xcode pathExtension 不可用：改为在 NSURL 上使用 pathExtension。斯威夫特 2.0
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pathExtension is unavailable: Use pathExtension on NSURL instead. Swift 2.0
提问by Alexander Khitev
I get mp3 files from Document Directory, I wrote that pathExtension equals "mp3", in the Swift 1.2 it is working, but in the Swift 2.0 I get the error " 'pathExtension' is unavailable: Use pathExtension on NSURL instead."
我从文档目录中获取 mp3 文件，我写道 pathExtension 等于“mp3”，在 Swift 1.2 中它正在工作，但在 Swift 2.0 中我收到错误“'pathExtension' 不可用：改为在 NSURL 上使用 pathExtension。”
func fetchFilesFromFolder() {
let fileManager = NSFileManager.defaultManager()
let folderPathURL = fileManager.URLsForDirectory(NSSearchPathDirectory.DocumentDirectory, inDomains: NSSearchPathDomainMask.UserDomainMask)[0]
if let directoryURLs = try? fileManager.contentsOfDirectoryAtURL(folderPathURL, includingPropertiesForKeys: nil, options: NSDirectoryEnumerationOptions.SkipsHiddenFiles) {
listOfMP3Files = directoryURLs.map(){ listOfMP3Files = directoryURLs.filter { extension String {
var ns: NSString {
return self as NSString
}
var pathExtension: String {
return ns.pathExtension
}
var lastPathComponent: String {
return ns.lastPathComponent
}
}
.pathExtension == "mp3" }.map { extension String {
var fileURL: URL {
return URL(fileURLWithPath: self)
}
var pathExtension: String {
return fileURL.pathExtension
}
var lastPathComponent: String {
return fileURL.lastPathComponent
}
}
.lastPathComponent! }
.lastPathComponent! }.filter(){ extension String {
var lastPathComponent: String {
get {
return (self as NSString).lastPathComponent
}
}
var pathExtension: String {
get {
return (self as NSString).pathExtension
}
}
var stringByDeletingLastPathComponent: String {
get {
return (self as NSString).stringByDeletingLastPathComponent
}
}
var stringByDeletingPathExtension: String {
get {
return (self as NSString).stringByDeletingPathExtension
}
}
var pathComponents: [String] {
get {
return (self as NSString).pathComponents
}
}
func stringByAppendingPathComponent(path: String) -> String {
let nsSt = self as NSString
return nsSt.stringByAppendingPathComponent(path)
}
func stringByAppendingPathExtension(ext: String) -> String? {
let nsSt = self as NSString
return nsSt.stringByAppendingPathExtension(ext)
}
}
.pathExtension == "mp3" } // error is here
}
}
采纳答案by vadian
Just change the order: first filter, than map. Now the method pathExtensionis applied to the NSURL objects.
只需更改顺序： first filter， than map。现在该方法pathExtension应用于 NSURL 对象。
extension String {
public var url: NSURL {
return NSURL(fileURLWithPath:self)
}
public var stringByDeletingLastPathComponent: String {
return String(url.URLByDeletingLastPathComponent)
}
}
You can omit the pair of parentheses after filterand mapusing the trailing closurerule.
您可以后省略对括号filter和map使用trailing closure规则。
Apple has removed the path related API from Stringto prefer the more suitable URL.
Apple 已经删除了与路径相关的 APIString以选择更合适的URL.
回答by Dharmesh Kheni
Or you can use this extension:
或者你可以使用这个扩展：
extension String {
var ns: NSString {
return self as NSString
}
var pathExtension: String {
return ns.pathExtension ?? ""
}
var lastPathComponent: String {
return ns.lastPathComponent ?? ""
}
}
回答by Leo Dabus
Xcode 8.3.2 ? Swift 3.1
Xcode 8.3.2 ? 斯威夫特 3.1
##代码##回答by hqt
回答by Matt Bearson
I combined Dharmesh and Leo's approaches to get my extension to work:
我结合了 Dharmesh 和 Leo 的方法来让我的扩展工作：
##代码##回答by Kevin
Swift Doc 1.2 specs regarding these funcs don't return an optional
To make it backward compatible to 1.2 in Swift 2.0, do this:
要使其向后兼容 Swift 2.0 中的 1.2，请执行以下操作：
Improve upon @Dharmesh Kheni 's version.
改进@Dharmesh Kheni 的版本。
##代码##