FormField< T> class
A single form field.
This widget maintains the current state of the form field, so that updates and validation errors are visually reflected in the UI.
When used inside a Form, you can use methods on FormState to query or manipulate the form data as a whole. For example, calling FormState.save will invoke each FormField's onSaved callback in turn.
Use a GlobalKey with FormField if you want to retrieve its current state, for example if you want one form field to depend on another.
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
- Implementers
Constructors
-
FormField({Key key, @required FormFieldBuilder<
T> builder, FormFieldSetter< T> onSaved, FormFieldValidator< T> validator, T initialValue, bool autovalidate: false, bool enabled: true }) -
Creates a single form field. [...]
const
Properties
- autovalidate → bool
-
If true, this form field will validate and update its error text
immediately after every change. Otherwise, you must call
FormFieldState.validate to validate. If part of a Form that
autovalidates, this value will be ignored.
final
-
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.
final
- enabled → bool
-
Whether the form is able to receive user input. [...]
final
- initialValue → T
-
An optional value to initialize the form field to, or null otherwise.
final
-
onSaved
→ FormFieldSetter<
T> -
An optional method to call with the final value when the form is saved via
FormState.save.
final
-
validator
→ FormFieldValidator<
T> -
An optional method that validates an input. Returns an error string to
display if the input is invalid, or null otherwise. [...]
final
- hashCode → int
-
The hash code for this object. [...]
read-only, inherited
- key → Key
-
Controls how one widget replaces another widget in the tree. [...]
final, inherited
- runtimeType → Type
-
A representation of the runtime type of the object.
read-only, inherited
Methods
-
createState(
) → FormFieldState< T> -
Creates the mutable state for this widget at a given location in the tree. [...]
override
-
createElement(
) → StatefulElement -
Creates a StatefulElement to manage this widget's location in the tree. [...]
inherited
-
debugDescribeChildren(
) → List< DiagnosticsNode> -
Returns a list of DiagnosticsNode objects describing this node's
children. [...]
@protected, inherited
-
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 toStringDeep. [...]
inherited
-
toString(
{DiagnosticLevel minLevel: DiagnosticLevel.debug }) → String -
Returns 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 ==(
dynamic other) → bool -
The equality operator. [...]
inherited