Xcode NSException和NSUnknownKeyException

Question

我刚接触MacOS和Xcode，我以前从未用过它们。

我必须使用Xcode为我的类制作一个简单的游戏。我已经成功地设置了一切(使用VirtualBox)，看了一些教程，并制作了一个简单的石头，布，剪刀游戏。

构建是成功的，但是当模拟器启动我的应用程序时，我得到一个关于我的三个按钮(Paper_Button)中的一个的错误。即使我在ViewController中注释按钮的代码，我仍然会得到错误。我在我的代码里查了一下，但是什么都没有...对于这个愚蠢的问题，我很抱歉，但我似乎没有找到任何解决方案。

这是错误：

Exception   NSException *   "[<RPS.ViewController 0x7fdf76008840> setValue:forUndefinedKey:]: this class is not key value coding-compliant for the key PAPER_Button."   0x0000600001ab83f0
name    __NSCFConstantString *  "NSUnknownKeyException" 0x00007fff801e80a0
reason  __NSCFString *  "[<RPS.ViewController 0x7fdf76008840> setValue:forUndefinedKey:]: this class is not key value coding-compliant for the key PAPER_Button."   0x00006000025e8280
userInfo    __NSDictionaryI *   2 key/value pairs   0x00006000001a10c0
reserved    __NSDictionaryM *   2 key/value pairs   0x00006000014c5fc0

    //
//  ViewController.swift
//  RPS
//
//  Created by MaiorCristian on 4/21/21.
//

import UIKit

//@interface
//SettingsViewController:
//UITableViewController

//BEFORE: UIViewController
//AFTER: UITableViewController

class ViewController: UIViewController {
    
    var player_points = 0
    var cpu_points = 0
    
    @IBOutlet weak var CPU_label: UILabel!
    @IBOutlet weak var YOU_label: UILabel!
    @IBOutlet weak var CPU_Image: UIImageView!
    @IBOutlet weak var WINNER: UILabel!
    
    
    var playersChoice = 0;
    @IBAction func ROCK_Button(_ sender: Any) {
        playersChoice = 1
        let cpuNumberChoice = Int.random(in: 1...3)
        setCPUimage(imageView: CPU_Image, imageNumber: cpuNumberChoice)
        
        //rock 1, paper 2, scissors 3
        
        //rock - rock
        if cpuNumberChoice == 1 && playersChoice == 1 {
            //tie
            WINNER.text = "WINNER: TIE!"
        }
        //paper - rock
        if cpuNumberChoice == 2 && playersChoice == 1 {
            cpu_points = cpu_points + 1
            WINNER.text = "WINNER: CPU!"        }
        //scissors - rock
        if cpuNumberChoice == 3 && playersChoice == 1 {
            player_points = player_points + 1
            WINNER.text = "WINNER: YOU!"        }
        
        YOU_label.text = "YOU: \(player_points)"
        CPU_label.text = "CPU: \(cpu_points)"
        
    }
    
    /*@IBAction func PAPER_Button(_ sender: Any) {
        playersChoice = 2
        let cpuNumberChoice = Int.random(in: 1...3)
        setCPUimage(imageView: CPU_Image, imageNumber: cpuNumberChoice)
        
        //rock 1, paper 2, scissors 3
        
        //paper - paper
        if cpuNumberChoice == 2 && playersChoice == 2 {
            WINNER.text = "WINNER: TIE!"        }
        //scissors - papper
        if cpuNumberChoice == 3 && playersChoice == 2 {
            cpu_points = cpu_points + 1
            WINNER.text = "WINNER: CPU!"        }
        //rock - papper
        if cpuNumberChoice == 1 && playersChoice == 2 {
            player_points = player_points + 1
            WINNER.text = "WINNER: YOU!"        }
        
        YOU_label.text = "YOU: \(player_points)"
        CPU_label.text = "CPU: \(cpu_points)"
        
    }
    */
    @IBAction func SCISSORS_Button(_ sender: Any) {
        playersChoice = 3
        let cpuNumberChoice = Int.random(in: 1...3)
        setCPUimage(imageView: CPU_Image, imageNumber: cpuNumberChoice)
        
        //rock 1, paper 2, scissors 3
        
        //scissors - scissors
        if cpuNumberChoice == 3 && playersChoice == 3 {
            WINNER.text = "WINNER: TIE!"        }
        //rock - scissors
        if cpuNumberChoice == 1 && playersChoice == 3 {
            cpu_points = cpu_points + 1
            WINNER.text = "WINNER: CPU!"        }
        //paper - scissors
        if cpuNumberChoice == 2 && playersChoice == 3 {
            player_points = player_points + 1
            WINNER.text = "WINNER: YOU!"        }
        
        YOU_label.text = "YOU: \(player_points)"
        CPU_label.text = "CPU: \(cpu_points)"
        
    }
    ///

        //
    override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view.
    }

    //@IBAction func

    func setCPUimage(imageView:UIImageView, imageNumber: Int){
        switch imageNumber {
        case 1://rock
            imageView.image = UIImage(named: "IMG_20210421_121204_edit_267680766477383")
        case 3://scissors
            imageView.image = UIImage(named: "IMG_20210421_121232_edit_267656474039366")
        case 2://paper
            imageView.image = UIImage(named: "IMG_20210421_121216_edit_267673424825822")
        
        default:
            print("error")
            //imageView.image = UIImage(named: "rock")
        }
        
    }
    
    
    
    
}

    libc++abi.dylib: terminating with uncaught exception of type NSException
*** Terminating app due to uncaught exception 'NSUnknownKeyException', reason: '[<RPS.ViewController 0x7fdf76008840> setValue:forUndefinedKey:]: this class is not key value coding-compliant for the key PAPER_Button.'
terminating with uncaught exception of type NSException
CoreSimulator 732.18.6 - Device: iPhone 11 (BCA23623-0F8A-46DA-BE7F-F3B81149500E) - Runtime: iOS 14.4 (18D46) - DeviceType: iPhone 11
*** Terminating app due to uncaught exception 'NSUnknownKeyException', reason: '[<RPS.ViewController 0x7fdf76008840> setValue:forUndefinedKey:]: this class is not key value coding-compliant for the key PAPER_Button.'
terminating with uncaught exception of type NSException
CoreSimulator 732.18.6 - Device: iPhone 11 (BCA23623-0F8A-46DA-BE7F-F3B81149500E) - Runtime: iOS 14.4 (18D46) - DeviceType: iPhone 11
(lldb) 

Answer 1

错误提示.xib或.storyboard文件引用的PAPER_Button在您的ViewController类中不存在。

我想从.xib或.storyboard文件中删除PAPER_Button可以修复这个错误。