ScaffoldMessenger class
Manages SnackBars and MaterialBanners for descendant Scaffolds.
This class provides APIs for showing snack bars and material banners at the bottom and top of the screen, respectively.
To display one of these notifications, obtain the ScaffoldMessengerState for the current BuildContext via ScaffoldMessenger.of and use the ScaffoldMessengerState.showSnackBar or the ScaffoldMessengerState.showMaterialBanner functions.
When the ScaffoldMessenger has nested Scaffold descendants, the ScaffoldMessenger will only present the notification to the root Scaffold of the subtree of Scaffolds. In order to show notifications for the inner, nested Scaffolds, set a new scope by instantiating a new ScaffoldMessenger in between the levels of nesting.
To create a local project with this code sample, run:
flutter create --sample=material.ScaffoldMessenger.1 mysample
See also:
- SnackBar, which is a temporary notification typically shown near the bottom of the app using the ScaffoldMessengerState.showSnackBar method.
- MaterialBanner, which is a temporary notification typically shown at the top of the app using the ScaffoldMessengerState.showMaterialBanner method.
- debugCheckHasScaffoldMessenger, which asserts that the given context has a ScaffoldMessenger ancestor.
- Cookbook: Display a SnackBar
- Inheritance
-
- Object
- DiagnosticableTree
- Widget
- StatefulWidget
- ScaffoldMessenger
Constructors
- ScaffoldMessenger({Key? key, required Widget child})
-
Creates a widget that manages SnackBars for Scaffold descendants.
const
Properties
- child → Widget
-
The widget below this widget in the tree.
final
- 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
Methods
-
createElement(
) → StatefulElement -
Creates a StatefulElement to manage this widget's location in the tree.
inherited
-
createState(
) → ScaffoldMessengerState -
Creates the mutable state for this widget at a given location in the tree.
override
-
debugDescribeChildren(
) → List< DiagnosticsNode> -
Returns a list of
DiagnosticsNodeobjects 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
Static Methods
-
maybeOf(
BuildContext context) → ScaffoldMessengerState? - The state from the closest instance of this class that encloses the given context, if any.
-
of(
BuildContext context) → ScaffoldMessengerState - The state from the closest instance of this class that encloses the given context.