我可以在Realm Swift中使用异构集合吗？

Question

I would like to have an object that is an ordered collection of multiple different kinds of Realm Objects, like so...

public class One: Object {
    dynamic var name = ""
}

public class Two: Object {
    dynamic var label = ""
}

public class Listing: Object {
    let onesAndTwos = List<Object>()
}

Is there an elegant way to do this?

I know I can add an Enum-like wrapper object...

public class OneOrTwo: Object {
    dynamic var one: One?
    dynamic var two: Two?
}

public class Listing: Object {
    let onesAndTwos = List<OneOrTwo>()
}

But I'd like to avoid that indirection, if possible.

Answer 1

List<T> property can't contain objects of different types.

Please learn more in docs at https://realm.io/docs/swift/latest/#relationships and https://realm.io/docs/swift/latest/#model-inheritance , that should explain why it's not possible.

So I suggest you to use composition over inheritance, basically the same way as you mentioned in your post.