ios - 随机选择一个UIImage

Question

我需要从这些点中选择一个。我将它们全部添加到 viewDidLoad 之前，我需要它来随机选择一个。我当前的代码返回错误 cannot assign to 'openingScreenDynamicDot in 'self'。这是如何解决的？

代码:

    let openingScreenDynamicDot = UIImage()
    let dotOne = UIImage(named: "dot1.png")
    let dotTwo = UIImage(named: "dot2.png")
    let dotThree = UIImage(named: "dot3.png")
    let dotFour = UIImage(named: "dot4.png")
    let dotFive = UIImage(named: "dot5.png")
    let dotSix = UIImage(named: "dot6.png")
    let dotSeven = UIImage(named: "dot7.png")
    let dotEight = UIImage(named: "dot8.png")
    let dotNine = UIImage(named: "dot9.png")
    let dotTen = UIImage(named: "dot10.png")
    let dotEleven = UIImage(named: "dot11.png")
    let dotTwelve = UIImage(named: "dot12.png")
    let dotThirteen = UIImage(named: "dot13.png")
    var imageNumber = arc4random()%13

override func viewDidLoad() {
        let theRandomImages = [dotOne, dotTwo, dotThree, dotFour, dotFive, dotSix, dotSeven, dotEight, dotNine, dotTen, dotEleven, dotTwelve, dotThirteen]
        openingScreenDynamicDot = theRandomImages.objectAtIndex(imageNumber)
}

Answer 1

您使用 let 关键字声明常量，使用 var 关键字声明变量。

所以把 let openingScreenDynamicDot 改成 var openingScreenDynamicDot

此外，swift 原生数组没有 objectAtIndex 方法，所以..

改变

openingScreenDynamicDot = theRandomImages.objectAtIndex(imageNumber)

到

openingScreenDynamicDot = theRandomImages[图像编号]