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

我试图将

UIStepper

合并到

UITextField

中，当递增步进器的值时，

UITextField

会随之更新到该值。我不断得到错误：

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

每当我运行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，我认为它看起来是正确的

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))"

}

---

您的代码适合我，正如Nariv所说，请确保您以前没有在设计器中为UIStepper创建操作（签入Connections inspector）：

---

用完整准确的错误消息更新您的问题。您遗漏了消息的导入部分。您应该将按钮绑定到

calculateButtonTapped

，并通过

stepperValueChanged

更新步进器值。在界面生成器（故事板）中检查，您已经为该

UIStepper

设置了操作，只需删除该操作即可。

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))"

    }

}