How to increment a value on view holder variables in android?

Question

I have a viewholder in my Android app and I tried to set an incremented value on a textfield. I tried it like following,

Activity

Answer 1

You also need to set a tag for the Button, if you want to manipulate the holder item.

   if (convertView == null) {
        ...
        holder.buttonPlus = (ButtonRectangle) convertView.findViewById(R.id.buttonPlus);
        holder.buttonPlus.setTag(holder);
        holder.buttonPlus.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Holder current= (Holder) v.getTag();
                current.inc=current.inc+1;
                notifyDataSetChanged();
            }
        });
        convertView.setTag(holder);
    } else {
        holder = (Holder) convertView.getTag();
    }