Firebase authentication includes several ways to provide authentication to your apps. Among them, you find authentication with a username and password, or third-party providers such as Google, Microsoft, and others. In this recipe, you have created a screen that leverages Firebase authentication to provide login, logout, and signup features.
In order to leverage Firebase authentication, you need to enable the method or methods you want to use first, and you do that from the Firebase console: in the Build section of the console, you find the Sign in methods page. All authentication methods are disabled by default. So the first step you performed in this recipe was enabling the email/password authentication method. This provider allows you to sign up and log in with an email and a password.
Once the authentication method was enabled, you designed the user interface in login_screen.dart. There, you imported firebase_auth, which is the package used for the Firebase authentication...