Box class final

A solid block, bar, or divider — animatable like anything else:

Box(color: Colors.white, size: Size(0.5, 0.01))     // a thin rule
    .animate([Animation.from(const Keyframe(scaleX: 0))]);   // grows in

size components are always fractions of the parent: Size(0.5, 0.01) is half the parent's width by 1% of its height, and null expands to the whole parent. There is no "values above one are pixels" heuristic — for absolute dimensions wrap a plain SizedBox, exactly like the rest of the layout story uses Flutter's real widgets.

An optional shared anchor wraps the box in a SharedElement so it morphs across the boundary it shares with the same anchor in the adjacent scene; null mounts no SharedElement.

Inheritance

• Object
• DiagnosticableTree
• Widget
• StatelessWidget
• Box

Available extensions

• Animate

Constructors

Box({Color? color, Size? size, BoxDecoration? decoration, Anchor? shared, Key? key})

Creates a block filling size of its parent with color or decoration (at most one; neither paints a transparent spacer).

const

Properties

color → Color?

The fill color, or null when decoration (or nothing) paints.

final

decoration → BoxDecoration?

The fill decoration, or null when color (or nothing) paints.

final

hashCode → int

The hash code for this object.

no setter, 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.

no setter, inherited

shared → Anchor?

An optional hero anchor: when non-null the box morphs across the boundary it shares with the same anchor in the adjacent scene. null mounts no SharedElement.

final

size → Size?

The parent-fraction size (width fraction × height fraction), or null to expand to the whole parent.

final

Methods

animate(List<Animation> animations, {Anchor? anchor, TimeRange? window, Defaults? defaults}) → Widget

Available on Widget, provided by the Animate extension

Binds animations to this widget by wrapping it in a MotionTarget.

build(BuildContext context) → Widget

Describes the part of the user interface represented by this widget.

override

createElement() → StatelessElement

Creates a StatelessElement to manage this widget's location in the tree.

inherited

debugDescribeChildren() → List<DiagnosticsNode>

Returns a list of DiagnosticsNode objects describing this node's children.

inherited

debugFillProperties(DiagnosticPropertiesBuilder properties) → void

Add additional properties associated with the node.

inherited

noSuchMethod(Invocation invocation) → dynamic

Invoked when a nonexistent method or property is accessed.

inherited

show({Time? from, Time? to}) → Widget

Available on Widget, provided by the Animate extension

Visibility-window sugar: animate([], window: from.to(to)) with from defaulting to the window start and to to its end.

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, int wrapWidth = 65}) → 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.

inherited