How to do Phone Authentication in Flutter using Firebase?

Question

I have searched many websites and I didn\'t find a way to implement phone authentication in Flutter using Firebase. Can anyone tell me how to this?

Answer 1

Below are the steps:-

1. Get OTP based on Phone Number:-

   void sendOTP(String phoneNumber, PhoneCodeSent codeSent,
         PhoneVerificationFailed verificationFailed) {
       if (!phoneNumber.contains('+')) phoneNumber = '+91' + phoneNumber;
       _firebaseAuth.verifyPhoneNumber(
           phoneNumber: phoneNumber,
           timeout: Duration(seconds: 30),
           verificationCompleted: null,
           verificationFailed: verificationFailed,
           codeSent: codeSent,
           codeAutoRetrievalTimeout: null);   }
   

2. Use the codeSent function to retrieve verification_id and pass it to OTP screen

   void codeSent(String verificationId, [int forceResendingToken]) {
   Navigator.push(
       context,
       MaterialPageRoute(
           builder: (context) => Otp(
                 phoneNumber: _phoneNumber,
                 verificationId: verificationId,
               )));
   }
   

3. Get user based on verification_id and OTP

   Future verifyOTP(String verificationId, String otp) async {
   AuthCredential credential = PhoneAuthProvider.getCredential(
     verificationId: verificationId,
     smsCode: otp,
   );
   AuthResult result;
   try {
     result = await _firebaseAuth.signInWithCredential(credential);
   } catch (e) {
     // throw e;
     return false;
   }
   print(result);
   (await result.user.getIdToken()).claims.forEach((k, v) {
     print('k= $k and v= $v');
   });
   if (result.user.uid != null) return true;
   return false;
   }
   

For more details watch the below video

https://youtu.be/e5M3EwJJYS4