Question

我正在通过在线视频课程学习iOS。我不确定为什么我会收到此错误。我觉得我一步一步地遵循了一切，我最终得到了这个错误：

通常我会查看错误和回溯以尝试查找错误发生的位置，但我是iOS的新手，我不理解输出。

2015-01-30 17:57:40.511 99RedBalloons[18322:1563170] *** Terminating app due to uncaught exception 'NSUnknownKeyException', reason: '[<_9RedBalloons.ViewController 0x7fb5d3e17750> setValue:forUndefinedKey:]: this class is not key value coding-compliant for the key backgroundimageView.'
*** First throw call stack:
(
    0   CoreFoundation                      0x000000010ca3ff35 __exceptionPreprocess + 165
    1   libobjc.A.dylib                     0x000000010e583bb7 objc_exception_throw + 45
    2   CoreFoundation                      0x000000010ca3fb79 -[NSException raise] + 9
    3   Foundation                          0x000000010ce577b3 -[NSObject(NSKeyValueCoding) setValue:forKey:] + 259
    4   CoreFoundation                      0x000000010c989e80 -[NSArray makeObjectsPerformSelector:] + 224
    5   UIKit                               0x000000010d590c7d -[UINib instantiateWithOwner:options:] + 1506
    6   UIKit                               0x000000010d3eff98 -[UIViewController _loadViewFromNibNamed:bundle:] + 242
    7   UIKit                               0x000000010d3f0588 -[UIViewController loadView] + 109
    8   UIKit                               0x000000010d3f07f9 -[UIViewController loadViewIfRequired] + 75
    9   UIKit                               0x000000010d3f0c8e -[UIViewController view] + 27
    10  UIKit                               0x000000010d30fca9 -[UIWindow addRootViewControllerViewIfPossible] + 58
    11  UIKit                               0x000000010d310041 -[UIWindow _setHidden:forced:] + 247
    12  UIKit                               0x000000010d31c72c -[UIWindow makeKeyAndVisible] + 42
    13  UIKit                               0x000000010d2c7061 -[UIApplication _callInitializationDelegatesForMainScene:transitionContext:] + 2628
    14  UIKit                               0x000000010d2c9d2c -[UIApplication _runWithMainScene:transitionContext:completion:] + 1350
    15  UIKit                               0x000000010d2c8bf2 -[UIApplication workspaceDidEndTransaction:] + 179
    16  FrontBoardServices                  0x00000001101102a3 __31-[FBSSerialQueue performAsync:]_block_invoke + 16
    17  CoreFoundation                      0x000000010c97553c __CFRUNLOOP_IS_CALLING_OUT_TO_A_BLOCK__ + 12
    18  CoreFoundation                      0x000000010c96b285 __CFRunLoopDoBlocks + 341
    19  CoreFoundation                      0x000000010c96aa43 __CFRunLoopRun + 851
    20  CoreFoundation                      0x000000010c96a486 CFRunLoopRunSpecific + 470
    21  UIKit                               0x000000010d2c8669 -[UIApplication _run] + 413
    22  UIKit                               0x000000010d2cb420 UIApplicationMain + 1282
    23  99RedBalloons                       0x000000010c4aacce top_level_code + 78
    24  99RedBalloons                       0x000000010c4aad0a main + 42
    25  libdyld.dylib                       0x000000010ed5d145 start + 1
    26  ???                                 0x0000000000000001 0x0 + 1
)
libc++abi.dylib: terminating with uncaught exception of type NSException
(lldb)

我不了解Traceback一位

代码：

import UIKit

class ViewController: UIViewController {
    @IBOutlet weak var balloonsLabel: UILabel!
    @IBOutlet weak var backgroundImageView: UIImageView!
    var balloons:[Balloon] = [];

    var currentIndex = 0;

    override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view, typically from a nib.
        self.createBalloons()
    }

    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
        // Dispose of any resources that can be recreated.
    }
    @IBAction func nextBalloonBarButtonItemPressed(sender: UIBarButtonItem) {
        let balloon = balloons[currentIndex]
        balloonsLabel.text = "\(balloon.number) balloon"
        backgroundImageView.image = balloon.image
        currentIndex += 1
    }

    func createBalloons() {
        for var balloonCount = 0; balloonCount <= 99; ++balloonCount {
            var balloon = Balloon();
            balloon.number = balloonCount;

            let randomNumber = Int(arc4random_uniform(UInt32(4)));

            switch randomNumber {
            case 1:
                balloon.image = UIImage(named: "RedBalloon1.jpg")
            case 2:
                balloon.image = UIImage(named: "RedBalloon2.jpg")
            case 3:
                balloon.image = UIImage(named: "RedBalloon3.jpg")
            default:
                balloon.image = UIImage(named: "RedBalloon4.jpg")
            }

            self.balloons.append(balloon);
        }
    }
}

Balloon.swft：

import Foundation
import UIKit

struct Balloon {
    var number = 0;
    var image = UIImage(named: "");

}

Answer 1

错误是说它不知道属性，backgroundimageView - 注意小写“i”。您的属性名称是带有大写“I”的backgroundImageView。在storyboard或xib中的某个位置，您正在使用此属性拼写错误。

未捕获的异常'NSUnknownKeyException'，类不符合键值编码

1 个答案: