ActivityManager activityManager = GetSystemService(Context.ACTIVITY_SERVICE) as ActivityManager;
            List<RunningAppProcessInfo> appProcesses = activityManager.getRunningAppProcesses();
            foreach(RunningAppProcessInfo appProcess in appProcesses){
                if(appProcess.importance == RunningAppProcessInfo.IMPORTANCE_FOREGROUND){
                    Log.i("Foreground App", appProcess.processName);
                    //SetNotification ();
                }
            }

ActivityManager activityManager = GetSystemService(Context.ACTIVITY_SERVICE) as ActivityManager;