How can I populate a tableView using NSSet? (Fast)
I have a Person class in tableView1, then in TableView2 the user adds brands to communicate with the person. My fetch query is trying to return the person they selected and populate the tableView rows with that person's respective brands, but I'm stuck here:
override func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCellWithIdentifier(Storyboard.CellReuseIdentifier, forIndexPath: indexPath) as! UITableViewCell
let brandSetAllObjects = brandSet?.allObjects
let brand = brandSetAllObjects as? Brand[indexPath.row]
cell.textLabel!.text = brand.valueForKey("name") as? String
return cell
}
Fetch:
//Helper Function to Fetch Core Data
func fetchCoreData() {
//1
let appDelegate =
UIApplication.sharedApplication().delegate as! AppDelegate
let managedContext = appDelegate.managedObjectContext!
//2
let fetchRequest = NSFetchRequest(entityName:"Person")
//3
var error: NSError?
let fetchedResults =
managedContext.executeFetchRequest(fetchRequest,
error: &error) as? [NSManagedObject]
if let results = fetchedResults as? [Person] {
for selectedPerson in results {
brandSet = selectedPerson.brands
println(brandSet)
}
} else {
println("Could not fetch \(error), \(error!.userInfo)")
}
classes:
import Foundation
import CoreData
class Brand: NSManagedObject {
@NSManaged var name: String
@NSManaged var people: NSSet
}
import Foundation
import CoreData
class Person: NSManagedObject {
@NSManaged var name: String
@NSManaged var brands: NSSet
func addBrandsObject(value: Brand) {
self.mutableSetValueForKey("brands").addObject(value)
}
}
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Is there a specific sort order that you want to display in the table view?
Instead of directly accessing the data structure, " Brand
" you can have a data manager that treats the data in a consistent manner. You can store all the information Brand
in NSSet
, and then have a method in your data manager that returns NSArray
(possibly called brandArray
). The data manager could take the contents NSSet
, add them to an array, and then sort the array so that they are in uniform order, and return that array.
On the side, UITableView
just replace Brand[indexPath.row]
with something like dataManager.brandArray[indexPath.row]
.
My suggestion for the data manager would be to make the class to be implemented as a singleton . Step 4 of this tutorial explains quite well how to set up the Data Manager.
Side note: the data manager is just a concept, not a strict class or object type. It can be any object that manipulates data, although it is usually run as a singleton that can be accessed from any other class in your project.
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