InkResponse class

An area of a Material that responds to touch. Has a configurable shape and can be configured to clip splashes that extend outside its bounds or not.

For a variant of this widget that is specialized for rectangular areas that always clip splashes, see InkWell.

An InkResponse widget does two things when responding to a tap:

It starts to animate a highlight. The shape of the highlight is determined by highlightShape. If it is a BoxShape.circle, the default, then the highlight is a circle of fixed size centered in the InkResponse. If it is BoxShape.rectangle, then the highlight is a box the size of the InkResponse itself, unless getRectCallback is provided, in which case that callback defines the rectangle. The color of the highlight is set by highlightColor.
Simultaneously, it starts to animate a splash. This is a growing circle initially centered on the tap location. If this is a containedInkWell, the splash grows to the radius while remaining centered at the tap location. Otherwise, the splash migrates to the center of the box as it grows.

The following two diagrams show how InkResponse looks when tapped if the highlightShape is BoxShape.circle (the default) and containedInkWell is false (also the default).

The first diagram shows how it looks if the InkResponse is relatively large:

The highlight is a disc centered in the box, smaller than the child widget.

The second diagram shows how it looks if the InkResponse is small:

The highlight is a disc overflowing the box, centered on the child.

The main thing to notice from these diagrams is that the splashes happily exceed the bounds of the widget (because containedInkWell is false).

The following diagram shows the effect when the InkResponse has a highlightShape of BoxShape.rectangle with containedInkWell set to true. These are the values used by InkWell.

The highlight is a rectangle the size of the box.

The InkResponse widget must have a Material widget as an ancestor. The Material widget is where the ink reactions are actually painted. This matches the material design premise wherein the Material is what is actually reacting to touches by spreading ink.

If a Widget uses this class directly, it should include the following line at the top of its build function to call debugCheckHasMaterial:

assert(debugCheckHasMaterial(context));

Troubleshooting

The ink splashes aren't visible!

If there is an opaque graphic, e.g. painted using a Container, Image, or DecoratedBox, between the Material widget and the InkResponse widget, then the splash won't be visible because it will be under the opaque graphic. This is because ink splashes draw on the underlying Material itself, as if the ink was spreading inside the material.

The Ink widget can be used as a replacement for Image, Container, or DecoratedBox to ensure that the image or decoration also paints in the Material itself, below the ink.

If this is not possible for some reason, e.g. because you are using an opaque CustomPaint widget, alternatively consider using a second Material above the opaque widget but below the InkResponse (as an ancestor to the ink response). The MaterialType.transparency material kind can be used for this purpose.

Constructors

InkResponse({Key key, Widget child, GestureTapCallback onTap, GestureTapDownCallback onTapDown, GestureTapCallback onTapCancel, GestureTapCallback onDoubleTap, GestureLongPressCallback onLongPress, ValueChanged<bool> onHighlightChanged, bool containedInkWell: false, BoxShape highlightShape: BoxShape.circle, double radius, BorderRadius borderRadius, ShapeBorder customBorder, Color highlightColor, Color splashColor, InteractiveInkFeatureFactory splashFactory, bool enableFeedback: true, bool excludeFromSemantics: false }): Creates an area of a Material that responds to touch. [...]
const

Properties

borderRadius → BorderRadius: The clipping radius of the containing rect. This is effective only if customBorder is null. [...]
final
child → Widget: The widget below this widget in the tree. [...]
final
containedInkWell → bool: Whether this ink response should be clipped its bounds. [...]
final
customBorder → ShapeBorder: The custom clip border which overrides borderRadius.
final
enableFeedback → bool: Whether detected gestures should provide acoustic and/or haptic feedback. [...]
final
excludeFromSemantics → bool: Whether to exclude the gestures introduced by this widget from the semantics tree. [...]
final
highlightColor → Color: The highlight color of the ink response. If this property is null then the highlight color of the theme, ThemeData.highlightColor, will be used. [...]
final
highlightShape → BoxShape: The shape (e.g., circle, rectangle) to use for the highlight drawn around this part of the material. [...]
final
onDoubleTap → GestureTapCallback: Called when the user double taps this part of the material.
final
onHighlightChanged → ValueChanged<bool>: Called when this part of the material either becomes highlighted or stops being highlighted. [...]
final
onLongPress → GestureLongPressCallback: Called when the user long-presses on this part of the material.
final
onTap → GestureTapCallback: Called when the user taps this part of the material.
final
onTapCancel → GestureTapCallback: Called when the user cancels a tap that was started on this part of the material.
final
onTapDown → GestureTapDownCallback: Called when the user taps down this part of the material.
final
radius → double: The radius of the ink splash. [...]
final
splashColor → Color: The splash color of the ink response. If this property is null then the splash color of the theme, ThemeData.splashColor, will be used. [...]
final
splashFactory → InteractiveInkFeatureFactory: Defines the appearance of the splash. [...]
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

createState() → _InkResponseState<InkResponse>: Creates the mutable state for this widget at a given location in the tree. [...]
override
debugCheckContext(BuildContext context) → bool: Asserts that the given context satisfies the prerequisites for this class. [...]
@mustCallSuper
debugFillProperties(DiagnosticPropertiesBuilder properties) → void: Add additional properties associated with the node. [...]
override
getRectCallback(RenderBox referenceBox) → RectCallback: The rectangle to use for the highlight effect and for clipping the splash effects if containedInkWell is true. [...]
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
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

material library