Android : Save and Restore FragmentActivities in an ArrayList

I have a list containing ActivityA, each ActivityA has different values inside it, however they all have the same class (which is ActivityA). When the user navigates back to the list from an activity, I store that activity in an ArrayList and retrieve it and start it as an intent when the user clicks on the same activity in the list again. However, that causes it to be re-created. I want it to be resumed from the state it was stored in the ArrayList. How can I do this?

Thanks.