由于冗余数据，我需要为我的iOS应用重新组织我的解决方案

Question

I realized I'm not approaching this correctly when I have 3 copies of the same object, so I need some guidance towards structuring this problem. I'll do my best to explain the model at the moment. For simplicity VC = View Controller

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Tl;dr:

MainVC -> MapVC -> DetailsVC <- FavoritesVC
 Tab1                              Tab2

MyClass objects consist of a 'favorite' bool flag and a unique id String
MainVC makes array of MyClass, gives array to MapVC after construction
MapVC constructs dict mapping Pins to MyClass, user selects pin, corresponding 
    MyClass sent to DetailsVC in segue
DetailsVC gets copy of MyClass object, displays its details, can mark as favorite
Since marking as favorite occurs on the copied object, MapVC doesn't realize it's
    marked as favorite

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It starts with the MainVC . This has a container view, which switches between a MapVC and a TableVC (we'll focus on the MapVC). The MainVC uses an XML parser object to sort through a response and create custom MyClass objects and appends them to

myList //(an array of MyClass)

The MapVC also has an array of MyClass called mapList. When MainVC is done updating myList, it also sets

mapPage.mapList = myList

MapVC also has a dictionary that maps Pins to MyClass, so that when a user selects a pin I can see which MyClass it corresponds to.

The map sends the selected MyClass to the DetailsVC in a segue as such

override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
    if let dest = segue.destinationViewController as? DetailsTableViewController{
        dest.myobject = mapList[selectedRow]
        // selectedRow is correctly set elsewhere, no bugs
    }
}

The DetailsVC (which only knows about the single selected myObject) displays the passed (or rather copied) object's details. You can then mark it as a favorite, which sets the object's favorite flag to true. To save favorites, I store a dictionary of MyClass objects that have been marked as favorite to UserDefaults. I use a dictionary instead of an array so I can look up and remove myObjects when a user unfavorites them

var faveArray = [String : MyClass]()
    if let unarchivedObject = NSUserDefaults.standardUserDefaults().objectForKey(Constants.PreferenceKeys.favorites) as? NSData {
        faveArray = NSKeyedUnarchiver.unarchiveObjectWithData(unarchivedObject) as! [String : MyClass]
    }
    if isFavorite{
        faveArray[myobject.id] = myobject
    }
    else{
        faveArray.removeValueForKey(myobject.id)
    }
    defaults.setObject(NSKeyedArchiver.archivedDataWithRootObject(faveArray as NSDictionary), forKey: Constants.PreferenceKeys.favorites)

The FavoritesVC loads the UserDefault dictionary and shows each myObject in a table view. You can also select a myObject here, which will segue to the same DetailsVC where they can unfavorite/refavorite continuously (the favorite button updates instantly, so if you favorite, it turns into unfavorite).

The problem is that when they unfavorite something from the FavoritesVC, it's a different copy MyClass object than the one sitting in the MapVC (same object, different copies), so when you go back to the map it still says "Unfavorite". The broader issue is that I have 3 of the same MyClass lists, 2 dictionaries, and 3 copies of the same MyClass object (1 in MapVC, 1 in ListVC, 1 in FavoritesVC) and I realize this isn't good

I'm thinking of moving all of the data objects to a static class (is that even possible?) so that all controllers have access to the same MyClass array and objects. Is there a better or standard approach?

Answer 1

What you want is a singleton. This is an instance of a class, that is initialized once and, when accessed, is the same instance (stored in the same block of memory, and the equivalent of a static instance). There are multiple singleton patterns, and as I mentioned in my comment, if you want to not accept my answer and simply ask about singletons in Swift, that is okay! It's an open question. Here is an example of the singleton pattern I use, for a MyClass, class:

private let mySingleton = MyClass()

class MyClass {

    class var shared : MyClass {
        return mySingleton
    }
}

Add properties, etc... to this class, of course. To access the SAME instance of this class in any VC, use the following code:

let globalMyClass = MyClass.shared

That's it! Obviously, name your class and var whatever you like. And again, there is another solid approach to global vars in Swift. Use this for now, but learn when you have time. Good luck!