CustomBoxy class abstract

A widget that uses a delegate to control the layout of multiple children.

This is essentially a more powerful version of CustomMultiChildLayout, it allows you to inflate, constrain, and lay out each child manually, it also allows the size of the widget to depend on the layout of its children.

In most cases this is overkill, you may want to check if some combination of Stack, LayoutBuilder, CustomMultiChildLayout, and Flow is more suitable.

Boxy supports both sliver and box render protocols for its own RenderObject, and arbitrary children. Which protocols you use is going to affect the constructor and delegate to implement.

• Use the default constructor and BoxyDelegate to create a RenderBox that only has RenderBox children.
• Use the CustomBoxy.box constructor and BoxBoxyDelegate to implement a RenderBox with any child type.
• Use the CustomBoxy.sliver constructor and SliverBoxyDelegate to implement a RenderSliver with any child type.

When implementing a BoxBoxyDelegate or SliverBoxyDelegate, delegates can access BoxyChild and SliverBoxyChild wrappers by passing type arguments to BaseBoxyDelegate.getChild, for example:

final box = getChild<BoxyChild>(#box);
final sliver = getChild<SliverBoxyChild>(#sliver);

Children can be given an id using BoxyId, otherwise they are given an incrementing int id in the provided order, for example:

CustomBoxy(
  delegate: MyBoxyDelegate(),
  children: [
    Container(color: Colors.red)), // Child 0
    BoxyId(id: #green, child: Container(color: Colors.green)),
    Container(color: Colors.green)), // Child 1
  ],
);

See also:

• BoxyDelegate, used with the default constructor.
• BoxBoxyDelegate, used with CustomBoxy.box.
• SliverBoxyDelegate, used with CustomBoxy.sliver.

Inheritance

• Object
• DiagnosticableTree
• Widget
• RenderObjectWidget
• LayoutInflatingWidget
• CustomBoxy

Constructors

CustomBoxy({Key? key, required BoxyDelegate<Object> delegate, List<Widget> children})

Constructs a CustomBoxy with BoxyDelegate that can manage BoxyChild children.

const

factory

CustomBoxy.box({Key? key, required BoxBoxyDelegate<Object> delegate, List<Widget> children, InflatedChildHandleFactory childFactory})

Constructs a CustomBoxy with BoxBoxyDelegate that can manage both BoxyChild and SliverBoxyChild children.

const

factory

CustomBoxy.sliver({Key? key, required SliverBoxyDelegate<Object> delegate, List<Widget> children, InflatedChildHandleFactory childFactory})

Constructs a CustomBoxy with SliverBoxyDelegate that can manage both BoxyChild and SliverBoxyChild children.

const

factory

Properties

childFactory → InflatedChildHandleFactory

Factory function that constructs an appropriate BaseBoxyChild based on the the generic type argument.

final

children → List<Widget>

The list of children this boxy is a parent of.

final, inherited

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

Methods

createElement() → InflatingElement

RenderObjectWidgets always inflate to a RenderObjectElement subclass.

inherited

createRenderObject(BuildContext context) → RenderObject

Creates an instance of the RenderObject class that this RenderObjectWidget represents, using the configuration described by this RenderObjectWidget.

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

didUnmountRenderObject(covariant RenderObject renderObject) → void

A render object previously associated with this widget has been removed from the tree. The given RenderObject will be of the same type as returned by this object's createRenderObject.

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}) → 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

updateRenderObject(BuildContext context, covariant RenderObject renderObject) → void

Copies the configuration described by this RenderObjectWidget to the given RenderObject, which will be of the same type as returned by this object's createRenderObject.

inherited

Operators

operator ==(Object other) → bool

The equality operator.

inherited

Static Methods

defaultChildFactory<T extends InflatedChildHandle>({required Object id, required InflatingRenderObjectMixin<RenderObject, InflatingParentData<RenderObject>, InflatedChildHandle> parent, RenderObject? render, Element? context, Widget? widget}) → T

The default child handle factory for BaseBoxyChild subclasses, constructs an appropriate child based on the the generic type argument.