RawGestureDetector class Null safety

A widget that detects gestures described by the given gesture factories.

For common gestures, use a GestureRecognizer. RawGestureDetector is useful primarily when developing your own gesture recognizers.

Configuring the gesture recognizers requires a carefully constructed map, as described in gestures and as shown in the example below.

link
This example shows how to hook up a TapGestureRecognizer. It assumes that the code is being used inside a State object with a _last field that is then displayed as the child of the gesture detector. 
RawGestureDetector(
  gestures: <Type, GestureRecognizerFactory>{
    TapGestureRecognizer: GestureRecognizerFactoryWithHandlers<TapGestureRecognizer>(
      () => TapGestureRecognizer(),
      (TapGestureRecognizer instance) {
        instance
          ..onTapDown = (TapDownDetails details) { setState(() { _last = 'down'; }); }
          ..onTapUp = (TapUpDetails details) { setState(() { _last = 'up'; }); }
          ..onTap = () { setState(() { _last = 'tap'; }); }
          ..onTapCancel = () { setState(() { _last = 'cancel'; }); };
      },
    ),
  },
  child: Container(width: 300.0, height: 300.0, color: Colors.yellow, child: Text(_last)),
)

See also:

  • GestureDetector, a less flexible but much simpler widget that does the same thing.
  • Listener, a widget that reports raw pointer events.
  • GestureRecognizer, the class that you extend to create a custom gesture recognizer.
Inheritance

Constructors

RawGestureDetector({Key? key, Widget? child, Map<Type, GestureRecognizerFactory<GestureRecognizer>> gestures = const <Type, GestureRecognizerFactory>{}, HitTestBehavior? behavior, bool excludeFromSemantics = false, SemanticsGestureDelegate? semantics})
Creates a widget that detects gestures.
const

Properties

behavior → HitTestBehavior?
How this gesture detector should behave during hit testing.
final
child → Widget?
The widget below this widget in the tree.
final
excludeFromSemantics → bool
Whether to exclude these gestures from the semantics tree. For example, the long-press gesture for showing a tooltip is excluded because the tooltip itself is included in the semantics tree directly and so having a gesture to show it would result in duplication of information.
final
gestures → Map<Type, GestureRecognizerFactory<GestureRecognizer>>
The gestures that this widget will attempt to recognize.
final
hashCode → int
The hash code for this object.
nonVirtual">@nonVirtualread-onlyinherited
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
semantics → SemanticsGestureDelegate?
Describes the semantics notations that should be added to the underlying render object RenderSemanticsGestureHandler.
final

Methods

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