enum Flutter 3
/// Adding members
/// With enhanced enums, you can add any member to your enum as long as the constructor is const.
/// This also means that you can add getters or methods to existing enums, for example:
enum Cake {
cherry,
apple,
strawberry;
String get description => '$name cake';
}
/// Generics
/// Enhanced enum classes also enable you to use generics for you enums. If you combine this with members, you can do the following:
enum Bar<T extends Object> {
number<int>(42),
name<String>('creativecreatorormaybenot'),
baz(true); // Note that type inference also works.
const Bar(this.value);
final T value;
}
/// Mixins and interfaces
/// In addition to declaring members, you can also mixin mixins and implement interfaces with enhanced enums and override any missing implementations.
mixin Foo {
int get n;
}
abstract class Bar {
void printNumber();
}
enum Baz with Foo implements Bar {
one(1),
two(2);
const Baz(this.n);
@override
final int n;
@override
void printNumber() => print(n);
}
/// Multiple arguments
/// Finally note that even if I did not make use of it in any of the examples above, it is possible to have an arbitrary number of arguments (and an initializer list):
enum Foo {
bar(42, description: 'The answer to life, the universe, and everything.'),
baz(0, enabled: false, description: 'noop');
const Foo(
int number, {
this.enabled = true,
required this.description,
}) : n = number;
final int n;
final bool enabled;
final String description;
}
Perfect Pollan
