You should track the lastSelected position, and in listView's onItemClickListener deselect the lastSelected postion and select the current one.. something like this
ListView myListView = (ListView)findViewById(/* id of listView */);
ViewGroup lastSelected = null;
myListView.setOnItemClickListener(new onItemClickListener(
@Override
onItemClick(AdapterView arg0, View childView, int pos) {
if(lastSelected != null) {
lastSelected.setBackgroundDrawable(/*id of your unselected drawable*/);
}
lastSelected = (ViewGroup)childView;
lastSelected.setBackgroundDrawable(/*id of your selected drawable*/);
}
));