create a validator in flutter
TextFormField(
// The validator receives the text that the user has entered.
validator: (value) {
if (value.isEmpty) {
return 'Please enter some text';
}
return null;
},
);create a validator in flutter
TextFormField(
// The validator receives the text that the user has entered.
validator: (value) {
if (value.isEmpty) {
return 'Please enter some text';
}
return null;
},
);create a validator in flutter
ElevatedButton(
onPressed: () {
// Validate returns true if the form is valid, otherwise false.
if (_formKey.currentState.validate()) {
// If the form is valid, display a snackbar. In the real world,
// you'd often call a server or save the information in a database.
Scaffold
.of(context)
.showSnackBar(SnackBar(content: Text('Processing Data')));
}
},
child: Text('Submit'),
);validator flutter
final passwordValidator = MultiValidator([
RequiredValidator(errorText: 'password is required'),
MinLengthValidator(8, errorText: 'password must be at least 8 digits long'),
PatternValidator(r'(?=.*?[#?!@$%^&*-])', errorText: 'passwords must have at least one special character')
]);
String password;
Form(
key: _formKey,
child: Column(children: [
TextFormField(
obscureText: true,
onChanged: (val) => password = val,
// assign the the multi validator to the TextFormField validator
validator: passwordValidator,
),
// using the match validator to confirm password
TextFormField(
validator: (val) => MatchValidator(errorText: 'passwords do not match').validateMatch(val, password),
)
]),
);create a validator in flutter
// Define a custom Form widget.
class MyCustomForm extends StatefulWidget {
@override
MyCustomFormState createState() {
return MyCustomFormState();
}
}
// Define a corresponding State class.
// This class holds data related to the form.
class MyCustomFormState extends State<MyCustomForm> {
// Create a global key that uniquely identifies the Form widget
// and allows validation of the form.
//
// Note: This is a `GlobalKey<FormState>`,
// not a GlobalKey<MyCustomFormState>.
final _formKey = GlobalKey<FormState>();
@override
Widget build(BuildContext context) {
// Build a Form widget using the _formKey created above.
return Form(
key: _formKey,
child: Column(
children: <Widget>[
// Add TextFormFields and ElevatedButton here.
]
)
);
}
}Copyright © 2021 Codeinu
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