AdaptiveContainer class

A simplified declarative wrapper around ContainerQuery that displays different widgets based on the parent container's size tier.

Unlike screen-based breakpoints, AdaptiveContainer responds to the parent's actual constraints, making it ideal for reusable components that may appear in different-sized containers.

Performance Design

• Uses ContainerQuery internally (single LayoutBuilder per instance)
• Widget selection via array lookup — O(1) fallback chain
• No extra allocations — the widget array is created once per build

Fallback Behavior

If a widget for the current tier is null, falls back to the nearest smaller tier: xxl → xl → lg → md → sm → xs (always available).

Example

AdaptiveContainer(
  breakpoints: [300, 500, 700, 900, 1200],
  xs: CompactProductCard(),
  md: MediumProductCard(),
  lg: ExpandedProductCard(),
)

Inheritance

• Object
• DiagnosticableTree
• Widget
• StatelessWidget
• AdaptiveContainer

Constructors

AdaptiveContainer({Key? key, required Widget xs, Widget? sm, Widget? md, Widget? lg, Widget? xl, Widget? xxl, List<double>? breakpoints})

Creates an AdaptiveContainer.

const

Properties

breakpoints → List<double>?

Custom breakpoints to define when to switch tiers. Must contain up to 5 ascending values mapping to sm/md/lg/xl/xxl. If null, the tier is always QueryTier.xs.

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

lg → Widget?

Optional: Widget for Large containers.

final

md → Widget?

Optional: Widget for Medium containers.

final

runtimeType → Type

A representation of the runtime type of the object.

no setter, inherited

sm → Widget?

Optional: Widget for Small containers.

final

xl → Widget?

Optional: Widget for Extra Large containers.

final

xs → Widget

The default widget (Extra Small). Required as the fallback.

final

xxl → Widget?

Optional: Widget for Double Extra Large containers.

final

Methods

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

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