CustomBoxy class Null safety

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.

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:

Inheritance

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. [...]
@nonVirtual, read-only, 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.
read-only, 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. [...]
@factory, @protected, inherited
debugDescribeChildren() List<DiagnosticsNode>
Returns a list of DiagnosticsNode objects describing this node's children. [...]
@protected, 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.
@protected, inherited
noSuchMethod(Invocation invocation) → dynamic
Invoked when a non-existent 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. [...]
@protected, inherited

Operators

operator ==(Object other) bool
The equality operator. [...]
@nonVirtual, inherited

Static Methods

defaultChildFactory<T extends InflatedChildHandle>({required Object id, required InflatingRenderObjectMixin<RenderObject, InflatingParentData<RenderObject>, InflatedChildHandle> parent, RenderObject? render, Widget? widget}) → T
The default child handle factory for BaseBoxyChild subclasses, constructs an appropriate child based on the the generic type argument.