Question

我试图改组这个数组（我正在使用https://github.com/inspace-io/INSPhotoGallery扩展名）：

lazy var photos: [INSPhotoViewable] = {
        return [
            INSPhoto(imageURL: NSURL(string: "http://i.imgur.com/JXY2d4A.jpg"), thumbnailImageURL: NSURL(string: "http://i.imgur.com/JXY2d4A.jpg")),
            INSPhoto(imageURL: NSURL(string: "http://i.imgur.com/NC4bqLB.jpg"), thumbnailImageURL: NSURL(string: "http://i.imgur.com/NC4bqLB.jpg")),
]()

我知道你可以使用

来改组Int数组

extension CollectionType {
    /// Return a copy of `self` with its elements shuffled
    func shuffle() -> [Generator.Element] {
        var list = Array(self)
        list.shuffleInPlace()
        return list
    }
}

extension MutableCollectionType where Index == Int {
    /// Shuffle the elements of `self` in-place.
    mutating func shuffleInPlace() {
        // empty and single-element collections don't shuffle
        if count < 2 { return }

        for i in 0..<count - 1 {
            let j = Int(arc4random_uniform(UInt32(count - i))) + i
            guard i != j else { continue }
            swap(&self[i], &self[j])
        }
    }
}

[1, 2, 3].shuffle()

我迷失了如何改组INSPhotoViewable数组。

更新：这是我的代码。它似乎运行没有错误，但它没有改组：

extension CollectionType {

    /// Return a copy of `self` with its elements shuffled
    func shuffle() -> [Generator.Element] {
        var list = Array(self)
        list.shuffleInPlace()
        return list
    }
}

extension MutableCollectionType where Index == Int {
    /// Shuffle the elements of `self` in-place.
    mutating func shuffleInPlace() {
        // empty and single-element collections don't shuffle
        if count < 2 { return }

        for i in 0..<count - 1 {
            let j = Int(arc4random_uniform(UInt32(count - i))) + i
            guard i != j else { continue }
            swap(&self[i], &self[j])
        }
    }
}

class ViewController: UIViewController {


    @IBOutlet weak var collectionView: UICollectionView!
    var useCustomOverlay = false


    lazy var photos: [INSPhotoViewable] = {
        return [
            INSPhoto(imageURL: NSURL(string: "http://i.imgur.com/JXY2d4A.jpg"), thumbnailImageURL: NSURL(string: "http://i.imgur.com/JXY2d4A.jpg")),
            INSPhoto(imageURL: NSURL(string: "http://i.imgur.com/NC4bqLB.jpg"), thumbnailImageURL: NSURL(string: "http://i.imgur.com/NC4bqLB.jpg")),
            INSPhoto(imageURL: NSURL(string: "http://i.imgur.com/jBbQXNz.jpg"), thumbnailImageURL: NSURL(string: "http://i.imgur.com/jBbQXNz.jpg")),
            INSPhoto(imageURL: NSURL(string: "http://i.imgur.com/WCXkdwW.jpg"), thumbnailImageURL: NSURL(string: "http://i.imgur.com/WCXkdwW.jpg")),
            INSPhoto(imageURL: NSURL(string: "http://i.imgur.com/p7ujK0t.jpg"), thumbnailImageURL: NSURL(string: "http://i.imgur.com/p7ujK0t.jpg")),
            INSPhoto(imageURL: NSURL(string: "http://i.imgur.com/Ak4qwsS.jpg"), thumbnailImageURL: NSURL(string: "http://i.imgur.com/Ak4qwsS.jpg")),
            INSPhoto(imageURL: NSURL(string: "http://i.imgur.com/w2JJtDf.jpg"), thumbnailImageURL: NSURL(string: "http://i.imgur.com/w2JJtDf.jpg")),
            INSPhoto(imageURL: NSURL(string: "http://i.imgur.com/HCCSco3.jpg"), thumbnailImageURL: NSURL(string: "http://i.imgur.com/HCCSco3.jpg")),
            INSPhoto(imageURL: NSURL(string: "http://i.imgur.com/Za6Ialf.jpg"), thumbnailImageURL: NSURL(string: "http://i.imgur.com/Za6Ialf.jpg")),

            INSPhoto(imageURL: NSURL(string: "http://i.imgur.com/Pqc6k4v.jpg"), thumbnailImageURL: NSURL(string: "http://i.imgur.com/Pqc6k4v.jpg")),
            INSPhoto(imageURL: NSURL(string: "http://i.imgur.com/D8BBMd4.jpg"), thumbnailImageURL: NSURL(string: "http://i.imgur.com/D8BBMd4.jpg")),
            INSPhoto(imageURL: NSURL(string: "http://i.imgur.com/bggxrss.jpg"), thumbnailImageURL: NSURL(string: "http://i.imgur.com/bggxrss.jpg")),
            INSPhoto(imageURL: NSURL(string: "http://i.imgur.com/w1Lnl2c.jpg"), thumbnailImageURL: NSURL(string: "http://i.imgur.com/w1Lnl2c.jpg")),
            INSPhoto(imageURL: NSURL(string: "http://i.imgur.com/qoA0qA9.jpg"), thumbnailImageURL: NSURL(string: "http://i.imgur.com/qoA0qA9.jpg")),
            INSPhoto(imageURL: NSURL(string: "http://i.imgur.com/DkCEfkw.jpg"), thumbnailImageURL: NSURL(string: "http://i.imgur.com/DkCEfkw.jpg")),
            INSPhoto(imageURL: NSURL(string: "http://i.imgur.com/U4ihOo6.jpg"), thumbnailImageURL: NSURL(string: "http://i.imgur.com/U4ihOo6.jpg")),
            INSPhoto(imageURL: NSURL(string: "http://i.imgur.com/QvLBs7A.jpg"), thumbnailImageURL: NSURL(string: "http://i.imgur.com/QvLBs7A.jpg")),
            INSPhoto(imageURL: NSURL(string: "http://i.imgur.com/ZytdIk1.jpg"), thumbnailImageURL: NSURL(string: "http://i.imgur.com/ZytdIk1.jpg")),

        ]
    }()

    override func viewDidLoad() {
        super.viewDidLoad()
        collectionView.delegate = self
        collectionView.dataSource = self

        photos.shuffle()

        for photo in photos {
            if let photo = photo as? INSPhoto {
                photo.attributedTitle = NSAttributedString(string: "Note: Click top right to download wallpaper, \nscroll left or right to browse", attributes: [NSForegroundColorAttributeName: UIColor.whiteColor()])
            }
        }


    }


}

Answer 1

您的扩展程序返回一个随机数组，它不会将现有数据随机播放。

所以，你可以这样做：

for photo in photos.shuffle() {
    // work
}

如果您不需要将混洗数组保留在变量中，或者

let shuffled = photos.shuffle()

for photo in shuffled {
    // work
}

如果你这样做。

说明：在extension CollectionType中list.shuffleInPlace()对数组的副本进行操作 - 然后返回随机副本。

如何随机播放INSPhotoViewable（自定义）数组？

1 个答案: