ReactiveNullable<T> class
A reactive widget that conditionally renders based on whether value is null or not.
When value is non-null, builder is used to build the widget using the value. When value is null, ifNull is rendered instead (defaults to Nothing).
This widget listens to a reactiveKey and rebuilds when notified via refresh or refreshOnly.
Example:
String? username;
ReactiveNullable<String>(
value: username,
builder: (name) => Text("Hello $name"),
ifNull: Text("Please login"),
)
// Later...
username = "Felipe";
refresh();
- Inheritance
-
- Object
- DiagnosticableTree
- Widget
- StatefulWidget
- ReactiveNullable
Constructors
- ReactiveNullable({Key? key, T? value, Widget ifNull = const Nothing(), required Widget builder(T), Key? reactiveKey})
- Creates a reactive widget that responds to nullability of a value.
Properties
- builder → Widget Function(T)
-
Builder that is called when value is non-null.
final
- hashCode → int
-
The hash code for this object.
no setterinherited
- ifNull → Widget
-
Widget shown when value is null.
final
- key → Key?
-
Controls how one widget replaces another widget in the tree.
finalinherited
- reactiveKey → Key
-
Key used to determine when to trigger rebuilds.
final
- runtimeType → Type
-
A representation of the runtime type of the object.
no setterinherited
- value → T?
-
The nullable value to evaluate at build time.
final
Methods
-
createElement(
) → StatefulElement -
Creates a StatefulElement to manage this widget's location in the tree.
inherited
-
createState(
) → State< ReactiveNullable> -
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