InkWell class Null safety

A rectangular area of a Material that responds to touch.

For a variant of this widget that does not clip splashes, see InkResponse.

The following diagram shows how an InkWell looks when tapped, when using default values.

The highlight is a rectangle the size of the box.

The InkWell 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 InkWell 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 InkWell (as an ancestor to the ink well). The MaterialType.transparency material kind can be used for this purpose.

InkWell isn't clipping properly

If you want to clip an InkWell or any Ink widgets you need to keep in mind that the Material that the Ink will be printed on is responsible for clipping. This means you can't wrap the Ink widget in a clipping widget directly, since this will leave the Material not clipped (and by extension the printed Ink widgets as well).

An easy solution is to deliberately wrap the Ink widgets you want to clip in a Material, and wrap that in a clipping widget instead. See Ink for an example.

The ink splashes don't track the size of an animated container

If the size of an InkWell's Material ancestor changes while the InkWell's splashes are expanding, you may notice that the splashes aren't clipped correctly. This can't be avoided.

An example of this situation is as follows:

link
Tap the container to cause it to grow. Then, tap it again and hold before the widget reaches its maximum size to observe the clipped ink splash.
To create a local project with this code sample, run:
flutter create --sample=material.InkWell.1 mysample

An InkWell's splashes will not properly update to conform to changes if the size of its underlying Material, where the splashes are rendered, changes during animation. You should avoid using InkWells within Material widgets that are changing size.

See also:

Inheritance

Constructors

InkWell({Key? key, Widget? child, GestureTapCallback? onTap, GestureTapCallback? onDoubleTap, GestureLongPressCallback? onLongPress, GestureTapDownCallback? onTapDown, GestureTapUpCallback? onTapUp, GestureTapCallback? onTapCancel, ValueChanged<bool>? onHighlightChanged, ValueChanged<bool>? onHover, MouseCursor? mouseCursor, Color? focusColor, Color? hoverColor, Color? highlightColor, MaterialStateProperty<Color?>? overlayColor, Color? splashColor, InteractiveInkFeatureFactory? splashFactory, double? radius, BorderRadius? borderRadius, ShapeBorder? customBorder, bool? enableFeedback = true, bool excludeFromSemantics = false, FocusNode? focusNode, bool canRequestFocus = true, ValueChanged<bool>? onFocusChange, bool autofocus = false, MaterialStatesController? statesController})
Creates an ink well.
const

Properties

autofocus → bool
True if this widget will be selected as the initial focus when no other node in its scope is currently focused.
finalinherited
borderRadius → BorderRadius?
The clipping radius of the containing rect. This is effective only if customBorder is null.
finalinherited
canRequestFocus → bool
If true, this widget may request the primary focus.
finalinherited
child → Widget?
The widget below this widget in the tree.
finalinherited
containedInkWell → bool
Whether this ink response should be clipped its bounds.
finalinherited
customBorder → ShapeBorder?
The custom clip border which overrides borderRadius.
finalinherited
enableFeedback → bool
Whether detected gestures should provide acoustic and/or haptic feedback.
finalinherited
excludeFromSemantics → bool
Whether to exclude the gestures introduced by this widget from the semantics tree.
finalinherited
focusColor → Color?
The color of the ink response when the parent widget is focused. If this property is null then the focus color of the theme, ThemeData.focusColor, will be used.
finalinherited
focusNode → FocusNode?
An optional focus node to use as the focus node for this widget.
finalinherited
hashCode → int
The hash code for this object.
nonVirtual">@nonVirtualread-onlyinherited
highlightColor → Color?
The highlight color of the ink response when pressed. If this property is null then the highlight color of the theme, ThemeData.highlightColor, will be used.
finalinherited
highlightShape → BoxShape
The shape (e.g., circle, rectangle) to use for the highlight drawn around this part of the material when pressed, hovered over, or focused.
finalinherited
hoverColor → Color?
The color of the ink response when a pointer is hovering over it. If this property is null then the hover color of the theme, ThemeData.hoverColor, will be used.
finalinherited
key → Key?
Controls how one widget replaces another widget in the tree.
finalinherited
mouseCursor → MouseCursor?
The cursor for a mouse pointer when it enters or is hovering over the widget.
finalinherited
onDoubleTap → GestureTapCallback?
Called when the user double taps this part of the material.
finalinherited
onFocusChange → ValueChanged<bool>?
Handler called when the focus changes.
finalinherited
onHighlightChanged → ValueChanged<bool>?
Called when this part of the material either becomes highlighted or stops being highlighted.
finalinherited
onHover → ValueChanged<bool>?
Called when a pointer enters or exits the ink response area.
finalinherited
onLongPress → GestureLongPressCallback?
Called when the user long-presses on this part of the material.
finalinherited
onTap → GestureTapCallback?
Called when the user taps this part of the material.
finalinherited
onTapCancel → GestureTapCallback?
Called when the user cancels a tap that was started on this part of the material.
finalinherited
onTapDown → GestureTapDownCallback?
Called when the user taps down this part of the material.
finalinherited
onTapUp → GestureTapUpCallback?
Called when the user releases a tap that was started on this part of the material. onTap is called immediately after.
finalinherited
overlayColor → MaterialStateProperty<Color?>?
Defines the ink response focus, hover, and splash colors.
finalinherited
radius → double?
The radius of the ink splash.
finalinherited
runtimeType → Type
A representation of the runtime type of the object.
read-onlyinherited
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.
finalinherited
splashFactory → InteractiveInkFeatureFactory?
Defines the appearance of the splash.
finalinherited
statesController → MaterialStatesController?
Represents the interactive "state" of this widget in terms of a set of MaterialStates, like MaterialState.pressed and MaterialState.focused.
finalinherited

Methods

build(BuildContext context) → Widget
Describes the part of the user interface represented by this widget.
inherited
createElement() → StatelessElement
Creates a StatelessElement to manage this widget's location in the tree.
inherited
debugCheckContext(BuildContext context) → bool
Asserts that the given context satisfies the prerequisites for this class.
mustCallSuper">@mustCallSuperinherited
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
getRectCallback(RenderBox referenceBox) → RectCallback?
The rectangle to use for the highlight effect and for clipping the splash effects if containedInkWell is true.
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