BuildableComponent class abstract Components Core

A Component that does not require mutable state.

A BuildableComponent is a component whose output is determined entirely by its configuration and does not hold mutable state. It describes part of the UI purely from its configuration and builds a tree of other components that represent its contents.

The build method is called when the BuildableComponentInstance is created, producing a fixed set of child Components for rendering. Any change in appearance or layout requires creating a new BuildableComponent with updated configuration.

For dynamic or interactive components that depend on internal state, use a StatefulComponent instead.

Example:

class Menu extends BuildableComponent {
  final List<String> items;

  const Menu(this.items);

  @override
  List<Component> build() {
    return items.map((label) => TextComponent(label)).toList();
  }
}

Performance considerations

Because a BuildableComponent has no internal state, it can be reused and rebuilt efficiently. To maximize performance:

  • Use const constructors where possible.
  • Keep the build method minimal, avoiding unnecessary nested components.

See also:

Inheritance

Constructors

BuildableComponent.new()
Creates a stateless, buildable component.
const

Properties

hashCode → int
The hash code for this object.
no setterinherited
padding → EdgeInsets
The padding inside the component’s layout bounds.
finalinherited
position → Position?
The position of the component within its parent or layout.
finalinherited
runtimeType → Type
A representation of the runtime type of the object.
no setterinherited

Methods

build() → List<Component>
Builds and returns the list of child Components for this component.
createInstance() → BuildableComponentInstance
Creates a ComponentInstance that can be rendered.
override
noSuchMethod(Invocation invocation) → dynamic
Invoked when a nonexistent method or property is accessed.
inherited
toString() → String
A string representation of this object.
inherited

Operators

operator ==(Object other) → bool
The equality operator.
inherited