DirectAbsoluteItem class

A widget that positions its child absolutely within a layout container.

AbsoluteItem allows you to position a child widget at specific coordinates relative to its parent's bounds, similar to CSS absolute positioning. The child is removed from the normal document flow and positioned using the top, left, bottom, and right properties.

Usage

LayoutBoxWidget(
  children: [
    AbsoluteItem(
      top: PositionUnit.fixed(20),
      left: PositionUnit.fixed(30),
      width: SizeUnit.fixed(100),
      height: SizeUnit.fixed(50),
      child: Container(color: Colors.red),
    ),
  ],
)

Positioning

The positioning properties work similarly to CSS:

  • top: Distance from the parent's top edge
  • left: Distance from the parent's left edge
  • bottom: Distance from the parent's bottom edge
  • right: Distance from the parent's right edge

You can use any combination of these properties. If both top and bottom are specified, the height is determined by the difference. The same applies to left and right for width.

Sizing

Paint Order

The paintOrder property controls the drawing order when multiple absolutely positioned items overlap. Lower values are painted first.

Inheritance
Implemented types

Constructors

DirectAbsoluteItem.new({Key? key, int? paintOrder, SizeUnit? width, SizeUnit? height, SizeUnit? minWidth, SizeUnit? maxWidth, SizeUnit? minHeight, SizeUnit? maxHeight, PositionUnit? top, PositionUnit? left, PositionUnit? bottom, PositionUnit? right, double? aspectRatio, bool needLayoutBox = false, required Widget child})
Creates an absolutely positioned item with the specified properties.
const

Properties

aspectRatio → double?
The aspect ratio constraint (width/height) for this item.
final
bottom → PositionUnit?
The offset from the bottom edge of the parent container.
final
child → Widget
The widget below this widget in the tree.
finalinherited
debugTypicalAncestorWidgetClass → Type
The typical ancestor widget class for this widget.
no setteroverride
debugTypicalAncestorWidgetDescription → String
Describes the RenderObjectWidget that is typically used to set up the ParentData that applyParentData will write to.
no setterinherited
hashCode → int
The hash code for this object.
no setterinherited
height → SizeUnit?
The height of the absolutely positioned item.
final
key → Key?
Controls how one widget replaces another widget in the tree.
finalinherited
left → PositionUnit?
The offset from the left edge of the parent container.
final
maxHeight → SizeUnit?
The maximum height constraint for this item.
final
maxWidth → SizeUnit?
The maximum width constraint for this item.
final
minHeight → SizeUnit?
The minimum height constraint for this item.
final
minWidth → SizeUnit?
The minimum width constraint for this item.
final
needLayoutBox → bool
final
paintOrder → int?
The paint order for this absolutely positioned item.
final
The offset from the right edge of the parent container.
final
runtimeType → Type
A representation of the runtime type of the object.
no setterinherited
top → PositionUnit?
The offset from the top edge of the parent container.
final
width → SizeUnit?
The width of the absolutely positioned item.
final

Methods

applyParentData(RenderObject renderObject) → void
Applies the absolute positioning configuration to the child's parent data.
override
createElement() → ParentDataElement<LayoutBoxParentData>
Inflates this configuration to a concrete instance.
inherited
debugCanApplyOutOfTurn() → bool
Whether the ParentDataElement.applyWidgetOutOfTurn method is allowed with this widget.
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
debugIsValidRenderObject(RenderObject renderObject) → bool
Checks if this widget can apply its parent data to the provided renderObject.
inherited
noSuchMethod(Invocation invocation) → dynamic
Invoked when a nonexistent 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, 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