在开发中,我们有时需要生成一些随机的颜色。但 UIColor 没有提供方法或属性来直接获取随机颜色,这里对其进行扩展,方便使用。
1,扩展UIColor,增加随机颜色属性
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extension UIColor { //返回随机颜色
class var randomColor: UIColor { get { let red = CGFloat (arc4random()%256)/255.0 let green = CGFloat (arc4random()%256)/255.0 let blue = CGFloat (arc4random()%256)/255.0 return UIColor (red: red, green: green, blue: blue, alpha: 1.0) } } } |
2,使用样例
这里我们使用随机颜色来创建一个马赛克墙
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import UIKit class ViewController : UIViewController { override func viewDidLoad() { super .viewDidLoad() //马赛克宽度 let itemWidth = 5 //行数 let rowNums = Int ( self .view.bounds.height)/itemWidth //列数 let colNums = Int ( self .view.bounds.width)/itemWidth for i in 0...rowNums { for j in 0...colNums{ let item = UIView (frame: CGRect (x: j*itemWidth, y: i*itemWidth, itemWidth, height: itemWidth)) //使用随机颜色 item.backgroundColor = UIColor .randomColor self .view.addSubview(item) } } } override func didReceiveMemoryWarning() { super .didReceiveMemoryWarning() } } extension UIColor { //返回随机颜色
class var randomColor: UIColor { get { let red = CGFloat (arc4random()%256)/255.0 let green = CGFloat (arc4random()%256)/255.0 let blue = CGFloat (arc4random()%256)/255.0 return UIColor (red: red, green: green, blue: blue, alpha: 1.0) } } } |