DraggablePanel class final

A floating panel window that can be dragged, parked and grown in place.

Collapsed, it is a small window that can be dragged anywhere and springs to the nearest corner when released, chosen by where its momentum was heading. Flung past a side edge it parks off-screen with a grab tab showing. Tapped, it grows in place into the expanded panel, anchored at the corner it already occupies; dragged down while expanded, it shrinks back.

The panel resolves its placement against the window, so it must be given the whole window. Install it above the app's own content, typically through MaterialApp.builder:

MaterialApp(
  builder: (context, child) => DraggablePanel(
    collapsedBuilder: (context, status) => const Icon(Icons.play_arrow),
    expandedBuilder: (context, status) => const MiniPlayer(),
    child: child,
  ),
)

The panel paints above child but within the same subtree, so a route pushed on top of the app covers it.

Inheritance
Annotations

Constructors

DraggablePanel({required PanelChildBuilder collapsedBuilder, required PanelChildBuilder expandedBuilder, Key? key, Widget? child, DraggablePanelController? controller, DraggablePanelThemeData? theme, PanelHandleBuilder? handleBuilder, PanelBehavior behavior = const PanelBehavior(), PanelSemantics semantics = const PanelSemantics(), ValueChanged<PanelStatus>? onStatusChanged, ValueChanged<PanelPlacement>? onPlacementChanged})
const

Properties

behavior → PanelBehavior
Which interactions the panel accepts.
final
child → Widget?
The application content the panel floats above.
final
collapsedBuilder → PanelChildBuilder
Builds the small, collapsed face of the panel.
final
controller → DraggablePanelController?
Drives the panel from outside. One is created internally when omitted.
final
expandedBuilder → PanelChildBuilder
Builds the large, expanded face of the panel.
final
handleBuilder → PanelHandleBuilder?
Builds the grab affordance on the sliver a parked panel leaves showing.
final
hashCode → int
The hash code for this object.
no setterinherited
key → Key?
Controls how one widget replaces another widget in the tree.
finalinherited
onPlacementChanged → ValueChanged<PanelPlacement>?
Called when the panel comes to rest somewhere new.
final
onStatusChanged → ValueChanged<PanelStatus>?
Called when the panel's phase changes — a handful of times per gesture, never per frame.
final
runtimeType → Type
A representation of the runtime type of the object.
no setterinherited
semantics → PanelSemantics
What the panel announces to assistive technology. Localize these.
final
theme → DraggablePanelThemeData?
Call-site tokens, laid over any DraggablePanelThemeData in ThemeData.extensions and the built-in defaults.
final

Methods

createElement() → StatefulElement
Creates a StatefulElement to manage this widget's location in the tree.
inherited
createState() → State<DraggablePanel>
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