uipangeSturerognizer和随机颜色

Question

我有panperformed（）和RandomColors（）方法。当我将手指拖到屏幕上时，视图的颜色变化很快。

使用Pan手势时，如何使背景颜色更改慢3倍？

func randomColors() -> UIColor {

    let r = CGFloat(arc4random_uniform(255)) / 255.0
    let g = CGFloat(arc4random_uniform(255)) / 255.0
    let b = CGFloat(arc4random_uniform(255)) / 255.0

    return UIColor(red: r, green: g, blue: b, alpha: 1.0)
}

@IBAction func panPerformed(_ sender: UIPanGestureRecognizer) {

    if sender.state == .began || sender.state == .changed {

        let changeX = (self.view?.center.x)!
        let changeY = (self.view?.center.y)!
        
        sender.view?.center = CGPoint(x: changeX, y: changeY)
        sender.setTranslation(CGPoint.zero, in: self.view)
        
        self.view.backgroundColor = self.randomColors()
    }
}

我在语法（感谢@duncan c）方面添加了此代码：

     // Add some instance variables:
      var r: Int = 0
      var g: Int = 0
      var b: Int = 0

    override func viewDidLoad() {
    // Give your background view an initial color
    r = Int.random(in: 0...255)
    g = Int.random(in: 0...255)
    b = Int.random(in: 0...255)
    self.view.backgroundColor = currentColor()

    // Convert the r/g/b Int values to a UIColor
    func currentColor() -> UIColor {
    return UIColor(red: CGFloat(r)/255.0, green:  CGFloat(g)/255.0, blue: CGFloat(b)/255.0, alpha: 1.0)
}

    // Randomly change the input value by +/- 5
    func addOrSubtract(from: Int) -> Int {
    var result = from + Int.random(in: -5...5)

    // Don't let the new value go < 0 or > 255
    if result < 0 {
        result = 0
    } else if result > 255 {
        result = 255
    }
    return Int()
}

   // Adjust the r, g, and b values up or down a little.
    func randomizeColor() {
        r = addOrSubtract(from: r)
        g = addOrSubtract(from: g)
        b = addOrSubtract(from: b)
}

   @IBAction func panPerformed(_ sender: UIPanGestureRecognizer) {
    
        if sender.state == .began || sender.state == .changed {
            let changeX = (self.view?.center.x)!
            let changeY = (self.view?.center.y)!
        
            sender.view?.center = CGPoint (x: changeX, y: changeY)
            sender.setTranslation(CGPoint.zero, in: self.view)
            if changeX + changeY > 5 {
                randomizeColor()
               // self.view.backgroundColor =   self.randomColours() - the previous code
                self.view.backgroundColor = currentColor()
             }
         }
     }
 }

当我将手指拖到屏幕视图的颜色上时，将手指拖到黑色而不改变颜色时。什么原因？ addorSubtract（）？

Answer 1

您正在编制自己的功能。这实际上没有一种“正确的方式”，因为这是您的创建。

如果您不希望颜色突然变化，为什么不保存先前的颜色，并每隔几个拖动每几个颜色通道添加非常小的随机更改呢？类似的事情：（

// Add some instance variables:
var r: Int = 0
var g: Int = 0
var b: Int = 0

func viewDidLoad() {
  // Give your background view an initial color
  r = Int.random(0...255)
  g = Int.random(0...255)
  b = Int.random(0...255)
  self.view.backgroundColor = currentColor() 
}

// Convert the r/g/b Int values to a UIColor
func currentColor() -> UIColor {
    return UIColor(red: CGFloat(r)/255.0, green: CGFloat(g)/255.0, blue: CGFloat(b)/255.0, alpha: 1.0)
}

// Randomly change the input value by +/- 5
func addOrSubtract(from: Int) -> Int {
    var result = from + Int.random(-5...5)

    // Don't let the new value go < 0 or > 255
    if result < 0 {
        result = 0
    } else if result > 255 {
        result = 255
    }
}  

// Adjust the r, g, and b values up or down a little.
func randomizeColor() {
    r = addOrSubtract(from: r)
    g = addOrSubtract5(from: g)
    b = addOrSubtract5(from: b)
}

@IBAction func panPerformed(_ sender: UIPanGestureRecognizer) {

    if sender.state == .began || sender.state == .changed {
        let changeX = (self.view?.center.x)!
        let changeY = (self.view?.center.y)!
        
        sender.view?.center = CGPoint (x: changeX, y: changeY)
        sender.setTranslation(CGPoint.zero, in: self.view)

        // If the user move their finger by more than a few points, 
        // change the background color slightly
        if changeX + changeY > 5 {
            randomizeColor()
            self.view.backgroundColor = currentColor() 
        }
    }
}

将上述视为伪代码。它可能有一些语法错误，甚至可能是错误的。它并不是要复制/粘贴。）