DropdownButtonFormField<T> class Null safety

A FormField that contains a DropdownButton.

This is a convenience widget that wraps a DropdownButton widget in a FormField.

A Form ancestor is not required. The Form simply makes it easier to save, reset, or validate multiple fields at once. To use without a Form, pass a GlobalKey to the constructor and use GlobalKey.currentState to save or reset the form field.

See also:

Inheritance

Constructors

Creates a DropdownButton widget that is a FormField, wrapped in an InputDecorator.

Properties

autovalidateMode → AutovalidateMode
Used to enable/disable this form field auto validation and update its error text.
finalinherited
builder → FormFieldBuilder<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.
finalinherited
decoration → InputDecoration
The decoration to show around the dropdown button form field.
final
enabled → bool
Whether the form is able to receive user input.
finalinherited
hashCode → int
The hash code for this object.
nonVirtual">@nonVirtualread-onlyinherited
initialValue → T?
An optional value to initialize the form field to, or null otherwise.
finalinherited
key → Key?
Controls how one widget replaces another widget in the tree.
finalinherited
onChanged → ValueChanged<T?>?
Called when the user selects an item.
final
onSaved → FormFieldSetter<T>?
An optional method to call with the final value when the form is saved via FormState.save.
finalinherited
restorationId → String?
Restoration ID to save and restore the state of the form field.
finalinherited
runtimeType → Type
A representation of the runtime type of the object.
read-onlyinherited
validator → FormFieldValidator<T>?
An optional method that validates an input. Returns an error string to display if the input is invalid, or null otherwise.
finalinherited

Methods

createElement() → StatefulElement
Creates a StatefulElement to manage this widget's location in the tree.
inherited
createState() → FormFieldState<T>
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.
protected">@protectedinherited
debugFillProperties(DiagnosticPropertiesBuilder properties) → void
Add additional properties associated with the node.
inherited
noSuchMethod(Invocation invocation) → dynamic
Invoked when a non-existent 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.
nonVirtual">@nonVirtualinherited