How to access the function of the main activity from the ListAdapter?

Question

Java

Big brothers please tell a beginner andorid developer, I am using a ListView with an ArrayAdapter installed as a way to display data.
In the layout line that the adapter uses, 2 buttons "+1" and "-1" are set, which change the number in their own line.
The buttons work fine, but in the main form I want to calculate the total for all rows of the ArrayList.
Button press listeners are located in the adapter class. I can't find how I can update the total after clicking a button in a row.
I tried to do in main activity:
productList.setOnItemClickListener(new AdapterView.OnItemClickListener() { @Override public void onItemClick(AdapterView<?> adapter, View v, int position, long arg3) { SetSumAsTitle(); } });
But the event doesn't fire.

Answer 1

The general idea is this - the adapter should not steer it.
Process click events in the logic layer, change the model (list) and update the display in the view.