UIStepper的使用

import UIKit

class ViewController: UIViewController {

    var label: UILabel?
    
    override func viewDidLoad() {
        super.viewDidLoad()
        
        self.setupStepper()
    }
    
    func setupStepper() {
    
        let stepper = UIStepper()
        stepper.center = self.view.center
        // 設(shè)置stepper的范圍與初始值
        stepper.maximumValue = 100
        stepper.minimumValue = 1
        stepper.value = 90
        // 設(shè)置每次增減的值
        stepper.stepValue = 10.0
        // 設(shè)置stepper可以按住不放來(lái)連續(xù)更改值
        stepper.isContinuous = true
        // 設(shè)置stepper是否循環(huán)（到最大值時(shí)再添加數(shù)值從最小值開始）
        stepper.wraps = true
        // 設(shè)置點(diǎn)擊事件
        stepper.addTarget(self, action: #selector(stepperChange(_:)), for: .valueChanged)

        // 加減符號(hào)圖標(biāo)，背景圖片，中間分割線圖片都可以替換成自己圖片
        let subImage = UIImage(named: "sub.png")
        let addImage = UIImage(named: "add.png")
        stepper.setDecrementImage(subImage, for: .normal)
        stepper.setIncrementImage(addImage, for: .normal)
        
        self.label = UILabel(frame: CGRect(x: 100, y: 100, width: 200, height: 40))
        self.label?.text = "當(dāng)前值為：\(stepper.value)"
        self.view.addSubview(self.label!)
        self.view.addSubview(stepper)
        
    }
    func stepperChange(_ stepper: UIStepper) {
        self.label?.text = "當(dāng)前值為：\(stepper.value)"
    }
}