Swift 表达式类型UIImage不明确，没有更多上下文

下面的代码生成此问题标题中显示的错误：for（index，image）in（backgroundImages）{

有人能建议如何消除这个错误吗

init!(backgroundImages:[UIImage], size:CGSize, scrollingDirection:ScrollingDirection, startingSpeed:CGFloat, speedDecreaseFactor:CGFloat) {
    self.backgrounds = []
    self.clonedBackgrounds = []
    self.speeds = []
    self.numberOfBackgrounds = (backgroundImages.count)
    self.scrollingDirection = scrollingDirection
    super.init(texture: nil, color:UIColor.clear, size: size)

    let zPos = 1.0 / CGFloat(numberOfBackgrounds)
    var currentSpeed = startingSpeed
    self.position = CGPoint(x:self.size.width/2, y:self.size.height/2)
    self.zPosition = -100

    for (index, image) in (backgroundImages) {
        let background = SKSpriteNode(texture: SKTexture(CGImage: image.CGImage), size:size)

        background.zPosition = self.zPosition - (zPos + (zPos * CGFloat(index)))
        background.position = CGPoint(x:0,y:0)
        let clonedBackground = background.copy() as! SKSpriteNode
        var clonedBackgroundX = background.position.x
        var clonedBackgroundY = background.position.y

        switch (scrollingDirection) {
        case .Right:
            clonedBackgroundX = -background.size.width
        case .Left:
            clonedBackgroundX = background.size.width
        default:
            break
        }

---

您可能是指backgroundImages.enumerated（）中（索引、图像）的

---

编译器无法理解如何将

backgroundImages

的元素解构为

（索引，图像）

您可能是指backgroundImages.enumerated（）中（索引，图像）的

编译器无法理解如何将
背景图像的元素解构为
（索引，图像）