widgets library - Dart API

The Flutter widgets framework.

To use, import package:flutter/widgets.dart.

Constants

kAlwaysCompleteAnimation → Animation<double>: An animation that is always complete.

const _AlwaysCompleteAnimation<double>()
kAlwaysDismissedAnimation → Animation<double>: An animation that is always dismissed.

const _AlwaysDismissedAnimation<double>()

Typedefs

AnimationStatusListener(AnimationStatus status) → void: Signature for listeners attached using Animation.addStatusListener.
CreateRectTween(Rect begin, Rect end) → RectTween: Signature for a function that takes two Rect instances and returns a RectTween that transitions between them.
DismissDirectionCallback(DismissDirection direction) → void: Signature used by Dismissable to indicate that it has been dismissed in the given direction.
DraggableCanceledCallback(Velocity velocity, Offset offset) → void: Signature for when a Draggable is dropped without being accepted by a DragTarget.
DragTargetAccept(T data) → void: Signature for causing a DragTarget to accept the given data.
DragTargetBuilder(BuildContext context, List<T> candidateData, List rejectedData) → Widget: Signature for building children of a DragTarget.
DragTargetWillAccept(T data) → bool: Signature for determining whether the given data will be accepted by a DragTarget.
ElementVisitor(Element element) → void: Signature for the callback to BuildContext.visitChildElements.
ExtentsChangedCallback(double contentExtent, double containerExtent) → void: Signature for reporting the interior and exterior dimensions of a viewport.
FormFieldBuilder(FormFieldState<T> field) → Widget: Signature for building the widget representing the form field.
FormFieldSetter(T newValue) → void: Signature for being notified when a form field changes value.
FormFieldValidator(T value) → String: Signature for validating a form field.
GestureDragCancelCallback() → void: Signature for when the pointer that previously triggered a GestureDragDownCallback did not complete.
GestureDragDownCallback(DragDownDetails details) → void: Signature for when a pointer has contacted the screen and might begin to move.
GestureDragEndCallback(DragEndDetails details) → void: Signature for when a pointer that was previously in contact with the screen and moving is no longer in contact with the screen.
GestureDragStartCallback(DragStartDetails details) → void: Signature for when a pointer has contacted the screen and has begun to move.
GestureDragUpdateCallback(DragUpdateDetails details) → void: Signature for when a pointer that is in contact with the screen and moving has moved again.
GestureLongPressCallback() → void: Signature for when a pointer has remained in contact with the screen at the same location for a long period of time.
GestureRecognizerFactory(GestureRecognizer recognizer) → GestureRecognizer: Signature for creating gesture recognizers.
GestureScaleEndCallback(ScaleEndDetails details) → void: Signature for when the pointers are no longer in contact with the screen.
GestureScaleStartCallback(ScaleStartDetails details) → void: Signature for when the pointers in contact with the screen have established a focal point and initial scale of 1.0.
GestureScaleUpdateCallback(ScaleUpdateDetails details) → void: Signature for when the pointers in contact with the screen have indicated a new focal point and/or scale.
GestureTapCallback() → void: Signature for when a tap has occurred.
GestureTapCancelCallback() → void: Signature for when the pointer that previously triggered a GestureTapDownCallback will not end up causing a tap.
GestureTapDownCallback(TapDownDetails details) → void: Signature for when a pointer that might cause a tap has contacted the screen.
GestureTapUpCallback(TapUpDetails details) → void: Signature for when a pointer that will trigger a tap has stopped contacting the screen.
GlobalKeyRemoveListener(GlobalKey key) → void: Signature for a callback when a global key is removed from the tree.
IndexedWidgetBuilder(BuildContext context, int index) → Widget: Signature for a function that creates a widget for a given index, e.g., in a list.
ItemListBuilder(BuildContext context, int start, int count) → List<Widget>: Signature of a callback that returns the sublist of widgets in the given range.
LayoutWidgetBuilder(BuildContext context, BoxConstraints constraints) → Widget: The signature of the LayoutBuilder builder function.
LazyBlockExtentsChangedCallback(int firstIndex, int lastIndex, double firstStartOffset, double lastEndOffset, double minScrollOffset, double containerExtent) → void: Signature used by LazyBlockViewport to report its interior and exterior dimensions.
LocaleChangedCallback(Locale locale) → Future<LocaleQueryData>: Signature for a function that is called when the operating system changes the current locale.
NotificationListenerCallback(T notification) → bool: Signature for Notification listeners.
OrientationWidgetBuilder(BuildContext context, Orientation orientation) → Widget: Signature for a function that builds a widget given an Orientation.
PointerCancelEventListener(PointerCancelEvent event) → void: Signature for listening to PointerCancelEvent events.
PointerDownEventListener(PointerDownEvent event) → void: Signature for listening to PointerDownEvent events.
PointerMoveEventListener(PointerMoveEvent event) → void: Signature for listening to PointerMoveEvent events.
PointerUpEventListener(PointerUpEvent event) → void: Signature for listening to PointerUpEvent events.
RouteFactory(RouteSettings settings) → Route: Creates a route for the given route settings.
RoutePredicate(Route route) → bool: Signature for the Navigator.popUntil predicate argument.
ScrollBuilder(BuildContext context, ScrollableState state) → Widget: Signature for building a widget based on ScrollableState.
ScrollListener(double scrollOffset) → void: Signature for callbacks that receive a scroll offset.
ShaderCallback(Rect bounds) → Shader: Signature for a function that creates a Shader for a given Rect.
SnapOffsetCallback(double scrollOffset, Size containerSize) → double: Signature for determining the offset at which scrolling should snap.
StatefulWidgetBuilder(BuildContext context, StateSetter setState) → Widget: Signature for the builder callback used by StatefulBuilder.
StateSetter(VoidCallback fn) → void: The signature of State.setState functions.
TextSelectionOverlayChanged(InputValue value, Rect caretRect) → void: Signature for reporting changes to the selection component of an InputValue for the purposes of a TextSelectionOverlay. The caretRect argument gives the location of the caret in the coordinate space of the RenderBox given by the TextSelectionOverlay.renderObject.
TotalExtentEstimator(int firstIndex, int lastIndex, double minOffset, double firstStartOffset, double lastEndOffset) → double: Signature for callbacks that estimate the total height of a LazyBlock's contents.
TransitionBuilder(BuildContext context, Widget child) → Widget: A builder that builds a widget given a child.
TweenConstructor(T targetValue) → Tween<T>: Signature for a Tween factory.
TweenVisitor(Tween<T> tween, T targetValue, TweenConstructor<T> constructor) → Tween<T>: Signature for callbacks passed to AnimatedWidgetBaseState.forEachTween.
ValueChanged(T value) → void: Signature for callbacks that report that an underlying value has changed.
ValueGetter() → T: Signature for callbacks that are to report a value on demand.
ValueSetter(T value) → void: Signature for callbacks that report that a value has been set.
ViewportDimensionsChangeCallback(ViewportDimensions dimensions) → Offset: Signature for notifications about RenderViewport dimensions changing.
VoidCallback() → void: Signature of callbacks that have no arguments and return no data.
WidgetBuilder(BuildContext context) → Widget: Signature for a function that creates a widget, e.g. StatelessWidget.build or State.build.

Properties

debugPrint → DebugPrintCallback: Prints a message to the console, which you can access using the "flutter" tool's "logs" command ("flutter logs").

read / write
debugPrintBuildScope → bool: Log all calls to BuildOwner.buildScope.

read / write
debugPrintGlobalKeyedWidgetLifecycle → bool: Log when widgets with global keys are deactivated and log when they are reactivated (retaken).

read / write
debugPrintRebuildDirtyWidgets → bool: Log the dirty widgets that are built each frame.

read / write
debugPrintScheduleBuildForStacks → bool: Log the call stacks that mark widgets as needing to be rebuilt.

read / write
debugProfileBuildsEnabled → bool: Adds Timeline events for every Widget built.

read / write
kDefaultSpringForce → SpringForce: A spring force with reasonable default values.

read-only
kPixelScrollTolerance → Tolerance: The accuracy to which scrolling is computed.

read-only

Functions

applyImageFit(ImageFit fit, Size inputSize, Size outputSize) → FittedSizes: Apply an ImageFit value.
createLocalImageConfiguration(BuildContext context, { Size size }) → ImageConfiguration: Creates an ImageConfiguration based on the given BuildContext (and optionally size).
debugAssertAllWidgetVarsUnset(String reason) → bool: Returns true if none of the widget library debug variables have been changed.
debugCheckHasTable(BuildContext context) → bool: Asserts that the given context has a Table ancestor.
debugChildrenHaveDuplicateKeys(Widget parent, Iterable<Widget> children) → bool: Asserts if the given child list contains any duplicate non-null keys.
debugDumpApp() → void: Print a string representation of the currently running app.
debugItemsHaveDuplicateKeys(Iterable<Widget> items) → bool: Asserts if the given list of items contains any duplicate non-null keys.
debugWidgetBuilderValue(Widget widget, Widget built) → void: Asserts that the built widget is not null.
hashList(Iterable<Object> args) → int: Combine the hashCodes of an arbitrary number of values from an Iterable into one value. This function will return the same value if given "null" as if given an empty list.
hashValues(Object arg01, Object arg02, [ Object arg03 = _hashEnd, Object arg04 = _hashEnd, Object arg05 = _hashEnd, Object arg06 = _hashEnd, Object arg07 = _hashEnd, Object arg08 = _hashEnd, Object arg09 = _hashEnd, Object arg10 = _hashEnd, Object arg11 = _hashEnd, Object arg12 = _hashEnd, Object arg13 = _hashEnd, Object arg14 = _hashEnd, Object arg15 = _hashEnd, Object arg16 = _hashEnd, Object arg17 = _hashEnd, Object arg18 = _hashEnd, Object arg19 = _hashEnd, Object arg20 = _hashEnd ]) → int: Combine up to twenty values' hashCodes into one value.
paintImage({Canvas canvas, Rect rect, Image image, ColorFilter colorFilter, ImageFit fit, ImageRepeat repeat: ImageRepeat.noRepeat, Rect centerSlice, FractionalOffset alignment }) → void: Paints an image into the given rectangle in the canvas.
runApp(Widget app) → void: Inflate the given widget and attach it to the screen.

Enums

AnimationStatus: The status of an animation
AppLifecycleState: States that an application can be in.
Axis: The two cardinal directions in two dimensions.
BannerLocation: Where to show a Banner.
BlurStyle: Styles to use for blurs in MaskFilter objects.
BorderStyle: The style of line to draw for a BorderSide in a Border.
BoxShape: The shape to use when rendering a BoxDecoration.
CrossAxisAlignment: How the children should be placed along the cross axis in a flex layout.
CrossFadeState: Specifies which of two children to show. See AnimatedCrossFade.
DismissDirection: The direction in which a Dismissable can be dismissed.
DragAnchor: Where the Draggable should be anchored during a drag.
FilterQuality: Quality levels for image filters.
FlexFit: How the child is inscribed into the available space.
FlutterLogoStyle: Possible ways to draw Flutter's logo.
FontStyle: Whether to slant the glyphs in the font
HitTestBehavior: How to behave during hit tests.
ImageFit: How an image should be inscribed into a box.
ImageRepeat: How to paint any portions of a box not covered by an image.
MainAxisAlignment: How the children should be placed along the main axis in a flex layout.
MainAxisSize: How much space space should be occupied in the main axis.
Orientation: Whether in portrait or landscape.
Overflow: Whether overflowing children should be clipped, or their overflow be visible.
PageableListFlingBehavior: Controls how a pageable list should behave during a fling.
PaintingStyle: Strategies for painting shapes and paths on a canvas.
ScrollableEdge: Identifies one or both limits of a Scrollable in terms of its scrollDirection.
ScrollNotificationKind: Indicates if a ScrollNotification indicates the start, end or the middle of a scroll.
StrokeCap: Styles to use for line endings.
TableCellVerticalAlignment: Vertical alignment options for cells in RenderTable objects.
TargetPlatform: The platform that user interaction should adapt to target.
TextAffinity: Whether a TextPosition is visually upstream or downstream of its offset.
TextAlign: Whether to align text horizontally
TextBaseline: A horizontal line used for aligning text
TextDecorationStyle: The style in which to draw a text decoration
TextDirection: A direction in which text flows.
TextInputType: For which type of information to optimize the text input control.
TextOverflow: How overflowing text should be handled.
TextSelectionHandleType: Which type of selection handle to be displayed.
TileMode: Defines what happens at the edge of the gradient.
TransferMode: Algorithms to use when painting on the canvas.
VertexMode: Defines how a list of points is interpreted when drawing a set of triangles.
ViewportAnchor: The end of the viewport from which the paint offset is computed.

Classes

AbsorbPointer: A widget that absorbs pointers during hit testing.
Align: A widget that aligns its child within itself and optionally sizes itself based on the child's size.
AlwaysStoppedAnimation: An animation that is always stopped at a given value.
Animatable: An object that can produce a value of type T given an Animation as input.
AnimatedBuilder: A general-purpose widget for building animations.
AnimatedContainer: A container that gradually changes its values over a period of time.
AnimatedCrossFade: A widget that cross-fades between two given children and animates itself between their sizes.
AnimatedDefaultTextStyle: Animated version of DefaultTextStyle which automatically transitions the default text style (the text style to apply to descendant Text widgets without explicit style) over a given duration whenever the given style changes.
AnimatedModalBarrier: A widget that prevents the user from interacting with widgets behind itself.
AnimatedOpacity: Animated version of Opacity which automatically transitions the child's opacity over a given duration whenever the given opacity changes.
AnimatedPositioned: Animated version of Positioned which automatically transitions the child's position over a given duration whenever the given position changes.
AnimatedSize: Animated widget that automatically transitions its size over a given duration whenever the given child's size changes.
AnimatedWidget: A widget that rebuilds when the given animation changes value.
AnimatedWidgetBaseState: A base class for widgets with implicit animations.
Animation: An animation with a value of type T
AnimationController: A controller for an animation.
AnimationEagerListenerMixin: A mixin that replaces the didRegisterListener/didUnregisterListener contract with a dispose contract.
AnimationLazyListenerMixin: A mixin that helps listen to another object only when this object has registered listeners.
AnimationLocalListenersMixin: A mixin that implements the addListener/removeListener protocol and notifies all the registered listeners when notifyListeners is called.
AnimationLocalStatusListenersMixin: A mixin that implements the addStatusListener/removeStatusListener protocol and notifies all the registered listeners when notifyStatusListeners is called.
AnimationMean: An animation of doubles that tracks the mean of two other animations.
AnimationWithParentMixin: Implements most of the Animation interface, by deferring its behavior to a given parent Animation. To implement an Animation that proxies to a parent, this class plus implementing "T get value" is all that is necessary.
AspectRatio: A widget that attempts to size the child to a specific aspect ratio.
AssetImage: Fetches an image from an AssetBundle, having determined the exact image to use based on the context.
AutoLayout: A widget that uses the cassowary constraint solver to automatically size and position children.
AutoLayoutChild: A widget that provides constraints for a child of an AutoLayout widget.
AutoLayoutDelegate: Subclass to control the layout of a RenderAutoLayout.
AutoLayoutRect: Hosts the edge parameters and vends useful methods to construct expressions for constraints. Also sets up and manages implicit constraints and edit variables.
BackdropFilter: A widget that applies a filter to the existing painted content and then paints child.
BackgroundImage: A background image for a box.
Banner: Displays a diagonal message above the corner of another widget.
BannerPainter: Paints a Banner.
Baseline: A widget that positions its child according to the child's baseline.
Block: A scrolling list of variably-sized children.
BlockBody: A widget that uses the block layout algorithm for its children.
Border: A border of a box, comprised of four sides.
BorderRadius: An immutable set of radii for each corner of a rectangle.
BorderSide: A side of a border of a box.
BoundedBehavior: A scroll behavior that prevents the user from exceeding scroll bounds.
BoxConstraints: Immutable layout constraints for box layout.
BoxConstraintsTween: An interpolation between two BoxConstraints.
BoxDecoration: An immutable description of how to paint a box.
BoxPainter: A stateful class that can paint a particular Decoration.
BoxShadow: A shadow cast by a box.
BuildableElement: An Element that can be marked dirty and rebuilt.
BuildContext: A handle to the location of a widget in the widget tree.
Builder: A platonic widget that calls a closure to obtain its child widget.
BuildOwner: Manager class for the widgets framework.
Canvas: An interface for recording graphical operations.
Center: A widget that centers its child within itself.
CheckedModeBanner: Displays a Banner saying "SLOW MODE" when running in checked mode. MaterialApp builds one of these by default. Does nothing in release mode.
ClampOverscrolls: A widget that controls whether viewport descendants will overscroll their contents. Overscrolling is clamped at the beginning or end or both according to the edge parameter.
ClipOval: A widget that clips its child using an oval.
ClipPath: A widget that clips its child using a path.
ClipRect: A widget that clips its child using a rectangle.
ClipRRect: A widget that clips its child using a rounded rectangle.
Color: An immutable 32 bit color value in ARGB
ColorFilter: A description of a color filter to apply when drawing a shape or compositing a layer with a particular Paint. A color filter is a function that takes two colors, and outputs one color. When applied during compositing, it is independently applied to each pixel of the layer being drawn before the entire layer is merged with the destination.
ColorTween: An interpolation between two colors.
Column: A widget that displays its children in a vertical array.
ComponentElement: An Element that composes other Elements.
CompoundAnimation: An interface for combining multiple Animations. Subclasses need only implement the value getter to control how the child animations are combined. Can be chained to combine more than 2 animations.
ConstrainedBox: A widget that imposes additional constraints on its child.
Container: A convenience widget that combines common painting, positioning, and sizing widgets.
Cubic: A cubic polynomial mapping of the unit interval.
Curve: A mapping of the unit interval to the unit interval.
CurvedAnimation: An animation that applies a curve to another animation.
Curves: A collection of common animation curves.
CurveTween: Transforms the value of the given animation by the given curve.
CustomClipper: An interface for providing custom clips.
CustomGrid: A widget that creates a grid using a custom delegate.
CustomMultiChildLayout: A widget that uses a delegate to size and position multiple children.
CustomPaint: A widget that provides a canvas on which to draw during the paint phase.
CustomPainter: The interface used by CustomPaint (in the widgets library) and RenderCustomPaint (in the rendering library).
CustomSingleChildLayout: A widget that defers the layout of its single child to a delegate.
DecoratedBox: A widget that paints a Decoration either before or after its child paints.
Decoration: A description of a box decoration (a decoration applied to a Rect).
DecorationTween: An interpolation between two Decorations.
DefaultAssetBundle: A widget that determines the default asset bundle for its descendants.
DefaultTextStyle: The text style to apply to descendant Text widgets without explicit style.
Dismissable: A widget that can be dismissed by dragging in the indicated direction.
DragDownDetails: Details for GestureDragDownCallback.
DragEndDetails: Details for GestureDragEndCallback.
Draggable: A widget that can be dragged from to a DragTarget.
DragStartDetails: Details for GestureDragStartCallback.
DragTarget: A widget that receives data when a Draggable widget is dropped.
DragUpdateDetails: Details for GestureDragUpdateCallback.
EdgeInsets: An immutable set of offsets in each of the four cardinal directions.
EdgeInsetsTween: An interpolation between two EdgeInsetss.
ElasticInCurve: An oscillating curve that grows in magnitude while overshooting its bounds.
ElasticInOutCurve: An oscillating curve that grows and then shrinks in magnitude while overshooting its bounds.
ElasticOutCurve: An oscillating curve that shrinks in magnitude while overshooting its bounds.
Element: An instantiation of a Widget at a particular location in the tree.
ErrorWidget: A widget that renders an exception's message.
ExactAssetImage: Fetches an image from an AssetBundle, associating it with the given scale.
ExcludeSemantics: A widget that drops all the semantics of its descendants.
Expanded: A widget that expands a child of a Row, Column, or Flex.
ExtentScrollBehavior: A scroll behavior for a scrollable widget with linear extent (i.e. that only scrolls along one axis).
FadeTransition: Animates the opacity of a widget.
FileImage: Decodes the given File object as an image, associating it with the given scale.
FittedBox: Scales and positions its child within itself according to fit.
FittedSizes: The pair of sizes returned by applyImageFit.
FixedColumnCountGrid: A widget that uses a grid layout with a fixed column count.
FixedColumnCountGridDelegate: A GridDelegate that divides the grid's width evenly for a fixed number of columns.
FixedColumnWidth: Sizes the column to a specific number of pixels.
Flex: A widget that displays its children in a one-dimensional array.
FlexColumnWidth: Sizes the column by taking a part of the remaining space once all the other columns have been laid out.
Flexible: A widget that controls how a child of a Row, Column, or Flex flexes.
FlippedCurve: A curve that is the reversed inversion of its given curve.
Flow: A widget that implements the flow layout algorithm.
FlowDelegate: A delegate that controls the appearance of a flow layout.
FlowPaintingContext: A context in which a FlowDelegate paints.
FlutterLogoDecoration: An immutable description of how to paint Flutter's logo.
Focus: A scope for managing the focus state of descendant widgets.
FontWeight: The thickness of the glyphs used to draw the text
Force: A factory for simulations.
Form: An optional container for grouping together multiple form field widgets (e.g. Input widgets).
FormField: A single form field. This widget maintains the current state of the form field, so that updates and validation errors are visually reflected in the UI.
FormFieldState: The current state of a FormField. Passed to the FormFieldBuilder method for use in constructing the form field's widget.
FormState
FractionallySizedBox: A widget that sizes its child to a fraction of the total available space. For more details about the layout algorithm, see RenderFractionallySizedOverflowBox.
FractionalOffset: An offset that's expressed as a fraction of a Size.
FractionalOffsetTween: An interpolation between two fractional offsets.
FractionalTranslation: A widget that applies a translation expressed as a fraction of the box's size before painting its child.
FractionColumnWidth: Sizes the column to a fraction of the table's constraints' maxWidth.
GestureDetector: A widget that detects gestures.
GlobalKey: A key that is unique across the entire app.
GlobalObjectKey: A global key that takes its identity from the object used as its value.
Gradient: A 2D gradient.
GridChildPlacement: Where to place a child within a grid.
GridDelegate: An abstract interface to control the layout of a RenderGrid.
GridDelegateWithInOrderChildPlacement: A GridDelegate the places its children in order throughout the grid.
GridPaper: A widget that draws a rectilinear grid of 1px wide lines.
GridPlacementData: A widget that controls the placement of a child in a grid.
GridRenderObjectWidget: A MultiChildRenderObjectWidget for use with RenderGrid.
GridSpecification: Specifies the geometry of tiles in a grid.
GridViewport: A virtual viewport onto a grid of widgets.
Hero: A widget that marks its child as being a candidate for hero animations.
HeroController: A Navigator observer that manages Hero transitions.
HSVColor: A color represented using alpha, hue, saturation, and value.
IgnorePointer: A widget that is invisible during hit testing.
Image: A widget that displays an image.
ImageConfiguration: Configuration information passed to the ImageProvider.resolve method to select a specific image.
ImageShader: A shader (as used by Paint.shader) that tiles an image.
ImplicitlyAnimatedWidget: An abstract widget for building widgets that gradually change their values over a period of time.
IndexedStack: A Stack that shows a single child from a list of children.
InheritedElement: An Element that uses a InheritedWidget as its configuration.
InheritedWidget: Base class for widgets that efficiently propagate information down the tree.
InputValue: Configuration information for an input field.
Interval: A curve that is 0.0 until start, then curved from 0.0 to 1.0 at end, then 1.0.
IntrinsicColumnWidth: Sizes the column according to the intrinsic dimensions of all the cells in that column.
IntrinsicHeight: A widget that sizes its child to the child's intrinsic height.
IntrinsicWidth: A widget that sizes its child to the child's intrinsic width.
IntTween: An interpolation between two integers that rounds.
Key: A Key is an identifier for Widgets and Elements.
KeyedSubtree: A widget that builds its child.
LabeledGlobalKey: A global key with a debugging label.
LayoutBuilder: Builds a widget tree that can depend on the parent widget's size.
LayoutChangedNotification: Indicates that the layout of one of the descendants of the object receiving this notification has changed in some way, and that therefore any assumptions about that layout are no longer valid.
LayoutId: Meta data for identifying children in a CustomMultiChildLayout.
LazyBlock: An infinite scrolling list of variably-sized children.
LazyBlockBuilder: Uses an IndexedWidgetBuilder to provide children for LazyBlock.
LazyBlockChildren: Uses a List<Widget> to provide children for LazyBlock.
LazyBlockDelegate: Provides children for LazyBlock or LazyBlockViewport.
LazyBlockViewport: A viewport on an infinite list of variable height children.
LazyListViewport: A virtual viewport onto an extremely large or infinite list of equally sized children.
LazyPageViewport: A virtual viewport that displays a single child at a time.
LeafRenderObjectElement: An Element that uses a LeafRenderObjectWidget as its configuration.
LeafRenderObjectWidget: A superclass for RenderObjectWidgets that configure RenderObject subclasses that have no children.
LimitedBox: A box that limits its size only when it's unconstrained.
LinearGradient: A 2D linear gradient.
Listener: A widget that calls callbacks in response to pointer events.
ListViewport: A virtual viewport onto a list of equally sized children.
Locale: An identifier used to select a user's language and formatting preferences, consisting of a language and a country. This is a subset of locale identifiers as defined by BCP 47.
LocaleQuery: Establishes a subtree in which locale queries resolve to the given data.
LocaleQueryData: Superclass for locale-specific data provided by the application.
LocalHistoryEntry: An entry in the history of a LocalHistoryRoute.
LocalHistoryRoute: A route that can handle back navigations internally by popping a list.
LocalKey: A key that is not a GlobalKey.
LongPressDraggable: Makes its child draggable starting from long press.
MaskFilter: A mask filter to apply to shapes as they are painted. A mask filter is a function that takes a bitmap of color pixels, and returns another bitmap of color pixels.
Matrix4: 4D Matrix. Values are stored in column major order.
Matrix4Tween: An interpolation between two Matrix4s.
MatrixUtils: Utility functions for working with matrices.
MaxColumnWidth: Sizes the column such that it is the size that is the maximum of two column width specifications.
MaxTileWidthGrid: A widget that uses a grid layout with a maximum tile width.
MaxTileWidthGridDelegate: A GridDelegate that fills the width with a variable number of tiles.
MediaQuery: Establishes a subtree in which media queries resolve to the given data.
MediaQueryData: Information about a piece of media (e.g., a window).
MergeSemantics: A widget that merges the semantics of its descendants.
MetaData: Holds opaque meta data in the render tree.
Mimic: A widget that copies the appearance of another widget.
Mimicable: A widget that can be copied by a Mimic.
MimicableHandle: An opaque reference to a widget that can be mimicked.
MimicableState: The state for a Mimicable.
MimicOverlayEntry: An overlay entry that is mimicking another widget.
MinColumnWidth: Sizes the column such that it is the size that is the minimum of two column width specifications.
ModalBarrier: A widget that prevents the user from interacting with widgets behind itself.
ModalRoute: A route that blocks interaction with previous routes.
MultiChildLayoutDelegate: A delegate that controls the layout of multiple children.
MultiChildRenderObjectElement: An Element that uses a MultiChildRenderObjectWidget as its configuration.
MultiChildRenderObjectWidget: A superclass for RenderObjectWidgets that configure RenderObject subclasses that have a single list of children. (This superclass only provides the storage for that child list, it doesn't actually provide the updating logic.)
NavigationGestureController: Interface describing an object returned by the Route.startPopGesture method, allowing the route's transition animations to be controlled by a drag or other user gesture.
Navigator: A widget that manages a set of child widgets with a stack discipline.
NavigatorObserver: An interface for observing the behavior of a Navigator.
NavigatorState: The state for a Navigator widget.
NetworkImage: Fetches the given URL from the network, associating it with the given scale.
Notification: A notification that can bubble up the widget tree.
NotificationListener: A widget that listens for Notifications bubbling up the tree.
ObjectKey: A key that takes its identity from the object used as its value.
Offset: An immutable 2D floating-point offset.
Offstage: A widget that lays the child out as if it was in the tree, but without painting anything, without making the child available for hit testing, and without taking any room in the parent.
Opacity: A widget that makes its child partially transparent.
OrientationBuilder: Builds a widget tree that can depend on the parent widget's orientation.
OverflowBox: A widget that imposes different constraints on its child than it gets from its parent, possibly allowing the child to overflow the parent.
Overlay: A Stack of entries that can be managed independently.
OverlayEntry: A place in an Overlay that can contain a widget.
OverlayRoute: A route that displays widgets in the Navigator's Overlay.
OverlayState: The current state of an Overlay.
OverscrollBehavior: A scroll behavior that lets the user scroll beyond the scroll bounds with some resistance.
OverscrollWhenScrollableBehavior: A scroll behavior that lets the user scroll beyond the scroll bounds only when the bounds are disjoint.
Padding: A widget that insets its child by the given padding.
Pageable: A base class for widgets that display one page at a time.
PageableLazyList: A widget that pages through a lazily constructed list of children.
PageableList: A widget that pages through an iterable list of children.
PageableListState: State for a PageableList widget.
PageableState: State for widgets that subclass Pageable.
PageRoute: A modal route that replaces the entire screen.
PageStorage: A widget that establishes a page storage bucket for this widget subtree.
PageStorageBucket: A storage bucket associated with a page in an app.
PageViewport: A virtual viewport that displays a single child at a time.
Paint: A description of the style to use when drawing on a Canvas.
PaintingContext: A place to paint.
ParentDataElement: An Element that uses a ParentDataWidget as its configuration.
ParentDataWidget: Base class for widgets that hook ParentData information to children of RenderObjectWidgets.
Path: A complex, one-dimensional subset of a plane.
PerformanceOverlay: Displays performance statistics.
Placeholder: A widget whose child can be mutated.
PlaceholderState: State for a Placeholder widget.
Point: An immutable 2D floating-point x,y coordinate pair.
PointerCancelEvent: The input from the pointer is no longer directed towards this receiver.
PointerDownEvent: The pointer has made contact with the device.
PointerEvent: Base class for touch, stylus, or mouse events.
PointerMoveEvent: The pointer has moved with respect to the device while the pointer is in contact with the device.
PointerUpEvent: The pointer has stopped making contact with the device.
PopupRoute: A modal route that overlays a widget over the current route.
Positioned: A widget that controls where a child of a Stack is positioned.
PositionedTransition: Animated version of Positioned which takes a specific Animation<RelativeRect> to transition the child's position from a start position to and end position over the lifetime of the animation.
ProxyAnimation: An animation that is a proxy for another animation.
ProxyElement: An Element that uses a ProxyElement as its configuration.
ProxyWidget: A widget that has exactly one child widget.
RadialGradient: A 2D radial gradient.
Radius: A radius for either circular or elliptical shapes.
RawGestureDetector: A widget that detects gestures described by the given gesture factories.
RawGestureDetectorState: State for a RawGestureDetector.
RawImage: A widget that displays a ui.Image directly.
RawInput: A basic text input control.
RawInputState: State for a RawInput.
RawKeyboardListener: A widget that calls a callback whenever the user presses or releases a key on a keyboard.
Rect: An immutable 2D, axis-aligned, floating-point rectangle whose coordinates are relative to an origin point.
RectTween: An interpolation between two rectangles.
RelativePositionedTransition: Animated version of Positioned which transitions the child's position based on the value of rect relative to a bounding box with the specified size.
RelativeRect: An immutable 2D, axis-aligned, floating-point rectangle whose coordinates are given relative to another rectangle's edges, known as the container. Since the dimensions of the rectangle are relative to those of the container, this class has no width and height members. To determine the width or height of the rectangle, convert it to a Rect using toRect() (passing the container's own Rect), and then examine that object.
RelativeRectTween: An interpolation between two relative rects.
RenderBox: A render object in a 2D cartesian coordinate system.
RenderObject: An object in the render tree.
RenderObjectElement: An Element that uses a RenderObjectWidget as its configuration.
RenderObjectToWidgetAdapter: A bridge from a RenderObject to an Element tree.
RenderObjectToWidgetElement: A RootRenderObjectElement that is hosted by a RenderObject.
RenderObjectWidget: RenderObjectWidgets provide the configuration for RenderObjectElements, which wrap RenderObjects, which provide the actual rendering of the application.
RepaintBoundary: A widget that creates a separate display list for its child.
ReverseAnimation: An animation that is the reverse of another animation.
RichText: A paragraph of rich text.
RootRenderObjectElement: The element at the root of the tree.
RotatedBox: A widget that rotates its child by a integral number of quarter turns.
RotationTransition: Animates the rotation of a widget.
Route: An abstraction for an entry managed by a Navigator.
RouteSettings: Data that might be useful in constructing a Route.
Row: A widget that displays its children in a horizontal array.
RRect: A rounded rectangle with the custom radii for all four corners.
RSTransform: A transform consisting of a translation, a rotation, and a uniform scale.
SawTooth: A sawtooth curve that repeats a given number of times over the unit interval.
ScaleEndDetails: Details for GestureScaleEndCallback.
ScaleStartDetails: Details for GestureScaleStartCallback.
ScaleTransition: Animates the scale of transformed widget.
ScaleUpdateDetails: Details for GestureScaleUpdateCallback.
Scrollable: A base class for scrollable widgets.
ScrollableGrid: A vertically scrollable grid.
ScrollableLazyList: An infinite scrollable list of children that have equal size.
ScrollableList: A scrollable list of children that have equal size.
ScrollableState: Contains the state for common scrolling widgets that scroll only along one axis.
ScrollableViewport: A simple scrolling widget that has a single child.
ScrollBehavior: An interface for controlling the behavior of scrollable widgets.
ScrollConfiguration: A widget that controls descendant Scrollable widgets.
ScrollConfigurationDelegate: Controls how Scrollable widgets in a subtree behave.
ScrollNotification: Indicates that a scrollable descendant is scrolling.
ScrollSimulation: Composite simulation for scrollable interfaces.
Semantics: A widget that annotates the widget tree with a description of the meaning of the widgets.
SemanticsDebugger: A widget that visualizes the semantics for the child.
Shader: Base class for objects such as Gradient and ImageShader which correspond to shaders as used by Paint.shader.
ShaderMask: A widget that applies a mask generated by a Shader to its child.
SingleChildLayoutDelegate: A delegate for computing the layout of a render object with a single child.
SingleChildRenderObjectElement: An Element that uses a SingleChildRenderObjectWidget as its configuration.
SingleChildRenderObjectWidget: A superclass for RenderObjectWidgets that configure RenderObject subclasses that have a single child slot. (This superclass only provides the storage for that child, it doesn't actually provide the updating logic.)
SingleTickerProviderStateMixin: Provides a single Ticker that is configured to only tick while the current tree is enabled, as defined by TickerMode.
Size: Holds a 2D floating-point size.
SizeChangedLayoutNotificaion: Indicates that the size of one of the descendants of the object receiving this notification has changed, and that therefore any assumptions about that layout are no longer valid.
SizeChangedLayoutNotifier: A widget that automatically dispatches a SizeChangedLayoutNotifier when the layout of its child changes.
SizedBox: A box with a specified size.
SizedOverflowBox: A widget that is a specific size but passes its original constraints through to its child, which will probably overflow.
SizeTransition: Animates its own size and clips and aligns the child.
SizeTween: An interpolation between two sizes.
SlideTransition: Animates the position of a widget relative to its normal position.
SpringDescription: Structure that describes a spring's constants.
SpringForce: A factory for spring-based physics simulations.
Stack: A widget that uses the stack layout algorithm for its children.
State: The logic and internal state for a StatefulWidget.
StatefulBuilder: A platonic widget that both has state and calls a closure to obtain its child widget.
StatefulElement: An Element that uses a StatefulWidget as its configuration.
StatefulWidget: A widget that has mutable state.
StatelessElement: An Element that uses a StatelessWidget as its configuration.
StatelessWidget: A widget that does not require mutable state.
StatusTransitionWidget: A widget that rebuilds when the given animation changes status.
StepTween: An interpolation between two integers that floors.
Table: A widget that uses the table layout algorithm for its children.
TableBorder: Border specification for RenderTable.
TableCell: A widget that controls how a child of a Table is aligned.
TableColumnWidth: Base class to describe how wide a column in a RenderTable should be.
TableRow: A horizontal group of cells in a Table.
TapDownDetails: Details for GestureTapDownCallback, such as position.
TapUpDetails: Details for GestureTapUpCallback, such as position.
Text: A run of text with a single style.
TextDecoration: A linear decoration to draw near the text
TextPainter: An object that paints a TextSpan tree into a Canvas.
TextPosition: A visual position in a string of text.
TextRange: A range of characters in a string of text.
TextSelection: A range of text that represents a selection.
TextSelectionControls
TextSelectionDelegate: An interface for manipulating the selection, to be used by the implementor of the toolbar widget.
TextSelectionOverlay: An object that manages a pair of text selection handles.
TextSpan: An immutable span of text.
TextStyle: An immutable style in which paint text.
TextStyleTween: An interpolation between two TextStyles.
Threshold: A curve that is 0.0 until it hits the threshold, then it jumps to 1.0.
TickerMode: Enables or disables tickers (and thus animation controllers) in the widget subtree.
TickerProvider: An interface implemented by classes that can vend Ticker objects.
TickerProviderStateMixin: Provides Ticker objects that are configured to only tick while the current tree is enabled, as defined by TickerMode.
Title: A widget that describes this app in the operating system.
TrainHoppingAnimation: This animation starts by proxying one animation, but can be given a second animation. When their times cross (either because the second is going in the opposite direction, or because the one overtakes the other), the animation hops over to proxying the second animation, and the second animation becomes the new "first" performance.
Transform: A widget that applies a transformation before painting its child.
TransitionRoute: A route with entrance and exit transitions.
Tween: A linear interpolation between a beginning and ending value.
TypeMatcher: This class is a work-around for the "is" operator not accepting a variable value as its right operand
UnboundedBehavior: A scroll behavior that does not prevent the user from exceeding scroll bounds.
UniqueKey: A key that is only equal to itself.
UniqueWidget: Base class for stateful widgets that have exactly one inflated instance in the tree.
ValueKey: A key that uses a value of a particular type to identify itself.
Velocity: A velocity in two dimensions.
Viewport: A widget that's bigger on the inside.
ViewportDimensions: The interior and exterior dimensions of a viewport.
VirtualViewport: An abstract widget whose children are not all materialized.
VirtualViewportElement: An element that materializes a contiguous subset of its children.
VirtualViewportFromBuilder: A VirtualViewport that represents its children using ItemListBuilder.
VirtualViewportFromIterable: A VirtualViewport that represents its children using Iterable<Widget>.
Widget: Describes the configuration for an Element.
WidgetsApp: A convenience class that wraps a number of widgets that are commonly required for an application.
WidgetsBinding: The glue between the widgets layer and the Flutter engine.
WidgetsBindingObserver: Interface for classes that register with the Widgets layer binding.
WidgetsFlutterBinding: A concrete binding for applications based on the Widgets framework. This is the glue that binds the framework to the Flutter engine.
WidgetToRenderBoxAdapter: An adapter for placing a specific RenderBox in the widget tree.

Exceptions / Errors

FlutterError: Error class used to report Flutter-specific assertion failures and contract violations.