Monitoring Foreground Activity in Android

ActivityManager am = (ActivityManager) this.getSystemService(ACTIVITY_SERVICE);
List< ActivityManager.RunningTaskInfo > taskInfo = am.getRunningTasks(1); 
Log.d("topActivity", "CURRENT Activity ::"
            + taskInfo.get(0).topActivity.getClassName());
ComponentName componentInfo = taskInfo.get(0).topActivity;
componentInfo.getPackageName();

You will need the following permission:

<uses-permission android:name="android.permission.GET_TASKS"/>

source : http://stackoverflow.com/questions/17629053/how-do-android-monitor-usage-applications-work