每当我从TableViewController转到ViewController查看数据时，我都会收到一个终端错误。我很确定我实际上并没有以某种方式初始化数据，但由于我是xCode和Swift的新手，我不知道如何解决我的问题。
TableViewController（GasManifoldLogSheet）代码
import UIKit
import Foundation
import CoreData
class GasManifoldLogSheet: UIViewController, UITextFieldDelegate, NSFetchedResultsControllerDelegate, UITableViewDelegate {
// MARK: References
@IBOutlet weak var tableView: UITableView!
var items = [NSManagedObject]()
var currentIndexPath: NSIndexPath?
// MARK: Random Functions
func viewWillAppear() {
}
override func viewDidLoad() {
super.viewDidLoad()
title = "Gas Manifold Logs"
tableView.registerClass(UITableViewCell.self, forCellReuseIdentifier: "Cell")
fetchData()
}
// MARK: UITableView Data Source
func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
print("Message for NSManagedObject counting")
return items.count
}
func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCellWithIdentifier("Cell")! as UITableViewCell
let item = items[indexPath.row]
cell.textLabel?.text = item.valueForKey("date") as? String
print("Message for NSManagedObject -> Cell name")
return cell
}
func tableView(tableView: UITableView, didSelectRowAtIndexPath indexPath: NSIndexPath) {
currentIndexPath = indexPath
self.performSegueWithIdentifier("saveSegue", sender: nil)
}
// MARK: Functions
func fetchData() {
let appDelegate = UIApplication.sharedApplication().delegate as! AppDelegate
let managedObjectContext = appDelegate.managedObjectContext
let fetchRequest = NSFetchRequest(entityName: "GasManifoldLog")
do{
let fetchedResults = try managedObjectContext.executeFetchRequest(fetchRequest) as! [NSManagedObject]
items = fetchedResults
} catch {
print("error fetching results of search")
}
}
func initializeFetchedResultsController() {
let appDelegate = UIApplication.sharedApplication().delegate as! AppDelegate
let fetchRequest = NSFetchRequest(entityName: "GasManifoldLog")
let sortDescriptor = NSSortDescriptor(key: "date", ascending: true)
fetchRequest.sortDescriptors = [sortDescriptor]
let fetchedResultsController = NSFetchedResultsController(fetchRequest: fetchRequest, managedObjectContext: appDelegate.managedObjectContext, sectionNameKeyPath: "date", cacheName: nil)
fetchedResultsController.delegate = self
do {
try fetchedResultsController.performFetch()
} catch let error as NSError {
print(error)
}
}
override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject!) {
if segue.identifier == "saveSegue" {
let indexPath = self.tableView.indexPathForSelectedRow!
let theSelectedRow = [items[indexPath.row]]
let theDestination = segue.destinationViewController as! GasManifoldLogSheetEdit
print("All Variables have been set for sending data to the next view controller")
theDestination.carriedItems = theSelectedRow
print("Data was sent to the next view controller")
} else {
print("prepareForSegue function was called, but the segue identifier was not listed for a saved transition")
}
}
}
这里是ViewController（GasManifoldLogSheetEdit）代码（我现在只试图让一个标签实际显示文字）
import UIKit
import CoreData
class GasManifoldLogSheetEdit: UIViewController, UITextFieldDelegate, NSFetchedResultsControllerDelegate {
// MARK: References
@IBOutlet weak var displayInitials: UILabel!
@IBOutlet weak var displaySIN: UILabel!
@IBOutlet weak var displayRSP: UILabel!
@IBOutlet weak var displaySP: UILabel!
@IBOutlet weak var displayLSP: UILabel!
@IBOutlet weak var textfieldNotes: UITextField!
var carriedItems = [NSManagedObject]()
// MARK: Functions
override func viewDidLoad() {
displayInitials.text = valueForKey("initials") as? String
}
继承我的错误代码
[<EMGS.Users: 0x7fd6e3c264b0> (entity: Users; id: 0xd000000000040000 <x-coredata://91BF1700-C6BD-489A-9886-3BE9404ABE6F/Users/p1> ; data: <fault>), <EMGS.Users: 0x7fd6e3c2f3b0> (entity: Users; id: 0xd000000000080000 <x-coredata://91BF1700-C6BD-489A-9886-3BE9404ABE6F/Users/p2> ; data: <fault>)]
[<EMGS.Users: 0x7fd6e3c264b0> (entity: Users; id: 0xd000000000040000 <x-coredata://91BF1700-C6BD-489A-9886-3BE9404ABE6F/Users/p1> ; data: {
initials = AA;
loginStatus = 0;
password = A;
username = A;
}), <EMGS.Users: 0x7fd6e3c2f3b0> (entity: Users; id: 0xd000000000080000 <x-coredata://91BF1700-C6BD-489A-9886-3BE9404ABE6F/Users/p2> ; data: <fault>)]
Message for NSManagedObject counting
Message for NSManagedObject counting
Message for NSManagedObject counting
Message for NSManagedObject counting
Message for NSManagedObject -> Cell name
All Variables have been set for sending data to the next view controller
Data was sent to the next view controller
2016-10-18 14:03:44.245 EMGS[76584:1316311] *** Terminating app due to uncaught exception 'NSUnknownKeyException', reason: '[<EMGS.GasManifoldLogSheetEdit 0x7fd6e3de3ad0> valueForUndefinedKey:]: this class is not key value coding-compliant for the key initials.'
*** First throw call stack:
(
0 CoreFoundation 0x0000000101a53e65 __exceptionPreprocess + 165
1 libobjc.A.dylib 0x0000000103793deb objc_exception_throw + 48
2 CoreFoundation 0x0000000101a53aa9 -[NSException raise] + 9
3 Foundation 0x0000000101eaf888 -[NSObject(NSKeyValueCoding) valueForUndefinedKey:] + 226
4 EMGS 0x00000001014bcc63 _TFC4EMGS23GasManifoldLogSheetEdit11viewDidLoadfS0_FT_T_ + 211
5 EMGS 0x00000001014bcec2 _TToFC4EMGS23GasManifoldLogSheetEdit11viewDidLoadfS0_FT_T_ + 34
6 UIKit 0x0000000102406f98 -[UIViewController loadViewIfRequired] + 1198
7 UIKit 0x00000001024072e7 -[UIViewController view] + 27
8 UIKit 0x0000000102bb1f87 -[_UIFullscreenPresentationController _setPresentedViewController:] + 87
9 UIKit 0x00000001023d6f62 -[UIPresentationController initWithPresentedViewController:presentingViewController:] + 133
10 UIKit 0x0000000102419c8c -[UIViewController _presentViewController:withAnimationController:completion:] + 4002
11 UIKit 0x000000010241cf2c -[UIViewController _performCoordinatedPresentOrDismiss:animated:] + 489
12 UIKit 0x000000010241ca3b -[UIViewController presentViewController:animated:completion:] + 179
13 UIKit 0x00000001029933e0 __74-[UIStoryboardPresentationSegueTemplate newDefaultPerformHandlerForSegue:]_block_invoke + 133
14 UIKit 0x0000000102999f5c -[UIStoryboardSegueTemplate _performWithDestinationViewController:sender:] + 460
15 UIKit 0x0000000102999d5f -[UIStoryboardSegueTemplate _perform:] + 82
16 UIKit 0x0000000102409c0c -[UIViewController performSegueWithIdentifier:sender:] + 99
17 EMGS 0x00000001014aa336 _TFC4EMGS19GasManifoldLogSheet9tableViewfS0_FTCSo11UITableView23didSelectRowAtIndexPathCSo11NSIndexPath_T_ + 182
18 EMGS 0x00000001014aa3bf _TToFC4EMGS19GasManifoldLogSheet9tableViewfS0_FTCSo11UITableView23didSelectRowAtIndexPathCSo11NSIndexPath_T_ + 79
19 UIKit 0x00000001023b3d5e -[UITableView _selectRowAtIndexPath:animated:scrollPosition:notifyDelegate:] + 1887
20 UIKit 0x00000001023b3fb3 -[UITableView _userSelectRowAtPendingSelectionIndexPath:] + 388
21 UIKit 0x000000010227c4a2 _runAfterCACommitDeferredBlocks + 317
22 UIKit 0x000000010228fc01 _cleanUpAfterCAFlushAndRunDeferredBlocks + 95
23 UIKit 0x000000010229baf3 _afterCACommitHandler + 90
24 CoreFoundation 0x000000010197f367 __CFRUNLOOP_IS_CALLING_OUT_TO_AN_OBSERVER_CALLBACK_FUNCTION__ + 23
25 CoreFoundation 0x000000010197f2d7 __CFRunLoopDoObservers + 391
26 CoreFoundation 0x0000000101974f2b __CFRunLoopRun + 1147
27 CoreFoundation 0x0000000101974828 CFRunLoopRunSpecific + 488
28 GraphicsServices 0x0000000106090ad2 GSEventRunModal + 161
29 UIKit 0x0000000102270610 UIApplicationMain + 171
30 EMGS 0x00000001014bb20d main + 109
31 libdyld.dylib 0x00000001042a592d start + 1
)
libc++abi.dylib: terminating with uncaught exception of type NSException
(lldb)
编辑1 这是CoreData模型 http://imgur.com/a/zScvu
在我的应用程序中，我有一个TableView，显示Gas Manifold Sheets的所有条目（GasManifoldLogSheet）。从该TableView，您可以按创建按钮访问下一个ViewController并输入数据以在CoreData中创建实体。第二个用于数据输入的ViewController被调用（GasManifoldLogSheetNewRecord）。点击保存按钮后，您将被移回原始的TableView（GasManifoldLogSheet），在那里您将看到填充的实体列表或日志表。
当我在我的应用程序上选择单独的日志表时，它会执行一个名为（GasManifoldLogSheetEdit）的第三个ViewController的segue，您可以在其中查看/编辑数据。
每当我尝试使用键 initials （在viewDidLoad（）函数内）中的值来更改displayInitials的文本时，据我所知应该在变量/ NSManagedObject
编辑2 下面是第二个ViewController（GasManifoldLogSheetNewRecord）
的代码import UIKit
import CoreData
class GasManifoldLogSheetNewRecord: UIViewController {
// MARK: References
@IBOutlet weak var txtDate: UITextField!
@IBOutlet weak var txtSupplyPressure: UITextField!
@IBOutlet weak var txtLeftBankPressure: UITextField!
@IBOutlet weak var txtRightBankPressure: UITextField!
@IBOutlet weak var txtSideInUse: UITextField!
@IBOutlet weak var initials: UITextField!
@IBOutlet weak var txtDescription: UITextField!
// MARK: Loading Scripts
func viewWillAppear() {
}
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view.
// Automatic Date
let currentDate = NSDate()
let dateFormatter = NSDateFormatter()
dateFormatter.dateStyle = NSDateFormatterStyle.LongStyle
let convertedDate = dateFormatter.stringFromDate(currentDate)
txtDate.text = convertedDate
// Automatic Initials
let appDel:AppDelegate = (UIApplication.sharedApplication().delegate as! AppDelegate)
let context:NSManagedObjectContext = appDel.managedObjectContext
let request = NSFetchRequest(entityName: "Users")
request.returnsObjectsAsFaults = false
request.predicate = NSPredicate(format: "loginStatus = %@", "1")
let results:NSArray = try! context.executeFetchRequest(request)
if(results.count > 0) {
let res = results[0] as! NSManagedObject
initials.text = res.valueForKey("initials") as? String
} else {
print("Login Didn't Work")
}
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
// MARK: Opening and closing keyboard
func textFieldShouldReturn(textField: UITextField) -> Bool {
textField.resignFirstResponder()
return true
}
@IBAction func backgroundTap(sender: UITapGestureRecognizer) {
self.view .endEditing(true)
}
// MARK: Functions
@IBAction func btnCreate(sender: AnyObject) {
let appDel:AppDelegate = (UIApplication.sharedApplication().delegate as! AppDelegate)
let context:NSManagedObjectContext = appDel.managedObjectContext
let newGasManifoldLog = NSEntityDescription.insertNewObjectForEntityForName("GasManifoldLog", inManagedObjectContext: context) as NSManagedObject
if (txtDate.text!.isEmpty || initials.text!.isEmpty) {
let alertController = UIAlertController(title: "Error", message:
"Date and Initials are required.", preferredStyle: UIAlertControllerStyle.Alert)
alertController.addAction(UIAlertAction(title: "Dismiss", style: UIAlertActionStyle.Default,handler: nil))
self.presentViewController(alertController, animated: true, completion: nil)
return
}
newGasManifoldLog.setValue(txtDate.text, forKey: "date")
newGasManifoldLog.setValue(txtSupplyPressure.text, forKey: "supplyPressure")
newGasManifoldLog.setValue(txtLeftBankPressure.text, forKey: "leftBankPressure")
newGasManifoldLog.setValue(txtRightBankPressure.text, forKey: "rightBankPressure")
newGasManifoldLog.setValue(txtSideInUse.text, forKey: "sideInUse")
newGasManifoldLog.setValue(initials.text, forKey: "initials")
newGasManifoldLog.setValue(txtDescription.text, forKey: "jobDescription")
do {
try context.save()
print(newGasManifoldLog)
print("Object Saved")
} catch let error as NSError {
print(error)
}
}
/*
// MARK: - Navigation
// In a storyboard-based application, you will often want to do a little preparation before navigation
override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
// Get the new view controller using segue.destinationViewController.
// Pass the selected object to the new view controller.
}
*/
}
答案 0 :(得分：0)
阅读错误消息。关键部分是
[EMGS。 GasManifoldLogSheetEdit 0x7fd6e3de3ad0＆gt; valueForUndefinedKey ：]：此类与键缩写不符合键值编码。＆＃39;
然后在代码中查找valueForKey("initials")：
displayInitials.text = valueForKey("initials") as? String
由于没有明确的接收者，你实际上是打电话
displayInitials.text = <instance of GasManifoldLogSheetEdit>.valueForKey("initials") as? String
当然会崩溃。
您应该将carriedItems声明为单个对象
var carriedItem = NSManagedObject!
并传递prepareForSegue
let theSelectedRow = items[indexPath.row]
...
theDestination.carriedItem = theSelectedRow
现在你可以写
了displayInitials.text = carriedItem.valueForKey("initials") as? String
如评论中所述，我们建议您在super
viewDidLoad()
override func viewDidLoad() {
super.viewDidLoad
...
答案 1 :(得分：0)
我读到我必须向下转换NSManagedObject。这是我的解决方案
override func viewDidLoad() {
for items in carriedItems as [NSManagedObject] {
print(items)
displayInitials.text = items.valueForKey("initials") as? String
}
使用该代码，我现在可以使我的NSManagedObject中的值可读。