我一直在努力让Core Data在我的移动应用程序中运行。在我尝试修复它之后，这些值始终保持为零。这是保存我的信息的相关信息，请注意，在任何时间点只会有一个结果。
var appDel:AppDelegate = (UIApplication.sharedApplication().delegate as AppDelegate)
var context:NSManagedObjectContext = appDel.managedObjectContext!
let insertBools = NSEntityDescription.insertNewObjectForEntityForName("Codes", inManagedObjectContext: context) as NSManagedObject
稍后在代码中根据扫描的QR码进行字符串检查比较...
else if (metadataObj.stringValue == "oiu2162poiu" && res.qrCode5_Found != true) {
captureSession?.stopRunning()
println("\(metadataObj.stringValue) qrCode5_Found if")
insertBools.setValue(true, forKey: "qrCode5_Found")
var alert = UIAlertController(title: "Code Found!", message: "You have found and scanned Code #5!", preferredStyle: UIAlertControllerStyle.Alert)
alert.addAction(UIAlertAction(title: "OK", style: UIAlertActionStyle.Default, handler: nil))
self.presentViewController(alert, animated: true, completion: nil)
insertBools.managedObjectContext?.save(nil)
self.navigationController?.popViewControllerAnimated(false)
}
我不确定我哪里出错了。之前的View控制器在每次加载时检索每个键的值，并根据是否找到某些元素显示某些标签（这是应用程序的清道夫风格部分）。
override func viewDidLoad() {
super.viewDidLoad()
var appDel:AppDelegate = (UIApplication.sharedApplication().delegate as AppDelegate)
var context:NSManagedObjectContext = appDel.managedObjectContext!
let request = NSFetchRequest(entityName: "Codes")
request.returnsObjectsAsFaults = false
var results:NSArray = context.executeFetchRequest(request, error: nil)!
if (results.count == 1) {
var res = results[0] as Codes
if (res.qrCode1_Found != true) {
qrCode1.enabled = true
scanQRCodeButton.enabled = true
qrLeftList.enabled = true
}
if (res.qrCode2_Found != true) {
qrCode2.enabled = true
scanQRCodeButton.enabled = true
qrLeftList.enabled = true
}
if (res.qrCode3_Found != true) {
qrCode3.enabled = true
scanQRCodeButton.enabled = true
qrLeftList.enabled = true
}
if (res.qrCode4_Found != true) {
qrCode4.enabled = true
scanQRCodeButton.enabled = true
qrLeftList.enabled = true
}
if (res.qrCode5_Found != true) {
qrCode5.enabled = false
scanQRCodeButton.enabled = true
qrLeftList.enabled = true
}
if (res.qrCode5_Found == true && res.qrCode4_Found == true && res.qrCode3_Found == true && res.qrCode2_Found == true && res.qrCode1_Found == true) {
registerButton.enabled = true
scanQRCodeButton.enabled = false
}
}
........
我的AppDelegate文件，我最初并没有包含Core Data，但是我手动导入了它，并且编译器没有抛出任何错误。
//
// AppDelegate.swift
// webview_test
//
// Created by Robert on 3/19/15.
// Copyright (c) 2015 Robert. All rights reserved.
//
import UIKit
import CoreData
@UIApplicationMain
class AppDelegate: UIResponder, UIApplicationDelegate {
var window: UIWindow?
func application(application: UIApplication, didFinishLaunchingWithOptions launchOptions: [NSObject: AnyObject]?) -> Bool {
// Override point for customization after application launch.
return true
}
func applicationWillResignActive(application: UIApplication) {
// Sent when the application is about to move from active to inactive state. This can occur for certain types of temporary interruptions (such as an incoming phone call or SMS message) or when the user quits the application and it begins the transition to the background state.
// Use this method to pause ongoing tasks, disable timers, and throttle down OpenGL ES frame rates. Games should use this method to pause the game.
}
func applicationDidEnterBackground(application: UIApplication) {
// Use this method to release shared resources, save user data, invalidate timers, and store enough application state information to restore your application to its current state in case it is terminated later.
// If your application supports background execution, this method is called instead of applicationWillTerminate: when the user quits.
}
func applicationWillEnterForeground(application: UIApplication) {
// Called as part of the transition from the background to the inactive state; here you can undo many of the changes made on entering the background.
}
func applicationDidBecomeActive(application: UIApplication) {
// Restart any tasks that were paused (or not yet started) while the application was inactive. If the application was previously in the background, optionally refresh the user interface.
}
// MARK: - Core Data stack
lazy var applicationDocumentsDirectory: NSURL = {
// The directory the application uses to store the Core Data store file. This code uses a directory named "com.xxxx.ProjectName" in the application's documents Application Support directory.
let urls = NSFileManager.defaultManager().URLsForDirectory(.DocumentDirectory, inDomains: .UserDomainMask)
return urls[urls.count-1] as NSURL
}()
lazy var managedObjectModel: NSManagedObjectModel = {
// The managed object model for the application. This property is not optional. It is a fatal error for the application not to be able to find and load its model.
let modelURL = NSBundle.mainBundle().URLForResource("SavedVariables", withExtension: "momd")!
return NSManagedObjectModel(contentsOfURL: modelURL)!
}()
lazy var persistentStoreCoordinator: NSPersistentStoreCoordinator? = {
// The persistent store coordinator for the application. This implementation creates and return a coordinator, having added the store for the application to it. This property is optional since there are legitimate error conditions that could cause the creation of the store to fail.
// Create the coordinator and store
var coordinator: NSPersistentStoreCoordinator? = NSPersistentStoreCoordinator(managedObjectModel: self.managedObjectModel)
let url = self.applicationDocumentsDirectory.URLByAppendingPathComponent("webview_test.sqlite")
var error: NSError? = nil
var failureReason = "There was an error creating or loading the application's saved data."
if coordinator!.addPersistentStoreWithType(NSSQLiteStoreType, configuration: nil, URL: url, options: nil, error: &error) == nil {
coordinator = nil
// Report any error we got.
var dict = [String: AnyObject]()
dict[NSLocalizedDescriptionKey] = "Failed to initialize the application's saved data"
dict[NSLocalizedFailureReasonErrorKey] = failureReason
dict[NSUnderlyingErrorKey] = error
error = NSError(domain: "YOUR_ERROR_DOMAIN", code: 9999, userInfo: dict)
// Replace this with code to handle the error appropriately.
// abort() causes the application to generate a crash log and terminate. You should not use this function in a shipping application, although it may be useful during development.
NSLog("Unresolved error \(error), \(error!.userInfo)")
abort()
}
return coordinator
}()
lazy var managedObjectContext: NSManagedObjectContext? = {
// Returns the managed object context for the application (which is already bound to the persistent store coordinator for the application.) This property is optional since there are legitimate error conditions that could cause the creation of the context to fail.
let coordinator = self.persistentStoreCoordinator
if coordinator == nil {
return nil
}
var managedObjectContext = NSManagedObjectContext()
managedObjectContext.persistentStoreCoordinator = coordinator
return managedObjectContext
}()
// MARK: - Core Data Saving support
func saveContext () {
if let moc = self.managedObjectContext {
var error: NSError? = nil
if moc.hasChanges && !moc.save(&error) {
// Replace this implementation with code to handle the error appropriately.
// abort() causes the application to generate a crash log and terminate. You should not use this function in a shipping application, although it may be useful during development.
NSLog("Unresolved error \(error), \(error!.userInfo)")
abort()
}
}
}
func applicationWillTerminate(application: UIApplication) {
// Called when the application is about to terminate. Save data if appropriate. See also applicationDidEnterBackground:.
// Saves changes in the application's managed object context before the application terminates.
self.saveContext()
}
}
作为旁注......如果有人可以告诉我如何强制程序等待用户按下警告上的OK按钮，然后继续我将永远欠你的债务。
答案 0 :(得分：1)
我误解了核心数据的概念。相反，我现在遍历每个结果而不是
var res = results[0] as Codes
带
for res in results as [NSManagedObject] {
....
}
并获得我需要的结果，然后使用它们进行比较，这是一个粗制滥造的工作，但它确实有效。