Swift - UIStepper

一、

import UIKit
class ViewController: UIViewController{
    
    var stepper:UIStepper!
    var label:UILabel!
    
    override func viewDidLoad() {
        super.viewDidLoad()
        stepper = UIStepper()
        stepper.center = self.view.center
        //設置stepper的初始值
        stepper.maximumValue = 10
        stepper.minimumValue = 1;
        stepper.value = 5.5
        //設置每次增減的值
        stepper.stepValue = 0.5
        //設置stepper能夠按住不放來連續更改值
        stepper.isContinuous=true
        //設置stepper是否循環（最大值時再增長數值從最小值開始）
        stepper.wraps = true
        stepper.addTarget(self, action: #selector(stepperValueIschanged), for: .valueChanged)
        self.view.addSubview(stepper)
        label = UILabel(frame: CGRect(x: 100, y: 190, width: 300, height: 30))
        label.text = "當前值爲\(stepper.value)"
        self.view.addSubview(label)
        
    }
   
    @objc func stepperValueIschanged(){
    
        label.text = "當前值爲：\(stepper.value)"
    }
}

 微調器（UIStepper）控件包含兩個按鈕「+」和「-」