How to 'setstate' an element from one AlertDialog - flutter

Question

I made two forms with pass fields on both, then made all the code to, when the user clicks in the eye Icon, the field show the password, clicking again it hide the password.
But now I put these forms inside an Alert Dialog widget and now it doesn't updating when I click in the icon, only updates if I close the dialog and open again (you open the dialog, click in the icon, it doesn't change. If you close and open again you see the icon changed)
After some search I tried Stateful Builder but it doesn't work too.
Dialog:
Future<void> _myDialog(child){
return showDialog<void>(
context: context,
builder: (BuildContext context) {
return SingleChildScrollView(
child: AlertDialog(
content: StatefulBuilder(
builder: (BuildContext context, StateSetter setState) {
return Padding(
padding: EdgeInsets.all(20),
child: child,
);
},
),
insetPadding: EdgeInsets.only(left: 10, right: 10),
),
);
}
);
}
Toggle method referenced in my textFields:
void _toggle(int index) {
setState(() {
_toggleList[index] = !_toggleList[index];
});
}
How can I toggle it instantly when the user click in the icon as outside the alert?
Edit
Row _showButtons(){
return Row(
children: [
RaisedButton(
child: Text("Change email"),
onPressed: () {_myDialog(_showEmailFields());}
),
RaisedButton(
child: Text("Change pass"),
onPressed: () {_myDialog(_showPassFields());}
),
],
);
}

Answer 1

I have created a structure for you that you should use for achieving what you want here. Make your forms into a separate stateful widgets, so that they have their own State, and you call the right setState function. Right now the setState function you are calling does not belongs to the state of your alert dialog.
class Test extends StatefulWidget {
#override
State<StatefulWidget> createState() => _TestState();
}
class _TestState extends State<Test> {
void showForm() {
showDialog(
context: context,
builder: (context) {
return AlertDialog(
title: Text("Login"),
content: LoginWidget(),
);
},
);
}
#override
Widget build(BuildContext context) {
TextTheme textTheme = Theme.of(context).textTheme;
return Scaffold(
appBar: AppBar(
title: Text("Appbar"),
),
body: Center(
child: RaisedButton(
child: Text("Show Form"),
onPressed: showForm,
),
),
);
}
}
class LoginWidget extends StatefulWidget {
LoginWidget({Key key}) : super(key: key);
#override
LoginWidgetState createState() => LoginWidgetState();
}
class LoginWidgetState extends State<LoginWidget> {
GlobalKey<FormState> _formKey;
bool _passwordVisible;
#override
void initState() {
super.initState();
_formKey = GlobalKey<FormState>();
_passwordVisible = false;
}
#override
Widget build(BuildContext context) {
return Form(
key: _formKey,
child: Column(
children: [
TextFormField(
decoration: InputDecoration(labelText: "Email"),
),
SizedBox(
height: 10,
),
TextFormField(
obscureText: !_passwordVisible,
decoration: InputDecoration(
labelText: "Password",
suffixIcon: IconButton(
onPressed: () {
setState(() {
_passwordVisible = !_passwordVisible;
});
},
icon: Icon(
_passwordVisible ? Icons.visibility : Icons.visibility_off),
),
),
),
],
),
);
}
}