FormModifier class

An optional container for grouping together multiple form field widgets (e.g. TextField widgets).

Each individual form field should be wrapped in a FormField widget, with the Form widget as a common ancestor of all of those. Call methods on FormState to save, reset, or validate each FormField that is a descendant of this Form. To obtain the FormState, you may use Form.of with a context whose ancestor is the Form, or pass a GlobalKey to the Form constructor and call GlobalKey.currentState.

{@tool dartpad} This example shows a Form with one TextFormField to enter an email address and an ElevatedButton to submit the form. A GlobalKey is used here to identify the Form and validate input.

** See code in examples/api/lib/widgets/form/form.0.dart ** {@end-tool}

See also:

• GlobalKey, a key that is unique across the entire app.
• FormField, a single form field widget that maintains the current state.
• TextFormField, a convenience widget that wraps a TextField widget in a FormField.

Inheritance

• Object
• DiagnosticableTree
• Widget
• StatelessWidget
• SingleChildStatelessModifier
• FormModifier

Available extensions

• ModifierTransformer

Constructors

FormModifier({Key? key, Widget? child, Key? modifierKey, WillPopCallback? onWillPop, VoidCallback? onChanged, AutovalidateMode? autovalidateMode})

Creates a container for form fields.

const

Properties

autovalidateMode → AutovalidateMode?

Used to enable/disable form fields auto validation and update their error text.

final

hashCode → int

The hash code for this object.

no setter, inherited

key → Key?

Controls how one widget replaces another widget in the tree.

final, inherited

modifierKey → Key?

The actual key of the widget, which Modifier wrapped

final, inherited

onChanged → VoidCallback?

Called when one of the form fields changes.

final

onWillPop → WillPopCallback?

Enables the form to veto attempts by the user to dismiss the ModalRoute that contains the form.

final

runtimeType → Type

A representation of the runtime type of the object.

no setter, inherited

Methods

build(BuildContext context) → Widget

Describes the part of the user interface represented by this widget.

inherited

buildWithChild(BuildContext context, Widget? child) → Widget

A build method that receives an extra child parameter.

override

createElement() → SingleChildStatelessElement

Create a SingleChildStatelessElement

inherited

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

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

Operators

operator ==(Object other) → bool

The equality operator.

inherited