此操作失败（无法扩展非标称类型“任何”）
extension Any {
func literal() -> String {
if let booleanValue = (self as? Bool) {
return String(format: (booleanValue ? "true" : "false"))
}
else
if let intValue = (self as? Int) {
return String(format: "%d", intValue)
}
else
if let floatValue = (self as? Float) {
return String(format: "%f", floatValue)
}
else
if let doubleValue = (self as? Double) {
return String(format: "%f", doubleValue)
}
else
{
return String(format: "<%@>", self)
}
}
}
就像我想在字典（自身）中使用它到xml字符串工厂一样
extension Dictionary {
// Return an XML string from the dictionary
func xmlString(withElement element: String, isFirstElement: Bool) -> String {
var xml = String.init()
if isFirstElement { xml.append("<?xml version=\"1.0\" encoding=\"utf-8\"?>\n") }
xml.append(String(format: "<%@>\n", element))
for node in self.keys {
let value = self[node]
if let array: Array<Any> = (value as? Array<Any>) {
xml.append(array.xmlString(withElement: node as! String, isFirstElemenet: false))
}
else
if let dict: Dictionary<AnyHashable,Any> = (value as? Dictionary<AnyHashable,Any>) {
xml.append(dict.xmlString(withElement: node as! String, isFirstElement: false))
}
else
{
xml.append(String(format: "<%@>", node as! CVarArg))
xml.append((value as Any).literal
xml.append(String(format: "</%@>\n", node as! CVarArg))
}
}
xml.append(String(format: "</%@>\n", element))
return xml.replacingOccurrences(of: "&", with: "&", options: .literal, range: nil)
}
}
我正在尝试以某种方式减少代码，因为上述代码段在我正在构建的原型中重复了几次，但这不是做到这一点的方式（带有代码段复制品的工作副本，但是很丑吗？）
基本上，我想为Any值生成一个文字-以前是从字典中获取的。
答案 0 :(得分：0)
好像你can't add extensions to Any。但是，您还有其他选择-将其设置为函数toLiteral(value: Any) -> String，或者可能更整洁的解决方案；使用description: String属性，该属性存在于符合CustomStringConvertible的所有类型上，包括String，Int，Bool和Float-您的代码将简化为xml.append(value.description)。然后，您只需对可能得到的任何其他类型进行简单的实现即可。
答案 1 :(得分：0)
好吧，终于成功了。首先是预备知识：每个对象都需要有一个dictionary（）方法来编组自己。注意：“ k。###”是结构静态常量-即k.name是“ name”，等等。我有两个对象，一个PlayItem和一个PlayList：
class PlayItem : NSObject {
var name : String = k.item
var link : URL = URL.init(string: "http://")!
var time : TimeInterval
var rank : Int
var rect : NSRect
var label: Bool
var hover: Bool
var alpha: Float
var trans: Int
var temp : String {
get {
return link.absoluteString
}
set (value) {
link = URL.init(string: value)!
}
}
func dictionary() -> Dictionary<String,Any> {
var dict = Dictionary<String,Any>()
dict[k.name] = name
dict[k.link] = link.absoluteString
dict[k.time] = time
dict[k.rank] = rank
dict[k.rect] = NSStringFromRect(rect)
dict[k.label] = label ? 1 : 0
dict[k.hover] = hover ? 1 : 0
dict[k.alpha] = alpha
dict[k.trans] = trans
return dict
}
}
class PlayList : NSObject {
var name : String = k.list
var list : Array <PlayItem> = Array()
func dictionary() -> Dictionary<String,Any> {
var dict = Dictionary<String,Any>()
var items: [Any] = Array()
for item in list {
items.append(item.dictionary())
}
dict[k.name] = name
dict[k.list] = items
return dict
}
}
注意的任何值，使元数据必须成为字典的合法类型；它有助于别名，因此在PlayItem中，“ temp”是链接网址的字符串版本，其getter / setter会翻译。
在需要时，例如执行writeRowsWith拖放式tableview处理程序，
func tableView(_ tableView: NSTableView, writeRowsWith rowIndexes: IndexSet, to pboard: NSPasteboard) -> Bool {
if tableView == playlistTableView {
let objects: [PlayList] = playlistArrayController.arrangedObjects as! [PlayList]
var items: [PlayList] = [PlayList]()
var promises = [String]()
for index in rowIndexes {
let item = objects[index]
let dict = item.dictionary()
let promise = dict.xmlString(withElement: item.className, isFirstElement: true)
promises.append(promise)
items.append(item)
}
let data = NSKeyedArchiver.archivedData(withRootObject: items)
pboard.setPropertyList(data, forType: PlayList.className())
pboard.setPropertyList(promises, forType:NSFilesPromisePboardType)
pboard.writeObjects(promises as [NSPasteboardWriting])
}
else
{
let objects: [PlayItem] = playitemArrayController.arrangedObjects as! [PlayItem]
var items: [PlayItem] = [PlayItem]()
var promises = [String]()
for index in rowIndexes {
let item = objects[index]
let dict = item.dictionary()
let promise = dict.xmlString(withElement: item.className, isFirstElement: true)
promises.append(promise)
items.append(item)
}
let data = NSKeyedArchiver.archivedData(withRootObject: items)
pboard.setPropertyList(data, forType: PlayList.className())
pboard.setPropertyList(promises, forType:NSFilesPromisePboardType)
pboard.writeObjects(promises as [NSPasteboardWriting])
}
return true
}
发生这种情况的原因是这些xmlString扩展和toLiteral函数-因为您无法扩展“任何”：
func toLiteral(_ value: Any) -> String {
if let booleanValue = (value as? Bool) {
return String(format: (booleanValue ? "1" : "0"))
}
else
if let intValue = (value as? Int) {
return String(format: "%d", intValue)
}
else
if let floatValue = (value as? Float) {
return String(format: "%f", floatValue)
}
else
if let doubleValue = (value as? Double) {
return String(format: "%f", doubleValue)
}
else
if let stringValue = (value as? String) {
return stringValue
}
else
if let dictValue: Dictionary<AnyHashable,Any> = (value as? Dictionary<AnyHashable,Any>)
{
return dictValue.xmlString(withElement: "Dictionary", isFirstElement: false)
}
else
{
return ((value as AnyObject).description)
}
}
extension Array {
func xmlString(withElement element: String, isFirstElemenet: Bool) -> String {
var xml = String.init()
xml.append(String(format: "<%@>\n", element))
self.forEach { (value) in
if let array: Array<Any> = (value as? Array<Any>) {
xml.append(array.xmlString(withElement: "Array", isFirstElemenet: false))
}
else
if let dict: Dictionary<AnyHashable,Any> = (value as? Dictionary<AnyHashable,Any>) {
xml.append(dict.xmlString(withElement: "Dictionary", isFirstElement: false))
}
else
{
xml.append(toLiteral(value))
}
}
xml.append(String(format: "<%@>\n", element))
return xml
}
}
extension Dictionary {
// Return an XML string from the dictionary
func xmlString(withElement element: String, isFirstElement: Bool) -> String {
var xml = String.init()
if isFirstElement { xml.append("<?xml version=\"1.0\" encoding=\"utf-8\"?>\n") }
xml.append(String(format: "<%@>\n", element))
for node in self.keys {
let value = self[node]
if let array: Array<Any> = (value as? Array<Any>) {
xml.append(array.xmlString(withElement: node as! String, isFirstElemenet: false))
}
else
if let dict: Dictionary<AnyHashable,Any> = (value as? Dictionary<AnyHashable,Any>) {
xml.append(dict.xmlString(withElement: node as! String, isFirstElement: false))
}
else
{
xml.append(String(format: "<%@>", node as! CVarArg))
xml.append(toLiteral(value as Any))
xml.append(String(format: "</%@>\n", node as! CVarArg))
}
}
xml.append(String(format: "</%@>\n", element))
return xml
}
func xmlHTMLString(withElement element: String, isFirstElement: Bool) -> String {
let xml = self.xmlString(withElement: element, isFirstElement: isFirstElement)
return xml.replacingOccurrences(of: "&", with: "&", options: .literal, range: nil)
}
}
这将继续另一个解决方案，即上面的toLiteral（）建议，希望对其他人有所帮助。
享受。