我在玩苹果的新Swift编程语言,遇到了一些问题…
目前我试图读取一个plist文件,在Objective-C中,我会做以下工作来获取内容作为NSDictionary:
NSString *filePath = [[NSBundle mainBundle] pathForResource:@"Config" ofType:@"plist"];
NSDictionary *dict = [[NSDictionary alloc] initWithContentsOfFile:filePath];
我如何得到一个plist作为一个字典在Swift?
我假设我可以得到路径到plist:
let path = NSBundle.mainBundle().pathForResource("Config", ofType: "plist")
当这工作(如果它是正确的?):我如何获得内容作为一个字典?
还有一个更普遍的问题:
是否可以使用默认的NS*类?我想是的……还是我遗漏了什么?据我所知,默认框架NS*类仍然有效,可以使用吗?
我已经创建了一个简单的字典初始化器替换NSDictionary(contentsOfFile: path)。只要去掉NS。
extension Dictionary where Key == String, Value == Any {
public init?(contentsOfFile path: String) {
let url = URL(fileURLWithPath: path)
self.init(contentsOfURL: url)
}
public init?(contentsOfURL url: URL) {
guard let data = try? Data(contentsOf: url),
let dictionary = (try? PropertyListSerialization.propertyList(from: data, options: [], format: nil) as? [String: Any]) ?? nil
else { return nil }
self = dictionary
}
}
你可以这样使用它:
let filePath = Bundle.main.path(forResource: "Preferences", ofType: "plist")!
let preferences = Dictionary(contentsOfFile: filePath)!
UserDefaults.standard.register(defaults: preferences)
你仍然可以在Swift中使用nsdictionary:
Swift 4
var nsDictionary: NSDictionary?
if let path = Bundle.main.path(forResource: "Config", ofType: "plist") {
nsDictionary = NSDictionary(contentsOfFile: path)
}
Swift 3+
if let path = Bundle.main.path(forResource: "Config", ofType: "plist"),
let myDict = NSDictionary(contentsOfFile: path){
// Use your myDict here
}
以及旧版本的Swift
var myDict: NSDictionary?
if let path = NSBundle.mainBundle().pathForResource("Config", ofType: "plist") {
myDict = NSDictionary(contentsOfFile: path)
}
if let dict = myDict {
// Use your dict here
}
NSClasses仍然可用,完全可以在Swift中使用。我想他们可能很快就会把重点转移到swift上,但是目前swift api并没有核心NSClasses的所有功能。
你可以使用它,我在github https://github.com/DaRkD0G/LoadExtension中创建了一个简单的字典扩展
extension Dictionary {
/**
Load a Plist file from the app bundle into a new dictionary
:param: File name
:return: Dictionary<String, AnyObject>?
*/
static func loadPlistFromProject(filename: String) -> Dictionary<String, AnyObject>? {
if let path = NSBundle.mainBundle().pathForResource("GameParam", ofType: "plist") {
return NSDictionary(contentsOfFile: path) as? Dictionary<String, AnyObject>
}
println("Could not find file: \(filename)")
return nil
}
}
你可以用它来计算负载
/**
Example function for load Files Plist
:param: Name File Plist
*/
func loadPlist(filename: String) -> ExampleClass? {
if let dictionary = Dictionary<String, AnyObject>.loadPlistFromProject(filename) {
let stringValue = (dictionary["name"] as NSString)
let intergerValue = (dictionary["score"] as NSString).integerValue
let doubleValue = (dictionary["transition"] as NSString).doubleValue
return ExampleClass(stringValue: stringValue, intergerValue: intergerValue, doubleValue: doubleValue)
}
return nil
}
以下是我找到的解决方案:
let levelBlocks = NSDictionary(contentsOfFile: NSBundle.mainBundle().pathForResource("LevelBlocks", ofType: "plist"))
let test: AnyObject = levelBlocks.objectForKey("Level1")
println(test) // Prints the value of test
我将测试类型设置为AnyObject,以关闭关于可能发生的意外推断的警告。
而且,它必须在类方法中完成。
访问并保存已知类型的特定值:
let value = levelBlocks.objectForKey("Level1").objectForKey("amount") as Int
println(toString(value)) // Converts value to String and prints it