StatefulComponentInstance class

Runtime instance of a StatefulComponent.

A StatefulComponentInstance owns and manages the ComponentState for its StatefulComponent, builds its child components, and coordinates their layout and rendering.

Responsibilities:

• Initialize and hold a single ComponentState instance.
• Build and cache child ComponentInstances.
• Rebuild children when requested by the state.
• Perform layout measurement via fitWidth, fitHeight, and measure.
• Render children to a CanvasBuffer.

Lifecycle:

• Created from a StatefulComponent.
• Lazily creates the state when state is first accessed.
• rebuild replaces the child component tree using ComponentState.build.

See also:

• StatefulComponent — defines the component’s configuration.
• ComponentState — holds mutable state and triggers rebuilds.
• ParentComponentInstance — base class for components with children.

Inheritance

• Object
• ComponentInstance
• ParentComponentInstance
• StatefulComponentInstance

Constructors

StatefulComponentInstance(StatefulComponent component)

Creates a new StatefulComponentInstance for the given component.

Properties

bounds ↔ Rect

The current layout bounds for this component instance.

getter/setter pair, inherited

childGap → int

Vertical spacing between children when laid out.

final

children ← List<Component>

Replaces the list of child components without building them.

no getter

childrenInstance → List<ComponentInstance>

Returns the list of runtime child instances.

no setter, override

component → StatefulComponent

The configuration for this component instance.

final

direction → Axis

The primary axis along which children are laid out. Defaults to vertical stacking.

no setter, inherited

hashCode → int

The hash code for this object.

no setter, inherited

padding → EdgeInsets

The padding inside the component’s allocated space.

final, inherited

position → Position

The position of this component relative to its parent or container.

final, inherited

renderManager ↔ RenderManager?

The render manager that may schedule renders for this instance.

getter/setter pair

runtimeType → Type

A representation of the runtime type of the object.

no setter, inherited

state → ComponentState<StatefulComponent>

Lazily initializes and returns this component’s state.

no setter

Methods

fitHeight() → int

Calculates the total height required to fit all children, including the childGap between them.

override

fitWidth() → int

Calculates the maximum width required to fit all children.

override

measure(Size maxSize) → Size

Measures the size this component would take given maxSize.

override

noSuchMethod(Invocation invocation) → dynamic

Invoked when a nonexistent method or property is accessed.

inherited

rebuild() → void

Rebuilds the child component list from the current state.

render(CanvasBuffer buffer, Rect bounds) → void

Renders all children into the given buffer within bounds.

override

shouldRenderChild(ComponentInstance child) → bool

Determines whether a given child should be rendered. Defaults to false, meaning the decision is left to layout/rendering code.

inherited

toString() → String

A string representation of this object.

inherited

Operators

operator ==(Object other) → bool

The equality operator.

inherited