Storing data in a changing listfragment

I have a list fragment where each item contains a checkbox, and the user is able to check and uncheck it. Each item in the list fragment corresponds to an object in the class Task, which stores information on whether the checkbox is checked or not.

My question is, how do I modify the Task object in response to the checking and unchecking of the checkbox? I know that you usually create a Task object and then notify the adapter so that the UI changes in response, but how do you reverse the process?