Write an Android application

I need android code. Requirement: I have around 50 Activities in my App. When my app launches for the first time a dialogue should appear with two text fields and 1 button. This dialogue will appear only once when the app gets installed, user will not be able to cancel or skip this dialogue. User has only 1 option to enter PIN and save it. Dialogue will contain following UI components; TextField1: Enter PIN TextField2: Verify PIN Button: Save (When user clicks this button PIN should be saved in SharedPreferences) Once user saves the PIN than the app would be showing Any Activity. The App is in running state and user is interacting with it. If user is not interacting with the app for more than 1 minute than another dialogue should appear asking user to enter PIN to unlock application. This dialogue will be fixed too, means there is no way user can cancel or skip this. Once user enters PIN, it should verify it with the saved PIN (Which user entered first time). This process should be repeated every time. If user presses back button or closes the app and next time user starts the app it should again ask for PIN and until user is not entering the PIN it should stay as it is. So, I need a piece of code which I can use in all my 50 Activities because user could be on any of the Activities in the app. May be a Java class that I can extend in my all Activities..