StatelessWidget

A StatelessWidget describes UI that doesn't change over time, given the same inputs, it always looks the same.

Example: a reusable stateless widget

class GreetingCard extends StatelessWidget {
  final String name;
  const GreetingCard({super.key, required this.name});

  @override
  Widget build(BuildContext context) {
    return Text('Hello, $name!');
  }
}

Defines a reusable widget that displays "Hello, {name}!", e.g. GreetingCard(name: 'Ada') renders "Hello, Ada!".

You define it as a class extending StatelessWidget, and override its build() method to return the widget tree. Notice name is declared final, from the Dart tutorial's Variables lesson, since a stateless widget's data, by definition, never changes after it's built.