I am trying to implement a login system using the Android Studio LoginActivity template. On AppEngine, I try the two lines:
UserService userService = UserServiceFactory.getUserService();
User user = userService.getCurrentUser();
but the user is always null. How is it supposed to function and be implemented? I mean, does UserService class only work when integrating the Login with Google Accounts?
If yes, what is the best and smartest way for me to implement a customized login system?
Yes, UserService class only work when integrating the Login with Google Accounts (Gmail or Apps), and here is how you can handle that.
About the customized login system, there isn't a correct answer, you need to implement a system of API (login, register, reset password, ...) based on your needs. Surely you need a datastore entity which preserves the account information and the password for the login process.