Whatsapp doesn't show login screen once registered

Question

Once you registered with the Whatsapp , even if you force close the app from App Manager or Kill its process, when you run it again it runs from the point (activity) where you left. How does that possible? An Android application shows the first activity which is also set as launcher activity, Is that possible that it saves some data in SQLite , some check or flag?

Answer 1

startupactivity.java is your launcher activity in manifest file.

In your startupactivity.java

1)how to check if already login or not?

->use sharedpreferences to check login or not(store and retrieve sharedpreferences)

->use file to store login data

->use sqlite database to store registration info.

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->check if already register then call homescreen.java

or

->if not registered then call registration.java