update Current Index
Update the current index selected by the user. This lastAdministrativeUnitHashCode property is used to compare if the contents of the current AdministrativeUnit really changed. If the user goes back to the administrative units screen and selects the same one again, it won't emit it again. To solve that problem, the lastAdministrativeUnitHashCode is reset each time this method is called.
Parameters
index
The new index value of the AdministrativeUnit the user selected on the screen.