Forms in Flutter
30 March, 2023
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In Flutter, a form is a widget that manages a form of user input. Forms are used to collect data from the user and validate that data. They can be used for tasks such as logging in, signing up, or placing an order.
There are several different types of form widgets in Flutter, including:
Form: A container for form fields that can validate input.TextFormField: A single line text input field that can validate input.CheckboxFormField: A checkbox that can validate input.RadioFormField: A radio button that can validate input.DropdownFormField: A dropdown menu that can validate input.
Here's an example of how you might use a Form and TextFormField in Flutter:
Form(
key: _formKey,
child: Column(
children: [
TextFormField(
validator: (value) {
if (value.isEmpty) {
return 'Please enter some text';
}
return null;
},
),
RaisedButton(
onPressed: () {
if (_formKey.currentState.validate()) {
// Process data.
}
},
child: Text('Submit'),
),
],
),
)
This example creates a form with a single text input field. The validator function is called when the user submits the form and returns an error message if the input is invalid. When the user clicks the submit button, the validate method is called on the form to validate all of the form fields. If the form is valid, the data can be processed. If the form is invalid, the error messages will be displayed to the user.
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