Android: Identify listviewItem when checkbox of item is checked/unchecked

I got a listView with dynamically created items. Each item has a checkbox which can be checked/unchecked. When the checkbox is pressed this function is called:

public void updateClientList(View v) {
}

Now I want to change the specific item in my arraylist which is the base of the listview. But how do I know which checkbox was checked?

How can I do that? Thanks for your help!