好的，所以我做了大量的搜索，我发现的所有内容似乎都与View Controllers有关，而且它们上的链接无法正常工作或没有连接。那不是我的问题。我有一个应用程序正在使用CoreData来密切关注表的列表，它们的表号，如果它们是否干净，以及它们是否正在使用中。但是，当我尝试使用setValue（）函数更改属性的键值时，它会崩溃我的应用程序，说明以下崩溃报告
2018-04-02 21:45:15.840265-0500 Trakr[26636:1455153] *** Terminating app due to uncaught exception 'NSUnknownKeyException', reason: '[<NSManagedObjectContext 0x6040001c4fb0> setValue:forUndefinedKey:]: this class is not key value coding-compliant for the key inUse.'
*** First throw call stack:
(
0 CoreFoundation 0x000000010d1af1e6 __exceptionPreprocess + 294
1 libobjc.A.dylib 0x0000000108f3d031 objc_exception_throw + 48
2 CoreFoundation 0x000000010d1af0b9 -[NSException raise] + 9
3 Foundation 0x000000010895eb47 -[NSObject(NSKeyValueCoding) setValue:forKey:] + 292
4 Trakr 0x0000000108615bee _T05Trakr24CheckTableViewControllerC18inUseSwitchChangedyypF + 846
5 Trakr 0x0000000108615e41 _T05Trakr24CheckTableViewControllerC18inUseSwitchChangedyypFTo + 81
6 UIKit 0x000000010ac1a448 -[UIApplication sendAction:to:from:forEvent:] + 83
7 UIKit 0x000000010ad95804 -[UIControl sendAction:to:forEvent:] + 67
8 UIKit 0x000000010ad95b21 -[UIControl _sendActionsForEvents:withEvent:] + 450
9 UIKit 0x000000010b8d6d60 -[UISwitchModernVisualElement sendStateChangeActions] + 73
10 UIKit 0x000000010b29889f -[UISwitchMVEGestureTrackingSession _sendStateChangeActionsIfNecessary] + 63
11 UIKit 0x000000010b8d74ec -[UISwitchModernVisualElement _handleLongPressWithGestureLocationInBounds:gestureState:] + 760
12 UIKit 0x000000010b21141b -[UIGestureRecognizerTarget _sendActionWithGestureRecognizer:] + 57
13 UIKit 0x000000010b21a1f0 _UIGestureRecognizerSendTargetActions + 109
14 UIKit 0x000000010b217a38 _UIGestureRecognizerSendActions + 307
15 UIKit 0x000000010b216c8c -[UIGestureRecognizer _updateGestureWithEvent:buttonEvent:] + 859
16 UIKit 0x000000010b1fbcf0 _UIGestureEnvironmentUpdate + 1329
17 UIKit 0x000000010b1fb773 -[UIGestureEnvironment _deliverEvent:toGestureRecognizers:usingBlock:] + 484
18 UIKit 0x000000010b1fa875 -[UIGestureEnvironment _updateGesturesForEvent:window:] + 281
19 UIKit 0x000000010ac9080b -[UIWindow sendEvent:] + 4064
20 UIKit 0x000000010ac34370 -[UIApplication sendEvent:] + 352
21 UIKit 0x000000010b57557f __dispatchPreprocessedEventFromEventQueue + 2796
22 UIKit 0x000000010b578194 __handleEventQueueInternal + 5949
23 CoreFoundation 0x000000010d151bb1 __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE0_PERFORM_FUNCTION__ + 17
24 CoreFoundation 0x000000010d1364af __CFRunLoopDoSources0 + 271
25 CoreFoundation 0x000000010d135a6f __CFRunLoopRun + 1263
26 CoreFoundation 0x000000010d13530b CFRunLoopRunSpecific + 635
27 GraphicsServices 0x000000010fa46a73 GSEventRunModal + 62
28 UIKit 0x000000010ac190b7 UIApplicationMain + 159
29 Trakr 0x000000010861e697 main + 55
30 libdyld.dylib 0x000000010e318955 start + 1
)
libc++abi.dylib: terminating with uncaught exception of type NSException
我不能为我的生活弄清楚为什么会这样。这是我的视图控制器类：
import UIKit
import CoreData
class CheckTableViewController: UIViewController, UIPickerViewDelegate, UIPickerViewDataSource {
@IBOutlet weak var backgroundImage: UIImageView!
@IBOutlet weak var pickerView: UIPickerView!
@IBOutlet weak var tableNumberLabel: UILabel!
@IBOutlet weak var cleanSwitch: UISwitch!
@IBOutlet weak var inUseSwitch: UISwitch!
var tablesList = [Table]()
override func viewDidLoad() {
super.viewDidLoad()
pickerView.delegate = self
pickerView.dataSource = self
let fetchRequest: NSFetchRequest<Table> = Table.fetchRequest()
do {
let tablesList = try PersistenceService.context.fetch(fetchRequest)
self.tablesList = tablesList
} catch {}
backgroundImage.addBlurEffect()
tableNumberLabel.text = "Select a Table"
cleanSwitch.isEnabled = false
inUseSwitch.isEnabled = false
if tablesList.isEmpty {
pickerView.isHidden = true
tableNumberLabel.text = "Add Some Tables"
} else {
pickerView.isHidden = false
}
// Do any additional setup after loading the view.
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
// MARK: - Picker View and Switch Controlls
func numberOfComponents(in pickerView: UIPickerView) -> Int {
return 1
}
func pickerView(_ pickerView: UIPickerView, numberOfRowsInComponent component: Int) -> Int {
return tablesList.count
}
func pickerView(_ pickerView: UIPickerView, titleForRow row: Int, forComponent component: Int) -> String? {
return String(tablesList[row].tableNumber)
}
func pickerView(_ pickerView: UIPickerView, didSelectRow row: Int, inComponent component: Int) {
if (tablesList.isEmpty) {
tableNumberLabel.text = "Add a table"
} else {
tableNumberLabel.text = String(tablesList[row].tableNumber)
if cleanSwitch.isEnabled == false {
cleanSwitch.isEnabled = true
}
if inUseSwitch.isEnabled == false {
inUseSwitch.isEnabled = true
}
if tablesList[row].isClean == true {
cleanSwitch.isOn = true
} else {
cleanSwitch.isOn = false
}
if tablesList[row].inUse == true{
inUseSwitch.isOn = true
} else {
inUseSwitch.isOn = false
}
}
}
@IBAction func cleanSwitchChanged(_ sender: Any) {
if cleanSwitch.isOn == false {
PersistenceService.context.setValue(false, forKey: "isClean")
} else {
PersistenceService.context.setValue(true, forKey: "isClean")
}
}
@IBAction func inUseSwitchChanged(_ sender: Any) {
if inUseSwitch.isOn == false {
let selectedRow = pickerView.selectedRow(inComponent: 0)
tablesList[selectedRow].inUse = false
PersistenceService.context.setValue(false, forKey: "inUse")
} else {
let selectedRow = pickerView.selectedRow(inComponent: 0)
tablesList[selectedRow].inUse = true
PersistenceService.context.setValue(true, forKey: "inUse")
}
}
}
这是我的PersistenceService类，负责CoreData功能的那个
import Foundation
import CoreData
class PersistenceService {
// MARK: - Core Data stack
private init() {}
static var context: NSManagedObjectContext {
return persistentContainer.viewContext
}
static var persistentContainer: NSPersistentContainer = {
/*
The persistent container for the application. This implementation
creates and returns a container, having loaded 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.
*/
let container = NSPersistentContainer(name: "tableModel")
container.loadPersistentStores(completionHandler: { (storeDescription, error) in
if let error = error as NSError? {
// Replace this implementation with code to handle the error appropriately.
// fatalError() 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.
/*
Typical reasons for an error here include:
* The parent directory does not exist, cannot be created, or disallows writing.
* The persistent store is not accessible, due to permissions or data protection when the device is locked.
* The device is out of space.
* The store could not be migrated to the current model version.
Check the error message to determine what the actual problem was.
*/
fatalError("Unresolved error \(error), \(error.userInfo)")
}
})
return container
}()
// MARK: - Core Data Saving support
static func saveContext () {
let context = persistentContainer.viewContext
if context.hasChanges {
do {
try context.save()
print("Saved to CoreData")
} catch {
// Replace this implementation with code to handle the error appropriately.
// fatalError() 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.
let nserror = error as NSError
fatalError("Unresolved error \(nserror), \(nserror.userInfo)")
}
}
}
}
最后，a screenshot of my tableModel CoreData Model
有人可以告诉我为什么这不起作用吗？我无法理解它的生命......
答案 0 :(得分：0)
您应该创建NSManagedObject的Table子类，而不是使用KVC。然后，您可以直接在“表”实例中设置值。
您还要将值设置为context.setValue(:)，您应首先创建Table的entityDescription，如下所示
var newTable = NSEntityDescription.insertNewObject(forEntityName: "Table", into: PersistenceService.context)
newTable.setValue(fale, forKey: "isClean")