onVerifyButtonClick.dart

Future<void> _onVerifyButtonClick() async {
    showProgressBar(context, "Verifying OTP, Please Wait!");
    String otp = _otpController.text.trim();

    final AuthCredential credential = PhoneAuthProvider.getCredential(
      verificationId: _verificationId,
      smsCode: otp,
    );

    await _auth.signInWithCredential(credential).then((user) {
      _navigateToHome();
    }).catchError((error) {
      Navigator.pop(context);
      switch (error.code) {
        case 'ERROR_INVALID_VERIFICATION_CODE':
          showSnackBar(_scaffoldKey, 'Invalid OTP...');
          break;
        case 'ERROR_SESSION_EXPIRED':
          showSnackBar(_scaffoldKey, 'OTP Expired...');
          break;
        case 'ERROR_INVALID_CREDENTIAL':
          showSnackBar(_scaffoldKey, 'Invalid Credentials...');
          break;
        case 'ERROR_USER_DISABLED':
          showSnackBar(_scaffoldKey, 'User Disabled...');
          break;
      }
    });
  }