FormController<TValue> class

Context for using the form.

How to use

First, initialize FormController with the values to be used in the form. In the example, Map is used, but it is safer to use an immutable class.

FormController should be saved using some state management method.

We will give key to the key of Form and place the FormXX widget under it.

Pass the value of FormController in the initialValue of each form widget, and describe the process of rewriting the value of FormController in the onSaved.

If the Submit button is pressed, validate is executed.

Each form's validate is executed. Only when true is returned from validate, onSaved of each form is executed and the process of rewriting value of FormController is executed.

After that, execute the process of writing data to the server based on the value of FormController, etc.

フォームを利用していくためのコンテキスト。

基本的な使い方

まず、FormControllerにフォーム中で利用するための値を与えながら初期化します。例ではMapが利用されてますが、immutableなクラスを利用したほうが安全です。

FormControllerはなにかしらの状態管理手法で保存してください。

Formのkeyにkeyを与え、その下にFormXXウィジェットを配置していきます。

それぞれのフォームウィジェットのinitialValueにFormControllerのvalueを渡し、onSavedにFormControllerのvalueを書き換える処理を記載します。

Submitボタンが押された場合、validateを実行します。

それぞれのフォームのvalidateが実行されます。validateからtrueが返された場合のみそれぞれのフォームのonSavedが実行され、FormControllerのvalueを書き換える処理が走ります。

その後、FormControllerのvalueを元にサーバーにデータを書き込む処理等を実行してください。

class FormPage extends StatefulWidget {
  const FormPage();

  State<StatefulWidget> createState() => _FormPageState();
}

class _FormPageState extends State<FormPage> {
  final _context = FormContext(<String, dynamic>{});

  @override
  Widget build(BuildContext context) {
    return Form(
      key: _context.key,
      child: Column(
        children: [
          FormTextField(
            hintText: "Input name",
            initialValue: _context.value["name"],
            onSaved: (value) => {...form.value, "name": value},
          ),
          FormTextField(
            hintText: "Input description",
            initialValue: _context.value["description"],
            onSaved: (value) => {...form.value, "description": value},
          ),
          FormButton(
            "Submit",
            onPressed: () {
              if(!_context.validate()){
                return;
              }
              // Form data storage process.
            }
          ),
        ]
      ),
    );
  }
}

Inheritance

Object
ChangeNotifier
ValueNotifier<TValue>
FormController

Available Extensions

Constructors

FormController(TValue value): Context for using the form.

Properties

hashCode → int: The hash code for this object.
no setterinherited
hasListeners → bool: Whether any listeners are currently registered.
no setterinherited
key → GlobalKey<FormState>: GlobalKey passed to Form.
final
runtimeType → Type: A representation of the runtime type of the object.
no setterinherited
value ↔ TValue: The current value stored in this notifier.
getter/setter pairinherited

Methods

addListener(VoidCallback listener) → void: Register a closure to be called when the object changes.
inherited
dispose() → void: Discards any resources used by the object. After this is called, the object is not in a usable state and should be discarded (calls to addListener will throw after the object is disposed).
inherited
noSuchMethod(Invocation invocation) → dynamic: Invoked when a nonexistent method or property is accessed.
inherited
notifyListeners() → void: Call all the registered listeners.
inherited
register(FormFieldState state) → void: Register FormFieldState to execute validator and onSaved when validate is executed.
removeListener(VoidCallback listener) → void: Remove a previously registered closure from the list of closures that are notified when the object changes.
inherited
toString() → String: A string representation of this object.
inherited
unregister(FormFieldState state) → void: Unregister FormFieldState.
validate({bool autoUnfocus = true}) → TValue?: Validate all forms placed under Form to which key is passed, and if there are no problems, onSaved is executed and the value is returned.
validateAndSave({bool autoUnfocus = true}) → bool: Validation is performed on all forms placed under Form to which key is passed, and if there are no problems, onSaved is executed.

Operators

operator ==(Object other) → bool: The equality operator.
inherited