android - Custom Listener on Button click in ListView Item -

i have created custom listener interface button click in adapter class, followed tutorial: http://www.c-sharpcorner.com/uploadfile/9e8439/create-custom-listener-on-button-in-listitem-listview-in-a/

adapter:

        holder.btnqtyincrease.setonclicklistener(new onclicklistener() {              @override             public void onclick(view v) {                   if (customlistner != null) {                           customlistner.onbuttonclicklistner(position);                    }                    cart = cartarraylist.get(position);                 holder.textviewquantity.settag(cart);                  if(cart.getquantity() == 9) {                     toast.maketext(context, "already reached", toast.length_long).show();                     return ;                 }                 else                  {                                                                            cart.setquantity(cart.getquantity() + 1);                     holder.textviewquantity.settext(string.valueof(cart.getquantity()));                      totalprice = cart.getquantity() * cart.getprice();                      cartarraylist.cartarraylist.get(position).settotal(totalprice);                     holder.textviewtotal.settext(cart.gettotal());                 }              }         });          .....                return convertview;     } 

and have implemented listener in activity this:

public class cartactivity extends activity implements custombuttonlistener {         ......      @override     protected void oncreate(bundle savedinstancestate) {         super.oncreate(savedinstancestate);         log.d("cartactivity-oncreate", "oncreate");          setcontentview(r.layout.activity_cart);               ......                    }          @override     public void onresume()     {         super.onresume();            log.d("cartactivity-onresume", "onresume");                  }      @override     public void onbuttonclicklistner(int position) {          totalprice = cartarraylist.cartarraylist.get(position).getquantity() * cartarraylist.cartarraylist.get(position).getprice();            cartarraylist.cartarraylist.get(position).settotal(totalprice);          subtotal = subtotal + totalprice;     }  } 

as can see inside for loop setting , getting total of each , every list item, , calculating subtotal of arraylist items...

but whenever tap on btnqtyincrease makes change in total of list item price, not effect on subtotal amount

you should change logic in way it calculates subtotal in adapter , pass final value interface set in textview

so code should like:

holder.btnqtyincrease.setonclicklistener(new onclicklistener() {          @override         public void onclick(view v) {              cart = cartarraylist.get(position);             holder.textviewquantity.settag(cart);              if(cart.getquantity() == 9) {                 toast.maketext(context, "already reached", toast.length_long).show();                 return ;             }             else              {                                                                        cart.setquantity(cart.getquantity() + 1);                 holder.textviewquantity.settext(string.valueof(cart.getquantity()));                  totalprice = cart.getquantity() * cart.getprice();                  cartarraylist.cartarraylist.get(position).settotal(totalprice);                 holder.textviewtotal.settext(cart.gettotal());             }          }         // calculate total here          if (customlistner != null) {                   customlistner.onbuttonclicklistner(gettotalvalue());             }        }); 

define method gettotalvalue in adapter iterate through array , find subtotal value.

and set in textview

@override public void onbuttonclicklistner(float subtotal ) {         txtview.settext(string.valueof(subtotal)); } 

accordingly, change interface signature :

public void onbuttonclicklistner(float total);