title: Store data temporarily in a multiple activity app till the app is stopped?
body: <p>I have a RecyclerView (recycler1) which shows a list of users in my first activity. When you click on any item, a new activity is opened where you can chat with that user. The messages are shown yet in another RecyclerView (recycler2). But on clicking the back button, my recyclerview becomes empty. How can I store the messages for some time such that when I click on any users, the messages that I had with him while my app was active is shown? And I want the saved messages to be deleted if I kill my app i.e closed it completely?</p>