Overlay class Null safety

A stack of entries that can be managed independently.

Overlays let independent child widgets "float" visual elements on top of other widgets by inserting them into the overlay's stack. The overlay lets each of these widgets manage their participation in the overlay using OverlayEntry objects.

Although you can create an Overlay directly, it's most common to use the overlay created by the Navigator in a WidgetsApp or a MaterialApp. The navigator uses its overlay to manage the visual appearance of its routes.

The Overlay widget uses a custom stack implementation, which is very similar to the Stack widget. The main use case of Overlay is related to navigation and being able to insert widgets on top of the pages in an app. To simply display a stack of widgets, consider using Stack instead.

This example shows how to use the Overlay to highlight the NavigationBar destination.

To create a local project with this code sample, run:
flutter create --sample=widgets.Overlay.1 mysample

Constructors

Overlay({Key? key, List<OverlayEntry> initialEntries = const <OverlayEntry>[], Clip clipBehavior = Clip.hardEdge}): Creates an overlay.
const

Properties

clipBehavior → Clip: The content will be clipped (or not) according to this option.
final
hashCode → int: The hash code for this object.
nonVirtual">@nonVirtualread-onlyinherited
initialEntries → List<OverlayEntry>: The entries to include in the overlay initially.
final
key → Key?: Controls how one widget replaces another widget in the tree.
finalinherited
runtimeType → Type: A representation of the runtime type of the object.
read-onlyinherited

Methods

createElement() → StatefulElement: Creates a StatefulElement to manage this widget's location in the tree.
inherited
createState() → OverlayState: 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

Static Methods

of(BuildContext context, {bool rootOverlay = false, Widget? debugRequiredFor}) → OverlayState?: The state from the closest instance of this class that encloses the given context.

Flutter
widgets
Overlay class