public boolean onContextItemSelected(MenuItem item) {


   AdapterContextMenuInfo adaptercontextmenuinfo = (AdapterContextMenuInfo) item.getMenuInfo();

   switch (item.getItemId())
   {
       case R.id.delete_item: //" how do I fetch the key of the item selected from firebase database"

                              return true;

       default:
           return super.onContextItemSelected(item);
   }

'
nhpccompaints-4cb01
complaints
-LDPrDAGIhPXlyYEmWSL
 comp_body:
 "1"
 comp_sub:
 "1"
 complaintid:
 "-LDPrDAGIhPXlyYEmWSL"
 empid:
 "1"
 -LDPrFFKAiJW9NnlOLYO
 -LDPrGzxMOM4Yas1ereU'