Question

开发一款可以转换鞋码的应用。但是我在发布时遇到了这个错误。

EXC_BAD_INSTRUCTION（代码= EXC_1386_INOP，子代码= 0x0）

这是我的代码：

import UIKit

class ViewController: UIViewController {
    @IBOutlet weak var mensShoeSizeTextField: UITextField!

    @IBOutlet weak var mensConvertedShoeSizeLabel: UILabel!


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

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

    @IBAction func convertButtonPressed(sender: UIButton) {
       let sizeFromTextField = mensConvertedShoeSizeLabel.text
       let numberFromTextField = Int(sizeFromTextField!)
       var integerFromTextField = numberFromTextField!
       let conversionConstant = 30
       integerFromTextField += conversionConstant
       mensConvertedShoeSizeLabel.hidden = false
       let stringWithUpdatedShoeSize = "\(integerFromTextField)"
       mensConvertedShoeSizeLabel.text = stringWithUpdatedShoeSize
    }
}

Answer 1

两种错误都不同。
1.关于未找到的键盘，它是警告，因为您可能会将键盘隐藏在模拟器设置中。试试这个以冲洗警告

iOS Simulator -> Hardware -> Keyboard -> Toggle Software Keyboard

致命错误：在展开Optional值时意外发现nil 这是因为你的代码中的某个地方没有正确展开选项我可以从你的代码中看到的一件事是你没有打开这个：

让numberFromTextField = Int（sizeFromTextField！）

试试这样：

        let sizeFromTextField = mensConvertedShoeSizeLabel.text
        if let numberFromTextField = Int(sizeFromTextField!) {
            var integerFromTextField = numberFromTextField
            let conversionConstant = 30
            integerFromTextField += conversionConstant
            mensConvertedShoeSizeLabel.hidden = false
            let stringWithUpdatedShoeSize = "\(integerFromTextField)"
            mensConvertedShoeSizeLabel.text = stringWithUpdatedShoeSize

        }

Answer 2

如果错误为unexpectedly found nil while unwrapping an Optional value，则可能是由以下某行引起的：

let numberFromTextField = Int(sizeFromTextField!)
var integerFromTextField = numberFromTextField!

您可以在此处展开可选值，因此如果EXC_BAD_INSTRUCTION，您将获得nil。对于将String解析为Int，如果Int(string)返回nil，如果它无法将字符串解析为数字，那么这尤其成问题。

您应该更改代码以优雅地处理nil值：

import UIKit

class ViewController: UIViewController {
    @IBOutlet var mensShoeSizeTextField: UITextField?

    @IBOutlet var mensConvertedShoeSizeLabel: UILabel?

    @IBAction func convertButtonPressed(sender: UIButton) {
        if let sizeFromTextField = mensShoeSizeTextField?.text, let mensConvertedShoeSizeLabel = mensConvertedShoeSizeLabel, let integerFromTextField = Int(sizeFromTextField) {
            let conversionConstant = 30
            let convertedIntegerFromTextField = integerFromTextField + conversionConstant
            mensConvertedShoeSizeLabel.hidden = false
            let stringWithUpdatedShoeSize = "\(convertedIntegerFromTextField)"
            mensConvertedShoeSizeLabel.text = stringWithUpdatedShoeSize
        }
    }
}

Xcode Swift EXC_BAD_INSTRUCTION

2 个答案: