FieldSelector<T> class
A widget that rebuilds whenever a selected value from a FieldController changes.
The FieldSelector is a specialized version of FormySelector that
observes a FieldController and rebuilds only when the selected
portion of the field state (defined by the selector) changes.
This is useful to optimize performance by avoiding rebuilds when unrelated parts of the field change.
Properties
- controller: The FieldController being observed.
- selector: Function that extracts the value to watch from the field.
- child: Builder that receives the selected value.
Example
FieldSelector<bool>(
controller: myField,
selector: (field) => field.valid,
child: (isValid) => Icon(
isValid ? Icons.check : Icons.close,
color: isValid ? Colors.green : Colors.red,
),
)
See also
- FieldController, which manages individual field state.
- FormySelector, the generic base class that this widget extends.
- Inheritance
-
- Object
- DiagnosticableTree
- Widget
- StatefulWidget
- FormySelector<
FieldController, T> - FieldSelector
Constructors
- FieldSelector.new({Key? key, required FieldController controller, required T selector(FieldController value), required Widget child(T value)})
-
Creates a FieldSelector.
const
Properties
- child → Widget Function(T value)
-
Builder function that receives the selected value.
finalinherited
- controller → FieldController
-
The controller being observed.
finalinherited
- hashCode → int
-
The hash code for this object.
no setterinherited
- key → Key?
-
Controls how one widget replaces another widget in the tree.
finalinherited
- runtimeType → Type
-
A representation of the runtime type of the object.
no setterinherited
- selector → T Function(FieldController value)
-
Function that selects the data to watch from the controller.
finalinherited
Methods
-
createElement(
) → StatefulElement -
Creates a StatefulElement to manage this widget's location in the tree.
inherited
-
createState(
) → State< FieldSelector< 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.
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, int wrapWidth = 65}) → 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