PositionedModifier class

A widget that controls where a child of a Stack is positioned.

A Positioned widget must be a descendant of a Stack, and the path from the Positioned widget to its enclosing Stack must contain only StatelessWidgets or StatefulWidgets (not other kinds of widgets, like RenderObjectWidgets).

If a widget is wrapped in a Positioned, then it is a positioned widget in its Stack. If the top property is non-null, the top edge of this child will be positioned top layout units from the top of the stack widget. The right, bottom, and left properties work analogously.

If both the top and bottom properties are non-null, then the child will be forced to have exactly the height required to satisfy both constraints. Similarly, setting the right and left properties to non-null values will force the child to have a particular width. Alternatively the width and height properties can be used to give the dimensions, with one corresponding position property (e.g. top and height).

If all three values on a particular axis are null, then the Stack.alignment property is used to position the child.

If all six values are null, the child is a non-positioned child. The Stack uses only the non-positioned children to size itself.

See also:

• AnimatedPositioned, which automatically transitions the child's position over a given duration whenever the given position changes.
• PositionedTransition, which takes a provided Animation to transition changes in the child's position over a given duration.
• PositionedDirectional, which adapts to the ambient Directionality.

Inheritance

• Object
• DiagnosticableTree
• Widget
• StatelessWidget
• SingleChildStatelessModifier
• PositionedModifier

Available extensions

• ModifierTransformer

Constructors

PositionedModifier({Key? key, Widget? child, double? left, double? top, double? right, double? bottom, double? width, double? height})

Creates a widget that controls where a child of a Stack is positioned.

const

PositionedModifier.directional({Key? key, Widget? child, required TextDirection textDirection, double? start, double? top, double? end, double? bottom, double? width, double? height})

Creates a widget that controls where a child of a Stack is positioned.

factory

PositionedModifier.fill({Key? key, Widget? child, double? left = 0.0, double? top = 0.0, double? right = 0.0, double? bottom = 0.0})

Creates a Positioned object with left, top, right, and bottom set to 0.0 unless a value for them is passed.

const

PositionedModifier.fromRect({Key? key, Widget? child, required Rect rect})

Creates a Positioned object with the values from the given Rect.

PositionedModifier.fromRelativeRect({Key? key, Widget? child, required RelativeRect rect})

Creates a Positioned object with the values from the given RelativeRect.

Properties

bottom → double?

The distance that the child's bottom edge is inset from the bottom of the stack.

final

hashCode → int

The hash code for this object.

no setter, inherited

height → double?

The child's height.

final

key → Key?

Controls how one widget replaces another widget in the tree.

final, inherited

left → double?

The distance that the child's left edge is inset from the left of the stack.

final

modifierKey → Key?

The actual key of the widget, which Modifier wrapped

final, inherited

right → double?

The distance that the child's right edge is inset from the right of the stack.

final

runtimeType → Type

A representation of the runtime type of the object.

no setter, inherited

top → double?

The distance that the child's top edge is inset from the top of the stack.

final

width → double?

The child's width.

final

Methods

build(BuildContext context) → Widget

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

inherited

buildWithChild(BuildContext context, Widget? child) → Widget

A build method that receives an extra child parameter.

override

createElement() → SingleChildStatelessElement

Create a SingleChildStatelessElement

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

modified() → Modifier

Available on Widget, provided by the ModifierTransformer extension

Transform normal widget to Modifier

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