Flutter validator is not returning anything - validation

Question

it is my signup.dart file code:
it is nothing show somthing like a error.
But just i would like to see display an error under of textfield but it doesn't show anything.
Can anyone say what I'm doing wrongly?
import 'package:flutter/material.dart';
class SignupPage extends StatefulWidget {
#override
_SignupPageState createState() => _SignupPageState();
}
class _SignupPageState extends State<SignupPage> {
final formkey = new GlobalKey<FormState>();
registered() {
print("validation form...$formkey");
}
#override
Widget build(BuildContext context) {
return new Scaffold(
resizeToAvoidBottomPadding: false,
body: Column(crossAxisAlignment: CrossAxisAlignment.start, children: <
Widget>[
Container(
child: Stack(
children: <Widget>[
Container(
padding: EdgeInsets.fromLTRB(15.0, 110.0, 0.0, 0.0),
child: Text(
'Qeydiyyat',
style:
TextStyle(fontSize: 60.0, fontWeight: FontWeight.bold),
),
),
],
),
),
SizedBox(height: 30.0),
Container(
padding: EdgeInsets.only(top: 35.0, left: 20.0, right: 20.0),
child: Form(
key: formkey,
child: Column(
children: <Widget>[
TextFormField(
decoration: InputDecoration(
labelText: 'E-Poçt',
labelStyle: TextStyle(
fontFamily: 'Montserrat',
fontWeight: FontWeight.bold,
color: Colors.grey),
// hintText: 'EMAIL',
// hintStyle: ,
focusedBorder: UnderlineInputBorder(
borderSide: BorderSide(color: Colors.green))),
validator: (val) {
return "sea";
},
),
SizedBox(height: 10.0),
TextFormField(
keyboardType: TextInputType.text,
decoration: InputDecoration(
labelText: 'Şifrə ',
labelStyle: TextStyle(
fontFamily: 'Montserrat',
fontWeight: FontWeight.bold,
color: Colors.grey),
focusedBorder: UnderlineInputBorder(
borderSide: BorderSide(color: Colors.green))),
obscureText: true,
validator: (val) {
return "sea";
},
),
SizedBox(height: 10.0),
TextFormField(
decoration: InputDecoration(
labelText: 'Ad Soyad',
labelStyle: TextStyle(
fontFamily: 'Montserrat',
fontWeight: FontWeight.bold,
color: Colors.grey),
focusedBorder: UnderlineInputBorder(
borderSide: BorderSide(color: Colors.green))),
validator: (val) {
return "sea";
},
),
SizedBox(height: 50.0),
Container(
height: 40.0,
child: RaisedButton(
color: Colors.blue,
onPressed: registered,
shape: RoundedRectangleBorder(
side: BorderSide(color: Colors.blue),
borderRadius: BorderRadius.circular(50),
),
child: Center(
child: Text(
'Qeydiyyat',
style: TextStyle(
color: Colors.white,
fontWeight: FontWeight.bold,
fontFamily: 'Montserrat'),
),
),
)),
SizedBox(height: 20.0),
Container(
height: 40.0,
child: RaisedButton(
color: Colors.red,
disabledColor: Colors.transparent,
shape: RoundedRectangleBorder(
side: BorderSide(color: Colors.blue),
borderRadius: BorderRadius.circular(50),
),
child: InkWell(
onTap: () {
Navigator.of(context).pop();
},
child: Center(
child: Text('Daxil ol',
style: TextStyle(
color: Colors.blue,
fontWeight: FontWeight.bold,
fontFamily: 'Montserrat')),
),
),
),
),
],
),
)),
]));
}
}
it is nothing show somthing like a error.
But just i would like to see display an error under of textfield but it doesn't show anything.
Can anyone say what I'm doing wrongly?

Answer 1

if you want to validation work automatically set autoValidate property of TextField to true. otherwise, if you want to validate after an event such button clicks you can call validate() method. your register method can change to something like this:
registered() {
if (formKey.currentState.validate()) {
//do something
}
}