TextFormField Validation Not Working Correctly - flutter

Question

I am new to Flutter development, and I'm currently working on the sign in screen for my first full application. I apologize if this has already been asked, but I cannot figure out where my code is going wrong. I'm attempting to test basic form validation, just checking whether anything has been written into the form fields before I continue.
The code for my form is as follows:
class SignInForm extends StatefulWidget {
const SignInForm({super.key});
#override
SignInFormState createState() {
return SignInFormState();
}
}
class SignInFormState extends State<SignInForm> {
final _signInFormKey = GlobalKey<FormState>();
#override
Widget build(BuildContext context) {
return Form(
child: Column(
crossAxisAlignment: CrossAxisAlignment.center,
mainAxisAlignment: MainAxisAlignment.center,
children: <Widget>[
TextFormField(
decoration: const InputDecoration(
border: OutlineInputBorder(),
hintText: 'Username',
),
validator: (String? value) {
if (value == null || value.isEmpty) {
return 'Please enter a valid username';
}
return null;
},
),
Padding(
padding: EdgeInsets.only(top: 20),
child: TextFormField(
obscureText: true,
enableSuggestions: false,
autocorrect: false,
decoration: const InputDecoration(
border: OutlineInputBorder(),
hintText: 'Password',
),
validator: (String? value) {
if (value == null || value.isEmpty) {
return 'Please enter a valid password';
}
return null;
},
),
),
Container(
child: Row(
mainAxisAlignment: MainAxisAlignment.end,
children: [
TextButton(
style: ButtonStyle(
foregroundColor: MaterialStateProperty.all<Color>(Color(0xFF0b2240)),
),
onPressed: () {
if (_signInFormKey.currentState!.validate()) {
ScaffoldMessenger.of(context).showSnackBar(
const SnackBar(content: Text('Processing Data')),
);
}
},
child: const Text('Log In'),
),
],
),
),
Container(
child: Row(
mainAxisAlignment: MainAxisAlignment.end,
children: [
TextButton(
style: ButtonStyle(
foregroundColor: MaterialStateProperty.all<Color>(Color(0xFF0b2240)),
),
onPressed: () {
if (_signInFormKey.currentState!.validate()) {
ScaffoldMessenger.of(context).showSnackBar(
const SnackBar(content: Text('Processing Data')),
);
}
},
child: const Text('+ Sign Up'),
),
],
),
),
],
),
);
}
}
Thanks in advance for any help improving my code!

Answer 1

Your forgot the key for the form widget, that's why validation don't work.
#override
Widget build(BuildContext context) {
return Form(
key: _signInFormKey,
child: Column(
...
More infos here : https://docs.flutter.dev/cookbook/forms/validation