Parse - Subclassing with Swift?

Question

I'm trying to get a standard subclassing to work with swift.

Bridging-Header.h

#import <Parse/Parse.h>
#import <Parse/PFObject+Subclass.h>
#import <Parse/PFGeoPoint.h>

Subclass

class Event: PFObject, PFSubclassing {

    class func parseClassName() -> String! {
        return "Event"
    }

    override class func load() {
        registerSubclass()
    }
}

getting a compile error saying that Event does not conform to PFSubclassing.

Any suggestions?

Answer 1

Check out my Parse Subclass generator GSParseSchema. It can generate the Swift and Objective-C classes for you.

In Swift, you'll want to override the initialize function.

override class func initialize() {
    struct Static {
        static var onceToken : dispatch_once_t = 0;
    }
    dispatch_once(&Static.onceToken) {
        self.registerSubclass()
    }
}

I've found this auto-registration to not always work, so I also explicitly register the subclasses in my AppDelegate. Be sure you register you before you initialize Parse with setApplicationId:clientKey:

Event.registerSubclass()

Answer 2

Check out this thread. Here is an explanation of the problem:

I already opened a bug to Parse about this point. Basically the issue is with the Parse header files where the protocol definition inside PFSubclassing.h defines this method in this way: + (instancetype)objectWithoutDataWithObjectId:(NSString )objectId; but then the same method is implemented by PFObject+Subclass.h in this way (notice the difference: instancetype --> id) + (id)objectWithoutDataWithObjectId:(NSString )objectId; This is enough for Swift to complain. The only solution I found is to directly change the header in the framework definition by replacing "id" with "instancetype". If you do this, the code will compile.

So, here's your solution, and it's worked for me; I had the same problem:

• Open PFSubclassing.h (note that this is the PFSubclassing.h under your Parse directory)
• Find the objectWithoutDataWithObjectId: method
• Replace the method signature with: (id)objectWithoutDataWithObjectId:(NSString *)objectId;

Answer 3

For the latest version of Parse 1.9.1 and Swift 2.1, then the following applies:

• No need to show that the class conforms to the protocol PFSubclassing, the following is enough

class Event : PFObject { // code }

• If you use pods then you dont need to include Parse, PFSubclassing everywhere

A example can look like the following:

class Event: PFObject {

// @NSManaged gives you autosuggest and type check
@NSManaged var var1: String? 
@NSManaged var var2: String?

override class func initialize() {
    struct Static {
        static var onceToken : dispatch_once_t = 0;
    }
    dispatch_once(&Static.onceToken) {
        self.registerSubclass()
    }
  }
}

I will try your class generator, feels like I can save a lot of time there. Have been researching the best way to map Swift objects to Parse. I built my structure from a UML Class Diagram and added the relations set in the Parse DB to the diagram. Not best practice though it gives me what I need.

Going to use your generator, and design it as 4 tier with 4th tier being Parse DB and tier 3-1 being MVC, with M generated with your code and the needed logic from the UML Class diagram.