Swift: Storing states in CoreData with enums

Question

I want to store an enum state for a managed object within CoreData

enum ObjStatus: Int16 {
    case State1 = 0
    case State2 = 1
    case State3 = 3
}

cla         


        

Answer 1

You can extract raw Int16 value with .rawValue property of ObjStatus.

// compare
obj.state == ObjStatus.State1.rawValue

// store
obj.state = ObjStatus.State1.rawValue

But you might want to implement stateEnum accessor for it:

class StateFullManagedObject: NSManagedObject {
    @NSManaged var state: Int16
    var stateEnum:ObjStatus {                    //  ↓ If self.state is invalid.
        get { return ObjStatus(rawValue: self.state) ?? .State1 }
        set { self.state = newValue.rawValue }
    }
}

// compare
obj.stateEnum == .State1

// store
obj.stateEnum = .State1

// switch
switch obj.stateEnum {
case .State1:
    //...
case .State2:
    //...
case .State3:
    //...
}

Answer 2

You can declare your enum as @objc. Then it all automagically works. Here's a snippet from a project I'm working on.

// Defined with @objc to allow it to be used with @NSManaged.
@objc enum AgeType: Int32
{
    case Age                = 0
    case LifeExpectancy     = 1
}

/// The age type, either Age or LifeExpectancy.
@NSManaged var ageType: AgeType

In the Core Data model, ageType is set to type Integer 32.