我正在尝试改组此数组(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
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()
我迷失在如何改组INSPhotoViewable数组中。
更新:这是我的代码。它运行似乎没有错误,但没有拖尾:
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()])
}
}
}
}
您的扩展程序返回一个改组后的数组,它不会对现有的数组进行改组。
因此,您可以执行以下操作:
for photo in photos.shuffle() {
// work
}
如果您不需要将改组后的数组保留在变量中,或者
let shuffled = photos.shuffle()
for photo in shuffled {
// work
}
如果可以的话。
说明:extension CollectionType
在list.shuffleInPlace()
上一个工作拷贝数组-它然后返回洗牌后的副本。
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