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, CupertinoApp 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.

An Overlay widget requires a Directionality widget to be in scope, so that it can resolve direction-sensitive coordinates of any Positioned.directional children.

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

See also:



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


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


createElement() StatefulElement
Creates a StatefulElement to manage this widget's location in the tree.
createState() OverlayState
Creates the mutable state for this widget at a given location in the tree.
debugDescribeChildren() List<DiagnosticsNode>
Returns a list of DiagnosticsNode objects describing this node's children.
debugFillProperties(DiagnosticPropertiesBuilder properties) → void
Add additional properties associated with the node.
noSuchMethod(Invocation invocation) → dynamic
Invoked when a non-existent method or property is accessed.
toDiagnosticsNode({String? name, DiagnosticsTreeStyle? style}) DiagnosticsNode
Returns a debug representation of the object that is used by debugging tools and by DiagnosticsNode.toStringDeep.
toString({DiagnosticLevel minLevel = DiagnosticLevel.info}) String
A string representation of this object.
toStringDeep({String prefixLineOne = '', String? prefixOtherLines, DiagnosticLevel minLevel = DiagnosticLevel.debug}) String
Returns a string representation of this node and its descendants.
toStringShallow({String joiner = ', ', DiagnosticLevel minLevel = DiagnosticLevel.debug}) String
Returns a one-line detailed description of the object.
toStringShort() String
A short, textual description of this widget.


operator ==(Object other) bool
The equality operator.

Static Methods

maybeOf(BuildContext context, {bool rootOverlay = false}) OverlayState?
The OverlayState from the closest instance of Overlay that encloses the given context, if any.
of(BuildContext context, {bool rootOverlay = false, Widget? debugRequiredFor}) OverlayState
The OverlayState from the closest instance of Overlay that encloses the given context, and, in debug mode, will throw if one is not found.