FlexItem class abstract interface

A widget that configures flex properties for an individual child within a FlexBox.

FlexItem is used to wrap children of a FlexBox to specify how each child should behave within the flex layout. It provides control over sizing, positioning, flex behavior, and alignment for each individual item.

This widget works by attaching LayoutData to the child's ParentData, which the flex layout algorithm uses to determine how to size and position each child.

Example usage:

FlexBox(
  direction: FlexDirection.row,
  children: [
    FlexItem(
      flexGrow: 1.0,
      child: Container(color: Colors.red),
    ),
    FlexItem(
      width: SizeUnit.fixed(100),
      child: Container(color: Colors.blue),
    ),
  ],
)

Implemented types

• LayoutItem

Implementers

• BuilderFlexItem
• DirectFlexItem

Available extensions

• WidgetExtension

Constructors

FlexItem({Key? key, int? paintOrder, SizeUnit? width, SizeUnit? height, SizeUnit? minWidth, SizeUnit? maxWidth, SizeUnit? minHeight, SizeUnit? maxHeight, double flexGrow, double flexShrink, double? aspectRatio, PositionUnit? top, PositionUnit? left, PositionUnit? bottom, PositionUnit? right, BoxAlignmentGeometry? alignSelf, PositionType? position, required Widget child})

Creates a flex item with a direct child widget and specified flex properties.

const

factory

FlexItem.builder({Key? key, int? paintOrder, SizeUnit? width, SizeUnit? height, SizeUnit? minWidth, SizeUnit? maxWidth, SizeUnit? minHeight, SizeUnit? maxHeight, double flexGrow, double flexShrink, double? aspectRatio, PositionUnit? top, PositionUnit? left, PositionUnit? bottom, PositionUnit? right, BoxAlignmentGeometry? alignSelf, PositionType? position, required Widget builder(BuildContext context, LayoutBox box)})

Creates a flex item with a builder function for dynamic child construction.

const

factory

Properties

alignSelf → BoxAlignmentGeometry?

The cross-axis alignment for this specific flex item.

no setter

asAbsoluteItem → Widget

Available on Widget, provided by the WidgetExtension extension

Explicitly wraps this widget as an AbsoluteItem.

no setter

asFlexItem → Widget

Available on Widget, provided by the WidgetExtension extension

Explicitly wraps this widget as a FlexItem.

no setter

aspectRatio → double?

The aspect ratio constraint (width/height) for this item.

no setter, inherited

bottom → PositionUnit?

The offset from the bottom edge of the parent container.

no setter, inherited

flexGrow → double

The flex grow factor for this item.

no setter

flexShrink → double

The flex shrink factor for this item.

no setter

hashCode → int

The hash code for this object.

no setter, inherited

height → SizeUnit?

The preferred height of this item.

no setter, inherited

key → Key?

Controls how one widget replaces another widget in the tree.

final, inherited

left → PositionUnit?

The offset from the left edge of the parent container.

no setter, inherited

maxHeight → SizeUnit?

The maximum height constraint for this item.

no setter, inherited

maxWidth → SizeUnit?

The maximum width constraint for this item.

no setter, inherited

minHeight → SizeUnit?

The minimum height constraint for this item.

no setter, inherited

minWidth → SizeUnit?

The minimum width constraint for this item.

no setter, inherited

paintOrder → int?

The paint order for this item, controlling drawing order when overlapping. Lower values are painted first (behind), higher values are painted last (on top).

no setter, inherited

position → PositionType?

The positioning type for this flex item.

no setter

right → PositionUnit?

The offset from the right edge of the parent container.

no setter, inherited

runtimeType → Type

A representation of the runtime type of the object.

no setter, inherited

top → PositionUnit?

The offset from the top edge of the parent container.

no setter, inherited

width → SizeUnit?

The preferred width of this item.

no setter, inherited

Methods

aspectRatio(double aspectRatio, [Key? key]) → Widget

Available on Widget, provided by the WidgetExtension extension

Sets the aspect ratio constraint for this widget.

bottom(PositionUnit bottom, [Key? key]) → Widget

Available on Widget, provided by the WidgetExtension extension

Sets the distance from the bottom edge of the parent container.

constrained({SizeUnit? minWidth, SizeUnit? maxWidth, SizeUnit? minHeight, SizeUnit? maxHeight, Key? key}) → Widget

Available on Widget, provided by the WidgetExtension extension

Sets comprehensive size constraints including both minimum and maximum bounds.

createElement() → Element

Inflates this configuration to a concrete instance.

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

flexGrow(double flexGrow, [Key? key]) → Widget

Available on Widget, provided by the WidgetExtension extension

Sets the flex grow factor for this widget within a flex container.

flexShrink(double flexShrink, [Key? key]) → Widget

Available on Widget, provided by the WidgetExtension extension

Sets the flex shrink factor for this widget within a flex container.

height(SizeUnit height, [Key? key]) → Widget

Available on Widget, provided by the WidgetExtension extension

Sets the height of this widget using a SizeUnit.

id(Object valueKey) → Widget

Available on Widget, provided by the WidgetExtension extension

Assigns a ValueKey to this widget using the provided value.

key(Key key) → Widget

Available on Widget, provided by the WidgetExtension extension

Assigns a Key to this widget.

left(PositionUnit left, [Key? key]) → Widget

Available on Widget, provided by the WidgetExtension extension

Sets the distance from the left edge of the parent container.

maxHeight(SizeUnit maxHeight, [Key? key]) → Widget

Available on Widget, provided by the WidgetExtension extension

Sets the maximum height constraint for this widget using a SizeUnit.

maxSized({SizeUnit? maxWidth, SizeUnit? maxHeight, Key? key}) → Widget

Available on Widget, provided by the WidgetExtension extension

Sets maximum width and height constraints simultaneously.

maxWidth(SizeUnit maxWidth, [Key? key]) → Widget

Available on Widget, provided by the WidgetExtension extension

Sets the maximum width constraint for this widget using a SizeUnit.

minHeight(SizeUnit minHeight, [Key? key]) → Widget

Available on Widget, provided by the WidgetExtension extension

Sets the minimum height constraint for this widget using a SizeUnit.

minSized({SizeUnit? minWidth, SizeUnit? minHeight, Key? key}) → Widget

Available on Widget, provided by the WidgetExtension extension

Sets minimum width and height constraints simultaneously.

minWidth(SizeUnit minWidth, [Key? key]) → Widget

Available on Widget, provided by the WidgetExtension extension

Sets the minimum width constraint for this widget using a SizeUnit.

noSuchMethod(Invocation invocation) → dynamic

Invoked when a nonexistent method or property is accessed.

inherited

paintOrder(int paintOrder, [Key? key]) → Widget

Available on Widget, provided by the WidgetExtension extension

Sets the paint order for this widget within its parent container.

position(PositionType position, [Key? key]) → Widget

Available on Widget, provided by the WidgetExtension extension

Sets the position type for this widget to control positioning context.

positioned({PositionUnit? top, PositionUnit? left, PositionUnit? bottom, PositionUnit? right, Key? key}) → Widget

Available on Widget, provided by the WidgetExtension extension

Positions the widget using multiple edge offsets simultaneously.

right(PositionUnit right, [Key? key]) → Widget

Available on Widget, provided by the WidgetExtension extension

Sets the distance from the right edge of the parent container.

selfAligned(BoxAlignmentGeometry alignSelf, [Key? key]) → Widget

Available on Widget, provided by the WidgetExtension extension

Sets the alignment of this widget within its parent flex container.

sized({SizeUnit? width, SizeUnit? height, Key? key}) → Widget

Available on Widget, provided by the WidgetExtension extension

Sets both width and height dimensions simultaneously.

toDiagnosticsNode({String? name, DiagnosticsTreeStyle? style}) → DiagnosticsNode

Returns a debug representation of the object that is used by debugging tools and by DiagnosticsNode.toStringDeep.

inherited

top(PositionUnit top, [Key? key]) → Widget

Available on Widget, provided by the WidgetExtension extension

Sets the distance from the top edge of the parent container.

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

width(SizeUnit width, [Key? key]) → Widget

Available on Widget, provided by the WidgetExtension extension

Sets the width of this widget using a SizeUnit.

Operators

operator ==(Object other) → bool

The equality operator.

inherited