Assume two unrelated classes (from Flutter libraries, etc):
class A {
String name;
}
class B {
int age;
}
Is it possible to have a List<A/B>? I know it's possible to have List<dynamic> but that would allow for Cs, Ds and Zs to be accepted as well.
You can create a parent abstract class for A and B and add a List which only allows children from the parent class.
abstract class Foo {
}
class A extends Foo {
}
class B extends Foo {
}
class C {
}
This is correct:
List<Foo> items = [A(), B()];
This isn't
List<Foo> items = [A(), B(),C()];
And you can identify the type with your own variable or using the runtimeType
for(Foo item in items){
print(item.runtimeType);
}
Another option (long version)
class Bar {
final A a;
final B b;
Bar({this.a, this.b}) {
if (a == null && b == null || a != null && b != null) throw ArgumentError("only one object is allowed");
}
}
class A {
}
class B {
}
class C {
}
Usage
List<Bar> items = [Bar(a: A()), Bar(b: B())];
for(Bar item in items){
if (item.a != null) print("Item : ${item.a}");
if (item.b != null) print("Item : ${item.b}");
}