Using enum as property of Realm model

66

votes

Is it possible to use an Enum as a property for my model? I currently have a class like this:

class Checkin: RLMObject {
  dynamic var id: Int = 0
  dynamic var kind: String = "checked_in"
  var kindEnum: Kind = .CheckedIn {
    willSet { self.kind = newValue.rawValue }
  }

  enum Kind: String {
    case CheckedIn = "checked_in"
    case EnRoute = "en_route"
    case DroppedOff = "dropped_off"
  }
  ....
}

It works okay, but I'd like to be able to have the kind property be the Enum and have Realm automatically call .rawValue on the property when it is saving an object to the store. Is this possible in Realm or is there a feature request already out there for it?

iosenumsrealm

95

votes

You should override your kindEnum's setter and getter for this case:

enum Kind: String {
  case CheckedIn
  case EnRoute
  case DroppedOff
}

class Checkin: Object {
  @objc dynamic var id = 0
  var kind = Kind.CheckedIn.rawValue
  var kindEnum: Kind {
    get {
      return Kind(rawValue: kind)!
    }
    set {
      kind = newValue.rawValue
    }
  }
}

51

votes

I've refined this model a little further.

enum Thing: String {
    case Thing1
    case Thing2
    case Thing3
}

then in my Realm class object:

class myClass : Object {
    private dynamic var privateThing = Thing.Thing1.rawValue
    var thing: Thing {
        get { return Thing(rawValue: privateThing)! }
        set { privateThing = newValue.rawValue }
    }
}

This allows us to write

myClassInstance.thing = .Thing1

(storing "Thing1" into privateThing), but prevents typing of

myClassInstance.privateThing = "Thing4"

which is not a valid value so preserving data integrity.

20

votes

Since Realm support Objective-C enums and they are representable by Int you can use this:

class Checkin: Object {
  dynamic var id: Int = 0
  dynamic var kind: Kind = .checkedIn

  @objc enum Kind: Int {
    case checkedIn
    case enRoute
    case droppedOff
  }
  ....
}

If you need to parse to/from String you can use a custom initializer for Kind and an toString function.

There is a discussion about this in GitHub

This works with Swift 3.0 and Realm 2.0.2

12

votes

Diogo T's solution worked before recent updates of RealmSwift. Eventually we now have to conform to RealmEnum protocol to be able to be a managed property of Realm Object.

@objc enum MyEnum: Int, RealmEnum {
    ...
}

Or add below in some place:

extension MyEnum: RealmEnum { }

RealmSwift documentation for it

0

votes

Example with RealmEnum and RealmOptional

@objc enum MyEnum: Int, RealmEnum {
    case first
    case second
}

final class MyEntry: Object {
    //It should be let
    let someVariable = RealmOptional<CRUD>()
}

//using
myEntry.someVariable.value = MyEnum.first

0

votes

Alternate solution to avoid the force un-wrap get { return Thing(rawValue: privateThing)! }

enum Kind: String, CaseIterable {
      case CheckedIn
      case EnRoute
      case DroppedOff
    }

    @objc dynamic var kindRaw = Kind.CheckedIn.rawValue
    var kind: Kind {
        get {
            for kind in Kind.allCases where kindRaw == kind.rawValue {
                return kind
            }
            return .CheckedIn //default
        }
        set {
            kindRaw = newValue.rawValue
        }
    }

Using enum as property of Realm model

6 Answers