When you rotate your Mobile or Tablet then you will notice that the App Relaunches. This happens because the Activity gets restarted and as a result the Fragment also gets restarted.
When this happens your App loses track of the data like the EmployeeId we pass to display Employee information.
To prevent this Android provides us with onSaveInstanceState method which can be used to store any local variable.
You need to override this method like
@Override
public void onSaveInstanceState(Bundle savedInstanceState){
savedInstanceState.putLong(“employeeIndex”, employeeIndex);
}
Follow the video to understand this better.
Source Code is available here
Why Android 