Question

我是一名学生，对编码非常陌生（在这种情况下，使用Swift语言编写Xcode）。我试图使用按钮/滑块/手势来更改变量，如下所示：

有两个变量（firstVariable和secondVariable），并设置了一个UIslider输入，该输入应定义变量的值我希望变量与滑块/触摸手势的值相同，但即使在模拟器中滚动滑块后，变量仍保持4和6。我认为是因为它们超出了滑块功能的范围，但是如何链接它们？

class MyViewController : UIViewController {
    
    var firstVariable = 4
    
    override func viewDidLoad() {
        super.viewDidLoad()
        
        var secondVariable = 6
        print(secondVariable)
        print(firstVariable)
        let myslider = UISlider()

        //create a UISLider
        myslider.maximumValue = 100
        myslider.minimumValue = 0
        myslider.value = 30
        myslider.frame = CGRect(x: 150, y: 200, width: 200, height: 40)
        myslider.addTarget(self, action: #selector(sliderinput), for: UIControl.Event.valueChanged)
        self.view.addSubview(myslider)
    }
    
    @objc func sliderinput(sender: UISlider) {
        
        firstVariable = Int(sender.value)
        secondVariable = Int(sender.value)
    }
    
}

谢谢！

Answer 1

首先，将<section> <div class="wrapper"> <img id="main-slider" src="https://via.placeholder.com/1365x528?text=Slider"> <div class="badge"> <span class="text">Contact us</span> <a class="link">(555) <strong>123 4567</strong></a> </div> </div> </section>放在viewDidLoad之外，因为您无法在viewDidLoad之外访问它。要了解secondVariable，请阅读this。并且您需要打印变量的值才能看到值实际上在变化。

scope

Answer 2

对不起，这是真实情况。我想制作一个无限的时间轴，例如iOS日历天标签或视频编辑软件的时间轴。我还没有弄清楚如何从触摸的开始和结束获取距离，以及如何在开始时将其链接到scrollDistance变量，因此我可以创建向下滚动效果，然后创建一个pinchgesturerecognizer来设置间距/缩放线之间。我知道我可以使用UIscrollview或UIcollectionview，但是我觉得创建自定义一个xD是个好主意再次感谢大家的支持！：D

import UIKit

class ViewController: UIViewController {
    
    let lineElements: Array = [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
    let spacing: Int = 30  //spacing between elements
    var scrollDistance = 90  // 90 for example, this should be the pangesture distance
    
    //UIPanGestureRecogn function to determine the Y scroll distance from touch began to ended
    @objc func touchinput (sender: UIPanGestureRecognizer) {
        let touchlocation = sender.location(in: view)
        var touchStart: CGPoint
        var touchEnd: CGPoint
        print("touch current location is", touchlocation)
        
        if sender.state == UIGestureRecognizer.State.began {
            touchStart = sender.location(in: view)
            print("touch start", touchStart)
        } else if sender.state == UIGestureRecognizer.State.ended {
            touchEnd = sender.location(in: view)
            print("touch end", touchEnd)
        }
        //I haven’t figure out how to get the distance between start and end and link it to the scrollDistance
        //let scrollDistance = touchEnd.y - touchStart.y
    }
    
    override func viewDidLoad() {
        super.viewDidLoad()
        // ===================== Timeline a partir daqui =========================
        let totalElements: Int = lineElements.count
        
        for n in 1...totalElements {
            
            let yPosition = lineElements[n - 1] * spacing + scrollDistance //Get Line heigh index times the spacing + scroll distance by touch pan gesture
            let hourlabel = UILabel()
            let linepath = UIBezierPath()
            
            linepath.move(to: CGPoint(x: 60, y: yPosition))
            linepath.addLine(to: CGPoint(x: 350, y: yPosition))
            linepath.lineWidth = 8
            let lineshape = CAShapeLayer()
            lineshape.path = linepath.cgPath
            lineshape.strokeColor = UIColor.blue.cgColor
            lineshape.fillColor = UIColor.white.cgColor
            self.view.layer.addSublayer(lineshape)
            
            hourlabel.frame = CGRect(x: 5, y: yPosition - 20, width: 45, height: 40)
            hourlabel.text = "\(n):00"
            hourlabel.font = UIFont(name: "Avenir-Claro", size: 12)
            hourlabel.textColor = UIColor.blue
            hourlabel.textAlignment = .right
            self.view.addSubview(hourlabel)
        }
        
        // ===== GESTURE =====
        let gesto = UIPanGestureRecognizer()
        gesto.addTarget(self, action: #selector(touchinput))
        view.addGestureRecognizer(gesto)
    }
    
}
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如何使用按钮/滑块/触摸动作更改变量值？

2 个答案: