        }.start();

        return super.onStartCommand(intent, flags, startId);

    } 

    private boolean isAppOnForeground() {

        // Returns a list of application processes that are running on the device

        List<RunningAppProcessInfo> appProcesses = activityManager.getRunningAppProcesses();

        if (appProcesses == null) return false;

        for (RunningAppProcessInfo appProcess : appProcesses) {

            // importance:

            // The relative importance level that the system places

            // on this process.

            // May be one of IMPORTANCE_FOREGROUND, IMPORTANCE_VISIBLE,

            // IMPORTANCE_SERVICE, IMPORTANCE_BACKGROUND, or IMPORTANCE_EMPTY.

            // These constants are numbered so that "more important" values are

            // always smaller than "less important" values.

            // processName:

            // The name of the process that this object is associated with.

            if (appProcess.processName.equals(packageName)

                    && appProcess.importance == RunningAppProcessInfo.IMPORTANCE_FOREGROUND) {

                return true;

            }

        }

        return false;

    }

}