DraggableScrollableSheet class
A container for a Scrollable that responds to drag gestures by resizing the scrollable until a limit is reached, and then scrolling.
This widget can be dragged along the vertical axis between its
minChildSize, which defaults to 0.25 and maxChildSize, which defaults
to 1.0. These sizes are percentages of the height of the parent container.
The widget coordinates resizing and scrolling of the widget returned by builder as the user drags along the horizontal axis.
The widget will initially be displayed at its initialChildSize which
defaults to 0.5, meaning half the height of its parent. Dragging will work
between the range of minChildSize and maxChildSize (as percentages of the
parent container's height) as long as the builder creates a widget which
uses the provided ScrollController. If the widget created by the
ScrollableWidgetBuilder does not use the provided ScrollController, the
sheet will remain at the initialChildSize.
By default, the widget will stay at whatever size the user drags it to. To
make the widget snap to specific sizes whenever they lift their finger
during a drag, set snap to true. The sheet will snap between
minChildSize and maxChildSize. Use snapSizes to add more sizes for
the sheet to snap between.
The snapping effect is only applied on user drags. Programmatically manipulating the sheet size via DraggableScrollableController.animateTo or DraggableScrollableController.jumpTo will ignore snap and snapSizes.
By default, the widget will expand its non-occupied area to fill available space in the parent. If this is not desired, e.g. because the parent wants to position sheet based on the space it is taking, the expand property may be set to false.
On desktop and web running on desktop platforms, dragging to scroll with a mouse is disabled by default to align with the natural behavior found in other desktop applications.
This behavior is dictated by the ScrollBehavior, and can be changed by adding PointerDeviceKind.mouse to ScrollBehavior.dragDevices. For more info on this, please refer to https://docs.flutter.cn/release/breaking-changes/default-scroll-behavior-drag
Alternatively, this example illustrates how to add a drag handle for desktop applications.
To create a local project with this code sample, run:
flutter create --sample=widgets.DraggableScrollableSheet.1 mysample
- Inheritance
-
- Object
- DiagnosticableTree
- Widget
- StatefulWidget
- DraggableScrollableSheet
Constructors
-
DraggableScrollableSheet({Key? key, double initialChildSize = 0.5, double minChildSize = 0.25, double maxChildSize = 1.0, bool expand = true, bool snap = false, List<
double> ? snapSizes, Duration? snapAnimationDuration, DraggableScrollableController? controller, bool shouldCloseOnMinExtent = true, required ScrollableWidgetBuilder builder}) -
Creates a widget that can be dragged and scrolled in a single gesture.
const
Properties
- builder → ScrollableWidgetBuilder
-
The builder that creates a child to display in this widget, which will
use the provided ScrollController to enable dragging and scrolling
of the contents.
final
- controller → DraggableScrollableController?
-
A controller that can be used to programmatically control this sheet.
final
- expand → bool
-
Whether the widget should expand to fill the available space in its parent
or not.
final
- hashCode → int
-
The hash code for this object.
no setterinherited
- initialChildSize → double
-
The initial fractional value of the parent container's height to use when
displaying the widget.
final
- key → Key?
-
Controls how one widget replaces another widget in the tree.
finalinherited
- maxChildSize → double
-
The maximum fractional value of the parent container's height to use when
displaying the widget.
final
- minChildSize → double
-
The minimum fractional value of the parent container's height to use when
displaying the widget.
final
- runtimeType → Type
-
A representation of the runtime type of the object.
no setterinherited
- shouldCloseOnMinExtent → bool
-
Whether the sheet, when dragged (or flung) to its minimum size, should
cause its parent sheet to close.
final
- snap → bool
-
Whether the widget should snap between snapSizes when the user lifts
their finger during a drag.
final
- snapAnimationDuration → Duration?
-
Defines a duration for the snap animations.
final
-
snapSizes
→ List<
double> ? -
A list of target sizes that the widget should snap to.
final
Methods
-
createElement(
) → StatefulElement -
Creates a StatefulElement to manage this widget's location in the tree.
inherited
-
createState(
) → State< DraggableScrollableSheet> -
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}) → 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