I have an app in which I have implemented login, logout and some customized actions. There are certain actions that can be performed only when user is logged in but if the user
Unfortunately there are no methods called when app is removed.
I'd prefer a solution where you log out the user when he quits the app and do a quiet login when he opens the app again without noticing that he was logged out. Therefore you need to store the credentials.
So you can ensure that the user is always logged out when he doesn't use the app.
But in my opinion you should change your backend so that it doesn't matter if the user has installed the app or not. But this may depend on your use case.