Flutter for Beginners

Sending verification code

The first stage of phone authentication is when the server (Firebase, in our case) sends a verification code through SMS to the phone number the user entered.

This is done by using the Firebase SDK method called verifyPhoneNumber, which requests the server to start a phone authentication as shown here:

// _sendVerificationCode method (LoginPageState) login_page.dartvoid _sendVerificationCode() async {  final PhoneCodeSent codeSent = (String verId, [int forceCodeResend]) {    _verificationId = verId;    _goToVerificationStep();  };  final PhoneVerificationCompleted verificationSuccess = (FirebaseUser user) {    _loggedIn();  };  final PhoneVerificationFailed verificationFail = (AuthException exception) {    goBackToFirstStep(); }; ...