Swift 秒表应用程序崩溃，不知道我哪里出错了

Question

我正在尝试为我正在学习的编码制作一个秒表应用程序 class。在我运行代码之前我没有错误，但是一旦我运行它在 "build succeeds" 之后崩溃了。

import UIKit

class ViewController: UIViewController {

    override func viewDidLoad() {
        super.viewDidLoad()

    }

    var timer = NSTimer()

    var count = 0

    func updateTime() {

        count++

        timeLabel.text = "\(count)"

    }

    @IBOutlet weak var timeLabel: UILabel!

    @IBAction func playButton(sender: AnyObject) {

        timer = NSTimer.scheduledTimerWithTimeInterval(1, target: self, selector: Selector("updateTime"), userInfo: nil, repeats: true)

    }

    @IBAction func pauseButton(sender: AnyObject) {

    }

    @IBAction func resetButton(sender: AnyObject) {

    }



    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
        // Dispose of any resources that can be recreated.
    }


}

这是输出控制台：

2015-07-23 12:52:26.877 Stop Watch[7472:467329] *** Terminating app 
due to uncaught exception 'NSUnknownKeyException', reason:    
'[<Stop_Watch.ViewController   0x7ffdf1435b60> setValue:forUndefinedKey:]:
this class is not key value coding-compliant for the key play.'

*** First throw call stack:
(
  0   CoreFoundation       0x000000010a814c65 __exceptionPreprocess + 165
  1   libobjc.A.dylib      0x000000010c37fbb7 objc_exception_throw + 45
  2   CoreFoundation       0x000000010a8148a9 -[NSException raise] + 9
  3   Foundation           0x000000010ac32b53 -[NSObject(NSKeyValueCoding) setValue:forKey:] + 259
  4   CoreFoundation       0x000000010a75cd50 -[NSArray makeObjectsPerformSelector:] + 224
  5   UIKit                0x000000010b38b4eb -[UINib instantiateWithOwner:options:] + 1506
  6   UIKit                0x000000010b1e36d8 -[UIViewController _loadViewFromNibNamed:bundle:] + 242
  7   UIKit                0x000000010b1e3cc8 -[UIViewController loadView] + 109
  8   UIKit                0x000000010b1e3f39 -[UIViewController loadViewIfRequired] + 75
  9   UIKit                0x000000010b1e43ce -[UIViewController view] + 27
  10  UIKit                0x000000010b0ff289 -[UIWindow addRootViewControllerViewIfPossible] + 58
  11  UIKit                0x000000010b0ff64f -[UIWindow _setHidden:forced:] + 247
  12  UIKit                0x000000010b10bde1 -[UIWindow makeKeyAndVisible] + 42
  13  UIKit                0x000000010b0af417 -[UIApplication _callInitializationDelegatesForMainScene:transitionContext:] + 2732
  14  UIKit                0x000000010b0b219e -[UIApplication _runWithMainScene:transitionContext:completion:] + 1349
  15  UIKit                0x000000010b0b1095 -[UIApplication workspaceDidEndTransaction:] + 179
  16  FrontBoardServices   0x000000010de7c5e5 __31-[FBSSerialQueue performAsync:]_block_invoke_2 + 21
  17  CoreFoundation       0x000000010a74841c __CFRUNLOOP_IS_CALLING_OUT_TO_A_BLOCK__ + 12
  18  CoreFoundation       0x000000010a73e165 __CFRunLoopDoBlocks + 341
  19  CoreFoundation       0x000000010a73df25 __CFRunLoopRun + 2389
  20  CoreFoundation       0x000000010a73d366 CFRunLoopRunSpecific + 470
  21  UIKit                0x000000010b0b0b02 -[UIApplication _run] + 413
  22  UIKit                0x000000010b0b38c0 UIApplicationMain + 1282
  23  Stop Watch           0x000000010a618fa7 main + 135
  24  libdyld.dylib        0x000000010cab5145 start + 1
  25  ???                  0x0000000000000001 0x0 + 1
)
libc++abi.dylib: terminating with uncaught exception of type NSException
(lldb)

Answer 1

查看控制台日志后，我很确定崩溃是由于缺少插座连接引起的。

按 Cmd+Shift+F 并在搜索字段中键入 'play'。在故事板文件中查找 ...: Outlet = "play".

形式的条目

单击该条目并通过单击 play 旁边的 'x' 按钮将其删除。

这应该可以解决崩溃问题。

每当您看到以下形式的错误时： ... this class is not key value coding-compliant for the key ... 你应该检查你的故事板或 xib 中是否缺少插座。

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