How to hide a button on click in a flutter application?

Question

normal image

image after entering the mobile number

See in this image when a user clicks on the login button the login button should disappear and a text field will be there followed by a submit button.

I have the text field appearing on click of the login button, however I don't know how to disappear that login button once it is pressed.

import 'dart:async';
import 'dart:ffi';
import 'package:cloud_firestore/cloud_firestore.dart';
import 'package:firebase_auth/firebase_auth.dart';
import 'package:flutter/cupertino.dart';
import 'package:flutter/material.dart';
import '../widgets/landing_page.dart';
import '../screens/register.dart';
import 'package:google_sign_in/google_sign_in.dart';
import '../widgets/google_sign_in_btn.dart';
import '../widgets/reactive_refresh_indicator.dart';

// Each item on AuthStatus represents quite literally the status of the UI.
// On SOCIAL_AUTH only the GoogleSignInButton will be visible.
enum AuthStatus { SOCIAL_AUTH }

class AuthScreen extends StatefulWidget {
  @override
  _AuthScreenState createState() => _AuthScreenState();
}

// On _AuthScreenState we start by defining the tag that will be used for our logger, then the default status as SOCIAL_AUTH, which means we need to do Google's sign in and the GoogleSignInButton will be visible and interactive.
class _AuthScreenState extends State<AuthScreen> {
  String phoneNo;
  String smsCode;
  String verificationId;
  bool _smsCodeDisabled = true;
  bool isThere;
  bool isPresent;
  bool _canShowButton = false;

  final db = Firestore.instance;
 Firestore.instance.collection('transcriber_user_registeration').where('mobileno', isEqualTo: phoneNo)
  // .snapshots().listen(
  //       (data) { print("Inside phone number check : $data"); });
  //       // return phoneNumberCheck(phoneNo);

  // QuerySnapshot result =
  //       await Firestore.instance.collection('transcriber_user_registeration').getDocuments();
  //  var list = result.documents;
  // print("Before data loop");
  // list.forEach((data) => print(data));
  // print("After data loop");

  Future<void> phoneNumberCheck(String phoneNo) async {
    print("Start of the function");
    //bool registerState = false;
    //bool isPresent = false;
    Firestore.instance
        .collection("transcriber_user_registeration")
        .getDocuments()
        .then((QuerySnapshot snapshot) {
      snapshot.documents.forEach((f) async {
        if (isPresent = ('${f.data['mobileno']}' == phoneNo)) {
          print(isPresent);
          final PhoneCodeAutoRetrievalTimeout autoRetrieve = (String verId) {
            this.verificationId = verId;
          };
          final PhoneCodeSent smsCodeSent =
              (String verId, [int forceCodeResend]) {
            this.verificationId = verId;
            print("im in sms code dialog");
//          smsCodeDialog(context).then((value) {
//          print('Signed in');
//          });
            setState(() {
              this._smsCodeDisabled = false;
            });
          };
          final PhoneVerificationCompleted verifySuccess =
              (AuthCredential user) {
            print("verified");
          };

          final PhoneVerificationFailed verifyFailed =
              (AuthException exception) {
            print('${exception.message}');
          };

          await FirebaseAuth.instance.verifyPhoneNumber(
            phoneNumber: this.phoneNo,
            codeAutoRetrievalTimeout: autoRetrieve,
            codeSent: smsCodeSent,
            timeout: const Duration(seconds: 5),
            verificationCompleted: verifySuccess,
            verificationFailed: verifyFailed,
          );
        }
//        else {
//          _showMessage();
//        }
      });
    });
    //print("End of the function $isPresent");
  }

  Future<void> verifyPhone() async {
    // final PhoneCodeAutoRetrievalTimeout autoRetrieve = (String verId) {
    //   this.verificationId = verId;
    // };
    var tmp1 = phoneNo.toString();
    print('ref stsmt starts $tmp1');
    await phoneNumberCheck(phoneNo);
    print("After execution of the function $isPresent");
    print('bvnnn');

  }

  Future<bool> smsCodeDialog(BuildContext context) {
    return showDialog(
        context: context,
        barrierDismissible: false,
        builder: (BuildContext context) {
          return new AlertDialog(
            title: Text('Enter sms code'),
            content: TextField(onChanged: (value) {
              this.smsCode = value;
            }),
            contentPadding: EdgeInsets.all(10.0),
            actions: <Widget>[
              new FlatButton(
                  child: Text('Login'),
                  onPressed: () async {
                    //await signIn();
                    await FirebaseAuth.instance.currentUser().then((user) {
//                      Navigator.push(
//                          context,
//                          MaterialPageRoute(
//                              builder: (context) => LandingPageApp()));
                    });
                  })
            ],
          );
        });
  }

  signIn() {
    print("came to sign in page");
    final AuthCredential credential = PhoneAuthProvider.getCredential(
      verificationId: verificationId,
      smsCode: smsCode,
    );

    FirebaseAuth.instance.signInWithCredential(credential).then((user) {
      Navigator.push(
          context, MaterialPageRoute(builder: (context) => LandingPageApp()));
    }).catchError((e) {
      print(e);
    });
  }

  void hideWidget() {
    setState(() {
      _canShowButton != _canShowButton;
    });
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
        backgroundColor: Colors.white,
        body: Container(
          color: Colors.white,
          child: Column(
            mainAxisSize: MainAxisSize.min,
            mainAxisAlignment: MainAxisAlignment.start,
            children: <Widget>[
              Flexible(
                flex: 1,
                child: new Container(
                  //color: Colors.white,
                  height: 200.0,
                  width: 400.0,
                  decoration: new BoxDecoration(
                    image: DecorationImage(
                      image: new AssetImage('assets/images/download.png'),
                    ),
                  ),
                ),
              ),
              SizedBox(height: 20.0),
              Padding(
                padding: EdgeInsets.symmetric(vertical: 16.0, horizontal: 20.0),
                child: TextFormField(
                    decoration:
                    InputDecoration(hintText: 'Enter your Phone number'),
                    keyboardType: TextInputType.phone,
                    onChanged: (value) {
                      this.phoneNo = "+91$value";
                    },
                    validator: validateMobile),
              ),
              SizedBox(height: 10.0),
              Visibility(
                visible: _canShowButton,
                child: RaisedButton(
                  child: Text('Login'),
                  textColor: Colors.white,
                  elevation: 7.0,
                  color: Colors.blue,
                  onPressed: () async {
                    bool _canShowButton = true;
                    await verifyPhone();
                    setState(() {
                      _canShowButton = !_canShowButton;
                    });
                    hideWidget();
                    //_number();
                  },
                ),
              ),
              _smsCodeDisabled
                  ? SizedBox(height: 10.0)
                  : Column(
                mainAxisAlignment: MainAxisAlignment.start,
                children: <Widget>[
                  Padding(
                    padding: EdgeInsets.symmetric(
                        horizontal: 20.0, vertical: 16.0),
                    child: TextFormField(
                        decoration:
                        InputDecoration(hintText: 'Enter OTP'),
                        keyboardType: TextInputType.number,
                        onChanged: (value) {
                          this.smsCode = value;
                        },
                        validator: validateOtp),
                  ),
                  SizedBox(height: 10.0),
                  RaisedButton(
                    onPressed: () async {
                      await signIn();
                      FirebaseAuth.instance.currentUser().then((user) {
                        print(["user", user]);
                        if (user != null) {
                          print(user.uid);
//                                Navigator.of(context).pop();
////                                    Navigator.of(context).pushReplacementNamed('/homePage');
//                                Navigator.of(context).push(
//                                    MaterialPageRoute<Null>(
//                                        builder: (BuildContext context) {
//                                  return new LandingPageApp();
//                                }));
                        } else {
                          print("user is null");
                          Navigator.of(context).pop();
                          signIn();
                        }
                      });
                    },
                    child: Text('Submit'),
                    textColor: Colors.white,
                    elevation: 7.0,
                    color: Colors.blue,
                  ),
                ],
              ),
              SizedBox(
                height: 20.0,
              ),
              Column(
                children: <Widget>[
                  Row(children: <Widget>[
                    Padding(
                      padding: EdgeInsets.symmetric(
                          vertical: 16.0, horizontal: 20.0),
                      child: Text(
                        'Not a Registered User?',
                        style: TextStyle(
                          fontSize: 16,
                        ),
                      ),
                    ),
                    MaterialButton(
                      child: Text(
                        'Register',
                        style: TextStyle(
                          color: Colors.black,
                        ),
                      ),
                      //color: Colors.blue,
                      onPressed: () {
                        Navigator.push(
                            context,
                            MaterialPageRoute(
                                builder: (context) => Register()));
                      },
                    ),
                  ]),
                ],
              ),
            ],
          ),
        ));
  }
}

String validateMobile(String value) {
  //Indian Mobile numbers are of 10 digits only.
  if (value.length != 10)
    return 'Mobile number must be of 10 digits';
  else
    return null;
}

String validateOtp(String value) {
  //Otp needs to be of 6 digits
  if (value.length != 6)
    return 'OTP must be of 6 digits';
  else
    return null;
}

Answer 1

In your build method, you already have a boolean _smsCodeDisabled to identify whether the otp field need to show or not. You can use the same boolean to hide the login field and button. The logic should be something like:

@override
Widget build(BuildContext context) { 
    return _smsCodeDisabled ? _getLoginWidget() : _getOtpWidget();
}

Widget _getLoginWidget() {
   // Return Login field and button
}

Widget _getOtpWidget() {
  // Return otp field and button
}

Or If you need to only hide the login button, use the following logic:

@override
Widget build(BuildContext context) { 
    return Scaffold(
       // other code
       // Login button logic
      _smsCodeDisabled ? RaisedButton(...) : Container();
    );
}

Answer 2

Please try this

  bool _canShowButton = true;

  void hideWidget() {
    setState(() {
      _canShowButton = !_canShowButton;
    });
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('Test Screen'),
      ),
      body: Container(
          padding: const EdgeInsets.all(8),
          child: Column(
            children: <Widget>[
              Flexible(
                flex: 1,
                child: Container(
                  //color: Colors.white,
                  height: 200.0,
                  width: 400.0,
                  decoration: BoxDecoration(
                    image: DecorationImage(
                      image: AssetImage('https://picsum.photos/250?image=10'),
                    ),
                  ),
                ),
              ),
              SizedBox(height: 20.0),
              ///if the show button is false
              !_canShowButton
                  ? const SizedBox.shrink()
                  : RaisedButton(
                      child: Text('Login'),
                      textColor: Colors.white,
                      elevation: 7.0,
                      color: Colors.blue,
                      onPressed: () {
                        hideWidget();
                        //_number();
                      },
                    ),
            ],
          )),
    );
  }