如何使用步进器增加标签值？

Question

我有 priceLabel，其中有 Food 的属性 price。我想增加这个 priceLabel 是第一个值。例如 priceLabel 的第一个值是 15.00，当用户点击步进器时，第一个值随之增加是自己的值。（例如，轻按 2 次以增加 15 + 15 = 30）

我觉得像stepper.stepValue = priceLabel.text

这是我的代码

import UIKit
class DetailViewController: UIViewController {

@IBOutlet weak var foodTitle: UILabel!
@IBOutlet weak var foodSubTitle: UILabel!
@IBOutlet weak var foodPiece: UILabel!
@IBOutlet weak var foodPrice: UILabel!
@IBOutlet weak var drinkPicker: UITextField!
@IBOutlet weak var constantPieceLabel: UILabel!

var menuPieceStepper : UIStepper!
var drinkPickerView = UIPickerView()

var selectDrinkType: [String] = []
var detailFoodName : [String] = []
var detailFoodPrice : [Double] = [0.0]

var constPiece = 0

let foods = Food(name: ["Hamburger big mac",
                           "Patates",
                           "Whopper",
                           "Steakhouse"], price: [15.0, 20.0, 25.0, 30.0])

我需要使用 @IBAction 或 #selector ?

@IBAction func foodPieceStepper(_ sender: UIStepper) {
    foodPrice.text = Double(sender.value).description
}

@objc func foodPieceChangeStepper() {

    foodPrice.text = "\(menuPieceStepper.value)"
}

//TODO:- Add to basket
@IBAction func addBasket(_ sender: Any) {

        let destinationVC = MyCartViewController()

        destinationVC.fromDetailFoodNames = foods.name
        destinationVC.fromDetailFoodPrices = foods.price

    dismiss(animated: true)

}

override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
   if(segue.identifier == "addToCartSegue") {
        if let addToCartVC = segue.destination as? MyCartViewController {


            addToCartVC.fromDetailFoodNames = foods.name
            addToCartVC.fromDetailFoodPrices = foods.price

    }
   }
}

override func viewDidLoad() {
    super.viewDidLoad()

    menuPieceStepper = UIStepper()
    menuPieceStepper.value = 0.0
    menuPieceStepper.minimumValue = 0.0
    menuPieceStepper.maximumValue = 30.0
    menuPieceStepper.stepValue = foods.price.first!
    menuPieceStepper.addTarget(self, action: #selector(foodPieceChangeStepper), for: .valueChanged)

    foodPieceChangeStepper()

    drinkPickerView.delegate = self
    drinkPicker.inputView = drinkPickerView
    selectDrinkType = ["Ayran", "Kola", "Su", "Fanta", "Şalgam", "Sprite"]

    foodTitle.text = detailFoodName.description
    foodPrice.text = detailFoodPrice.description

    self.navigationController?.navigationItem.title = "Sipariş Detayı"

}

override func viewWillAppear(_ animated: Bool) {
    self.navigationController?.navigationBar.isHidden = false

}

override func viewWillDisappear(_ animated: Bool) {
    self.navigationController?.navigationBar.isHidden = true
}

}

Answer 1

使用选择器/IBAction 没有区别

@objc func foodPieceChangeStepper() { 
  let res = menuPieceStepper.value * foods.price.first!
  foodPrice.text = "\(res)"
}

那么你应该将步长值设置为

menuPieceStepper.stepValue = 1.0

并在步进动作中

menuPieceStepper.value * currentPiecePrice

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