Draggable<
A widget that can be dragged from to a DragTarget.
When a draggable widget recognizes the start of a drag gesture, it displays a feedback widget that tracks the user's finger across the screen. If the user lifts their finger while on top of a DragTarget, that target is given the opportunity to accept the data carried by the draggable.
On multitouch devices, multiple drags can occur simultaneously because there can be multiple pointers in contact with the device at once. To limit the number of simultaneous drags, use the maxSimultaneousDrags property. The default is to allow an unlimited number of simultaneous drags.
This widget displays child when zero drags are under way. If childWhenDragging is non-null, this widget instead displays childWhenDragging when one or more drags are underway. Otherwise, this widget always displays child.
See also:
- Inheritance
- Implementers
Constructors
- Draggable({Key key, @required Widget child, @required Widget feedback, T data, Axis axis, Widget childWhenDragging, Offset feedbackOffset: Offset.zero, DragAnchor dragAnchor: DragAnchor.child, Axis affinity, int maxSimultaneousDrags, VoidCallback onDragStarted, DraggableCanceledCallback onDraggableCanceled, DragEndCallback onDragEnd, VoidCallback onDragCompleted, bool ignoringFeedbackSemantics: true })
-
Creates a widget that can be dragged to a DragTarget. [...]
const
Properties
- affinity → Axis
-
Controls how this widget competes with other gestures to initiate a drag. [...]
final
- axis → Axis
-
The Axis to restrict this draggable's movement, if specified. [...]
final
- child → Widget
-
The widget below this widget in the tree. [...]
final
- childWhenDragging → Widget
-
The widget to display instead of child when one or more drags are under way. [...]
final
- data → T
-
The data that will be dropped by this draggable.
final
- dragAnchor → DragAnchor
-
Where this widget should be anchored during a drag.
final
- feedback → Widget
-
The widget to show under the pointer when a drag is under way. [...]
final
- feedbackOffset → Offset
-
The feedbackOffset can be used to set the hit test target point for the
purposes of finding a drag target. It is especially useful if the feedback
is transformed compared to the child.
final
- ignoringFeedbackSemantics → bool
-
Whether the semantics of the feedback widget is ignored when building
the semantics tree. [...]
final
- maxSimultaneousDrags → int
-
How many simultaneous drags to support. [...]
final
- onDragCompleted → VoidCallback
-
Called when the draggable is dropped and accepted by a DragTarget. [...]
final
- onDragEnd → DragEndCallback
-
Called when the draggable is dropped. [...]
final
- onDraggableCanceled → DraggableCanceledCallback
-
Called when the draggable is dropped without being accepted by a DragTarget. [...]
final
- onDragStarted → VoidCallback
-
Called when the draggable starts being dragged.
final
- hashCode → int
-
The hash code for this object. [...]
read-only, inherited
- key → Key
-
Controls how one widget replaces another widget in the tree. [...]
final, inherited
- runtimeType → Type
-
A representation of the runtime type of the object.
read-only, inherited
Methods
-
createRecognizer(
GestureMultiDragStartCallback onStart) → MultiDragGestureRecognizer< MultiDragPointerState> -
Creates a gesture recognizer that recognizes the start of the drag. [...]
@protected
-
createState(
) → _DraggableState< T> -
Creates the mutable state for this widget at a given location in the tree. [...]
override
-
createElement(
) → StatefulElement -
Creates a StatefulElement to manage this widget's location in the tree. [...]
inherited
-
debugDescribeChildren(
) → List< DiagnosticsNode> -
Returns a list of DiagnosticsNode objects describing this node's
children. [...]
@protected, inherited
-
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 toStringDeep. [...]
inherited
-
toString(
{DiagnosticLevel minLevel: DiagnosticLevel.debug }) → String -
Returns 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 ==(
dynamic other) → bool -
The equality operator. [...]
inherited