swift - 将选择器添加到 UIStepper 的 addTarget 函数时出错 - Swift 3

Question

我正在尝试将 aUIStepper合并到 aUITextField中，同时增加步进器的值，并将其UITextField更新为该值。我不断收到错误：

“由于未捕获的异常''NSInvalidArgumentException'而终止应用程序，原因：'-[Calculator.SplitViewController stepperValueChanged：]：无法识别的选择器发送到实例 0x7fd730c0af30”`

每当我运行我的应用程序并点击步进器上的“+”按钮时。

有什么解决办法吗？我检查了我的选择器功能，我认为它看起来正确。

override func viewDidLoad() {
    super.viewDidLoad()

    partyOfStepper.autorepeat = true
    partyOfStepper.minimumValue = 1
    partyOfStepper.maximumValue = 99
    partyOfTextField.text = "\(Int(partyOfStepper.value))"
    partyOfStepper.addTarget(self, action: #selector(stepperValueChanged(stepper:)), for: .valueChanged)

}


@IBAction func calculateButtonTapped(_ sender: Any) {
}


func stepperValueChanged(stepper: UIStepper) {

    let stepperMapping: [UIStepper: UITextField] = [partyOfStepper: partyOfTextField]
    stepperMapping[stepper]!.text = "\(Int(stepper.value))"

}

Answer 1

正如 Nariv 所说，您的代码对我有用，请确保您之前没有在设计器中为 UIStepper 创建操作（检查连接检查器）：

import UIKit

class ViewController: UIViewController {

    @IBOutlet weak var partyOfStepper: UIStepper!
    @IBOutlet weak var partyOfTextField: UITextField!

    override func viewDidLoad() {
        super.viewDidLoad()

        partyOfStepper.autorepeat = true
        partyOfStepper.minimumValue = 1
        partyOfStepper.maximumValue = 99
        partyOfTextField.text = "\(Int(partyOfStepper.value))"
        partyOfStepper.addTarget(self, action: #selector(stepperValueChanged(stepper:)), for: .valueChanged)

    }

    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
    }

    func stepperValueChanged(stepper: UIStepper) {

        let stepperMapping: [UIStepper: UITextField] = [partyOfStepper: partyOfTextField]
        stepperMapping[stepper]!.text = "\(Int(stepper.value))"

    }

}