Making a counter app - Do I have to do something after saving to Core Data? - swift

Question

Trying my hand in Swift and creating my first "app". I'm essentially creating a cookie-clicker clone where you just click an image in the center of your screen repeatedly to increment your score.
I'm experiencing some issues where clicking the image once will increment my score by 1, but upon clicking it again, the score stays 1.
I'm almost positive I'm supposed to do something after saving to CoreData - I just don't know what. Do I have to refresh the View? Sorry for the newbie question
#IBAction func tapHomeImage(sender: AnyObject) {
//Score is the name of my Entity, with "points" being an attribute
let entity = NSEntityDescription.entityForName("Score", inManagedObjectContext: managedObjectContext!)
let score = Score(entity: entity!, insertIntoManagedObjectContext: managedObjectContext!)
// **As an aside question, is there a more efficient way to code the below? The issue I have is that score.points is of type NSNumber
let intScore = score.points as Int
let incrementedIntScore = intScore + 1
score.points = NSNumber(integer: incrementedIntScore)
var error: NSError?
managedObjectContext?.save(&error)
//homeScoreLabel is an IBOutlet for the Score displayed on the page
homeScoreLabel?.text = "\(score.points)"
}
Thank you very much!

Answer 1

You don't need to do anything after saving, you need to do something before calling this method. You need to find an instance of Score that already exists, and use that.
When you get to this line:
let score = Score(entity: entity!, insertIntoManagedObjectContext: managedObjectContext!)
You create a new instance of the Score entity, every time this method runs. So when you do this:
let intScore = score.points as Int
let incrementedIntScore = intScore + 1
score.points = NSNumber(integer: incrementedIntScore)
You're working with a brand new instance every time. The score is initially zero, and you always increase it to 1.
What you should do:
Use a single instance of Score and save that as a property of your view controller. That is, have something like this:
var score: Score?
Assign a value to this property once, when the view controller loads. Since you're saving data, you should use executeFetchRequest to look up a previously-saved instance. If no previous instance exists, then create a new one via insertIntoManagedObjectContext.
Use that instance in this IBAction.
There are other ways to fix the code. The key is to make sure that you use the same instance of Score every time instead of creating a new one at every tap.