EasyCustomFormField<T, C extends ValueNotifier> class

An extensible base class for wrapping form fields.

It is used as a base class for creating fields of custom types, as well as for creating a custom field on the fly in the widget tree.

For a custom field type, you must specify two general types: the first T is the field value type, and the second C is the controller type.

When a controller is specified, its Controller.value defines the initialValue. If this EasyCustomFormField is part of a scrolling container that lazily constructs its children, like a ListView or a CustomScrollView, then a controller should be specified. The controller's lifetime should be managed by a stateful widget ancestor of the scrolling container.

If a controller is not specified, initialValue can be used to give the automatically generated controller an initial value.

Remember to call Controller.dispose of the Controller when it is no longer needed. This will ensure we discard any resources used by the object.

Creates a EasyCustomFormField with an custom field and controller.

EasyCustomFormField<Color, ColorFieldController>(
  name: 'color',
  initialValue: Colors.teal,
  controllerBuilder: (value) => ColorFieldController(value),
  builder: (fieldState, onChangedHandler) => ColorField(
    controller: fieldState.controller,
    onChange: onChangedHandler,
  ),
)

Creates a TextField on the fly.

EasyCustomFormField<String, TextEditingController>(
  name: 'first_name',
  initialValue: 'some text',
  controllerBuilder: (value) => TextEditingController(text: value),
  controllerRebuilder: (oldController) => TextEditingController.fromValue(oldController.value),
  valueGet: (controller) => controller.text,
  valueSet: (controller, newText) => controller.text = newText,
  builder: (fieldState, onChangedHandler) => TextField(
    controller: fieldState.controller,
    focusNode: fieldState.focusNode,
    decoration: InputDecoration(
      errorText: fieldState.errorText,
    ),
    onChanged: onChangedHandler,
  ),
  validator: (value) => value.isEmpty ? 'Field is required.' : null,
),

See also:

• material.io/design/components/text-fields.html
• TextField, which is the underlying text field without the Form integration.
• Learn how to use a Controller in one of our cookbook recipes.

Inheritance

• Object
• DiagnosticableTree
• Widget
• StatefulWidget
• EasyFormField<T?>
• EasyCustomFormField

Implementers

• EasyTextFormField

Constructors

EasyCustomFormField({Key? key, required String name, C? controller, FocusNode? focusNode, T? initialValue, required CreateControllerCallback<C, T?> controllerBuilder, RecreateControllerCallback<C>? controllerRebuilder, ValueOfGetter<T?, C>? valueGet, ValueOfSetter<T?, C>? valueSet, required EasyFormCustomFieldBuilder<T, C> builder, ValueChanged<T>? onChanged, FormFieldSetter<T>? onSaved, EasyFormFieldValidator<T?>? validator, bool enabled = true, EasyAutovalidateMode autovalidateMode = EasyAutovalidateMode.disabled})

Creates a EasyCustomFormField that contains a custom field.

Properties

autovalidateMode → EasyAutovalidateMode

Used to enable/disable this form field auto validation and update its error text.

final, inherited

builder → EasyFormFieldBuilder<T?>

Function that returns the widget representing this form field. It is passed the form field state as input, containing the current value and validation state of this field.

final, inherited

controller → C?

Controls the value being edited.

final

controllerBuilder → CreateControllerCallback<C, T?>

A builder that instantiates a controller of type C for a value of type T.

final

controllerRebuilder → RecreateControllerCallback<C>?

A builder that recreates a controller from an old controller, if not specified, the controllerBuilder builder will be used.

final

enabled → bool

Whether the form is able to receive user input.

final, inherited

focusNode → FocusNode?

Focus node.

final, inherited

hashCode → int

The hash code for this object.

no setter, inherited

initialValue → T?

An optional value to initialize the form field to, or null otherwise.

final, inherited

key → Key?

Controls how one widget replaces another widget in the tree.

final, inherited

name → String

Name of the field.

final, inherited

onSaved → EasyFormFieldSetter<T?>?

An optional method to call with the final value when the form is saved via EasyFormState.save.

final, inherited

runtimeType → Type

A representation of the runtime type of the object.

no setter, inherited

validator → EasyFormFieldValidator<T?>?

An optional method that validates an input. Returns an error string to display if the input is invalid, or null otherwise.

final, inherited

valueGet → ValueOfGetter<T?, C>?

Callback to get the value from the controller, if not set then the controller's value property is used.

final

valueSet → ValueOfSetter<T?, C>?

Callback to set controller value, if not set - controller's value property is used.

final

Methods

createController(T value) → C

A builder that instantiates a controller of type C for a value of type T.

createElement() → StatefulElement

Creates a StatefulElement to manage this widget's location in the tree.

inherited

createState() → _EasyCustomFormFieldState<T, C>

Creates the mutable state for this widget at a given location in the tree.

override

debugDescribeChildren() → List<DiagnosticsNode>

Returns a list of DiagnosticsNode objects describing this node's children.

inherited

debugFillProperties(DiagnosticPropertiesBuilder properties) → void

Add additional properties associated with the node.

inherited

noSuchMethod(Invocation invocation) → dynamic

Invoked when a nonexistent method or property is accessed.

inherited

recreateController(C oldController) → C

A builder that recreates a controller from an old controller.

setValue(C controller, T? value) → dynamic

Setter, to set the controller value.

toDiagnosticsNode({String? name, DiagnosticsTreeStyle? style}) → DiagnosticsNode

Returns a debug representation of the object that is used by debugging tools and by DiagnosticsNode.toStringDeep.

inherited

toString({DiagnosticLevel minLevel = DiagnosticLevel.info}) → String

A string representation of this object.

inherited

toStringDeep({String prefixLineOne = '', String? prefixOtherLines, DiagnosticLevel minLevel = DiagnosticLevel.debug}) → String

Returns a string representation of this node and its descendants.

inherited

toStringShallow({String joiner = ', ', DiagnosticLevel minLevel = DiagnosticLevel.debug}) → String

Returns a one-line detailed description of the object.

inherited

toStringShort() → String

A short, textual description of this widget.

inherited

valueOf(C controller) → T?

Getter, to get the value from the controller.

Operators

operator ==(Object other) → bool

The equality operator.

inherited