[英]Swift Core Data - Error accessing fetched entity with NSManagedObject Subclass
我正在嘗試獲取核心數據實體,並且遇到一個問題,我認為這是由於我使用了子類NSManagedObject。
嘗試打印獲取的對象之一時,出現以下錯誤:
Thread 1: EXC_BAD_ACCESS (code=1, address=0x0)
這是我的“顯示” NSManagedObject子類:
import Foundation
import CoreData
@objc(Show)
class Show: NSManagedObject {
@NSManaged var dateUpdated: NSDate
@NSManaged var fontFilename: String
@NSManaged var fontName: String
@NSManaged var idShow: NSNumber
@NSManaged var isActive: NSNumber
@NSManaged var productIdentifier: String
@NSManaged var title: String
}
這是我的助手類CoreDataManager.swift中的提取調用:
func fetchShows() -> Array<AnyObject>?
{
// This function will fetch data for all available shows.
// Return value will be an array of dictionaries (i.e. [0]->{Show, Characters})
// i.e. Show Title, Store Product Identifier, Font, Characters, etc.
var results = Array<AnyObject>()
let context:NSManagedObjectContext = self.managedObjectContext!
var error: NSError?
var fetchRequest = NSFetchRequest()
let entity = NSEntityDescription.entityForName("Show", inManagedObjectContext: context)
fetchRequest.entity = entity
let fetchedObjects = context.executeFetchRequest(fetchRequest, error: &error)! as Array
for item in fetchedObjects
{
var showData = Dictionary<String, AnyObject>()
let show: Show = item as Show
showData.updateValue(show, forKey: "show")
// Get Characters
showData.updateValue(self.fetchCharactersForShow(show.idShow)!, forKey: "characters")
results.append(showData)
// Test
self.printShow(show.idShow) //NOTE - THIS METHOD CREATES A NEW FETCH REQUEST USING THE PROVIDED SHOW ID AND SUCCESSFULLY PRINTS OUT THE SHOW DATA
}
return results
}
這是我現在嘗試從RootViewController.swift獲取的值的地方:
//TESTING
self.shows = CoreDataManager().fetchShows()!
let showData = self.shows[0] as Dictionary<String, AnyObject>
let show = showData["show"] as Show
println("TEST: Show \(show.title) is active: \(show.isActive.boolValue)")
/******/
這是“ Show”對象的調試器的屏幕截圖:
哇,我好笨。 看來問題出在我調用'fetchShows()'方法的方式上。 我實際上需要創建並分配一個“ CoreDataManager”對象,然后使用該對象調用該方法,而不是嘗試僅對類方法進行調用:
let DataManager = CoreDataManager()
self.shows = DataManager.fetchShows()
現在就可以了!
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