Comment afficher / masquer le mot de passe dans Flutter?

J'ai créé un écran de connexion pour mon application mais dans le champ du mot de passe, je veux une fonctionnalité comme lorsque je saisis un mot de passe au format * et à droite une icône lorsque l'utilisateur clique dessus, le mot de passe sera visible, j'ai créé un code pour mais quand je clique sur le champ de mot de passe, cette icône devient invisible et lorsque le champ de mot de passe perd le focus que l'icône réapparaît, alors comment toujours afficher cette icône, même le champ de mot de passe est au point? J'ai fourni un instantané pour comprendre facilement le problème.

Voici mon code d'écran de connexion ...

import 'package:flutter/material.dart';
import 'package:email_validator/email_validator.dart';
import 'package:secret_keeper/screens/home_screen/Home.dart';
import 'package:secret_keeper/screens/home_screen/passwords/PasswordsNavigation.dart';
import 'package:secret_keeper/screens/signup_page/SignupPage.dart';

class LoginPage extends StatefulWidget{
  @override
  _LoginPageState createState() => _LoginPageState();
}

class _LoginPageState extends State<LoginPage> {

  String _emailID, _password = "",_email = "abc@gmail.com", _pass = "Try.t.r.y@1";
  bool _obscureText = true;
  final _formKey = GlobalKey<FormState>();
  
  void _toggle(){
    setState(() {
      _obscureText = !_obscureText;
    });
  }

  void validateLogin(){
    if(_formKey.currentState.validate()){
      _formKey.currentState.save();
      if(_emailID == _email && _password == _pass){
        Navigator.pushReplacement(context, MaterialPageRoute(builder: (context) => Home()));
      }
    }
  }

  Widget emailInput(){
    return TextFormField(
      keyboardType: TextInputType.emailAddress,
      decoration: InputDecoration(
        labelText: "Email ID",
        labelStyle: TextStyle(fontSize: 14,color: Colors.grey.shade400),
        enabledBorder: OutlineInputBorder(
          borderRadius: BorderRadius.circular(10),
          borderSide: BorderSide(
            color: Colors.grey.shade300,
          ),
        ),
        focusedBorder: OutlineInputBorder(
            borderRadius: BorderRadius.circular(10),
            borderSide: BorderSide(
              color: Colors.red,
            )
        ),
      ),
      validator: (email) {
        if (email.isEmpty)
          return 'Please Enter email ID';
        else if (!EmailValidator.validate(email))
          return 'Enter valid email address';
        else
          return null;
      },
      onSaved: (email)=> _emailID = email,
      textInputAction: TextInputAction.next,
    );
  }

  Widget passInput(){
    return TextFormField(
      keyboardType: TextInputType.text,
      decoration: InputDecoration(
        labelText: "Password",
        labelStyle: TextStyle(fontSize: 14,color: Colors.grey.shade400),
        enabledBorder: OutlineInputBorder(
          borderRadius: BorderRadius.circular(10),
          borderSide: BorderSide(
            color: Colors.grey.shade300,
          ),
        ),
        focusedBorder: OutlineInputBorder(
          borderRadius: BorderRadius.circular(10),
          borderSide: BorderSide(
            color: Colors.red,
          )
        ),
        suffixIcon: IconButton(
          icon: Icon(
            _obscureText ? Icons.visibility : Icons.visibility_off,
          ),
          onPressed: _toggle,
        ),
      ),
      validator: (password){
        Pattern pattern =
            r'^(?=.*?[A-Z])(?=.*?[a-z])(?=.*?[0-9])(?=.*?[!@#\$&*~]).{8,}$';
        RegExp regex = new RegExp(pattern);
        if (password.isEmpty){
          return 'Please Enter Password';
        }else if (!regex.hasMatch(password))
          return 'Enter valid password';
        else
          return null;
      },
      onSaved: (password)=> _password = password,
      textInputAction: TextInputAction.done,
      obscureText: _obscureText,
    );
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      resizeToAvoidBottomPadding: false,
      backgroundColor: Colors.white,
      body: SafeArea(
        child: Container(
          padding: EdgeInsets.only(left: 16,right: 16),
          child: Form(
            key: _formKey,
            child: Column(
              mainAxisAlignment: MainAxisAlignment.spaceBetween,
              crossAxisAlignment: CrossAxisAlignment.start,
              children: <Widget>[
                Column(
                  crossAxisAlignment: CrossAxisAlignment.start,
                  children: <Widget>[
                    SizedBox(height: 50,),
                    Text("Welcome,",style: TextStyle(fontSize: 26,fontWeight: FontWeight.bold),),
                    SizedBox(height: 6,),
                    Text("Sign in to continue!",style: TextStyle(fontSize: 20,color: Colors.grey.shade400),),
                  ],
                ),
                Column(
                  children: <Widget>[
                    emailInput(),
                    SizedBox(height: 16,),
                    passInput(),
                    SizedBox(height: 12,),
                    Align(
                      alignment: Alignment.topRight,
                      child: Text("Forgot Password ?",style: TextStyle(fontSize: 14,fontWeight: FontWeight.w600),),
                    ),
                    SizedBox(height: 30,),
                    Container(
                      height: 50,
                      width: double.infinity,
                      child: FlatButton(
                        onPressed: validateLogin,
                        padding: EdgeInsets.all(0),
                        child: Ink(
                          decoration: BoxDecoration(
                            borderRadius: BorderRadius.circular(6),
                            gradient: LinearGradient(
                              begin: Alignment.centerLeft,
                              end: Alignment.centerRight,
                              colors: [
                                Color(0xffff5f6d),
                                Color(0xffff5f6d),
                                Color(0xffffc371),
                              ],
                            ),
                          ),
                          child: Container(
                            alignment: Alignment.center,
                            constraints: BoxConstraints(maxWidth: double.infinity,minHeight: 50),
                            child: Text("Login",style: TextStyle(color: Colors.white,fontWeight: FontWeight.bold),textAlign: TextAlign.center,),
                          ),
                        ),
                        shape: RoundedRectangleBorder(
                          borderRadius: BorderRadius.circular(6),
                        ),
                      ),
                    ),
                    SizedBox(height: 16,),
                    Container(
                      height: 50,
                      width: double.infinity,
                      child: FlatButton(
                        onPressed: (){},
                        color: Colors.indigo.shade50,
                        shape: RoundedRectangleBorder(
                          borderRadius: BorderRadius.circular(6),
                        ),
                        child: Row(
                          mainAxisAlignment: MainAxisAlignment.center,
                          children: <Widget>[
                            Image.asset("assets/images/facebook.png",height: 18,width: 18,),
                            SizedBox(width: 10,),
                            Text("Connect with Facebook",style: TextStyle(color: Colors.indigo,fontWeight: FontWeight.bold),),
                          ],
                        ),
                      ),
                    ),
                    SizedBox(height: 16,),
                    Container(
                      height: 50,
                      width: double.infinity,
                      child: FlatButton(
                        onPressed: (){},
                        color: Colors.indigo.shade50,
                        shape: RoundedRectangleBorder(
                          borderRadius: BorderRadius.circular(6),
                        ),
                        child: Row(
                          mainAxisAlignment: MainAxisAlignment.center,
                          children: <Widget>[
                            Image.asset("assets/images/facebook.png",height: 18,width: 18,),
                            SizedBox(width: 10,),
                            Text("Connect with Facebook",style: TextStyle(color: Colors.indigo,fontWeight: FontWeight.bold),),
                          ],
                        ),
                      ),
                    ),
                  ],
                ),
                Padding(
                  padding: EdgeInsets.only(bottom: 10),
                  child: Row(
                    mainAxisAlignment: MainAxisAlignment.center,
                    children: <Widget>[
                      Text("Don't have an account?",style: TextStyle(fontWeight: FontWeight.bold),),
                      SizedBox(width: 5,),
                      GestureDetector(
                        onTap: (){
                          Navigator.push(context, MaterialPageRoute(builder: (context){
                            return SignupPage();
                          }));
                        },
                        child: Text("Sign up",style: TextStyle(fontWeight: FontWeight.bold,color: Colors.red),),
                      )
                    ],
                  ),
                )
              ],
            ),
          ),
        ),
      ),
    );
  }
}