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?


当前回答

因为这个答案还没有在这里,只是想指出,你也可以使用infoDictionary属性来获取信息plist作为字典,Bundle.main.infoDictionary。

比如bundle。main。如果您只对info plist中的特定项感兴趣,则可以使用kCFBundleNameKey作为String)。

// Swift 4

// Getting info plist as a dictionary
let dictionary = Bundle.main.infoDictionary

// Getting the app display name from the info plist
Bundle.main.infoDictionary?[kCFBundleNameKey as String]

// Getting the app display name from the info plist (another way)
Bundle.main.object(forInfoDictionaryKey: kCFBundleNameKey as String)

其他回答

如果我想将.plist转换为Swift字典,这是我所做的:

if let path = NSBundle.mainBundle().pathForResource("Config", ofType: "plist") {
  if let dict = NSDictionary(contentsOfFile: path) as? Dictionary<String, AnyObject> {
    // use swift dictionary as normal
  }
}

为Swift 2.0编辑:

if let path = NSBundle.mainBundle().pathForResource("Config", ofType: "plist"), dict = NSDictionary(contentsOfFile: path) as? [String: AnyObject] {
    // use swift dictionary as normal
}

为Swift 3.0编辑:

if let path = Bundle.main.path(forResource: "Config", ofType: "plist"), let dict = NSDictionary(contentsOfFile: path) as? [String: AnyObject] {
        // use swift dictionary as normal
}

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。

最好使用本机字典和数组,因为它们已经针对swift进行了优化。也就是说你可以使用NS。我认为这种情况证明了这一点。下面是你如何实现它:

var path = NSBundle.mainBundle().pathForResource("Config", ofType: "plist")
var dict = NSDictionary(contentsOfFile: path)

到目前为止(在我看来),这是访问plist最简单和最有效的方法,但在未来,我希望苹果将添加更多的功能(比如使用plist)到本地字典中。

Plist是一个简单的Swift枚举,用于处理属性列表。

// load an applications info.plist data

let info = Plist(NSBundle.mainBundle().infoDictionary)
let identifier = info["CFBundleIndentifier"].string!

更多的例子:

import Plist

// initialize using an NSDictionary
// and retrieve keyed values

let info = Plist(dict)
let name = info["name"].string ?? ""
let age = info["age"].int ?? 0


// initialize using an NSArray
// and retrieve indexed values

let info = Plist(array)
let itemAtIndex0 = info[0].value


// utility initiaizer to load a plist file at specified path
let info = Plist(path: "path_to_plist_file")

// we support index chaining - you can get to a dictionary from an array via
// a dictionary and so on
// don't worry, the following will not fail with errors in case
// the index path is invalid
if let complicatedAccessOfSomeStringValueOfInterest = info["dictKey"][10]["anotherKey"].string {
  // do something
}
else {
  // data cannot be indexed
}

// you can also re-use parts of a plist data structure

let info = Plist(...)
let firstSection = info["Sections"][0]["SectionData"]
let sectionKey = firstSection["key"].string!
let sectionSecret = firstSection["secret"].int!

Plist.swift

Plist本身非常简单,下面是它的清单,以防你直接引用。

//
//  Plist.swift
//


import Foundation


public enum Plist {

    case dictionary(NSDictionary)
    case Array(NSArray)
    case Value(Any)
    case none

    public init(_ dict: NSDictionary) {
        self = .dictionary(dict)
    }

    public init(_ array: NSArray) {
        self = .Array(array)
    }

    public init(_ value: Any?) {
        self = Plist.wrap(value)
    }

}


// MARK:- initialize from a path

extension Plist {

    public init(path: String) {
        if let dict = NSDictionary(contentsOfFile: path) {
            self = .dictionary(dict)
        }
        else if let array = NSArray(contentsOfFile: path) {
            self = .Array(array)
        }
        else {
            self = .none
        }
    }

}


// MARK:- private helpers

extension Plist {

    /// wraps a given object to a Plist
    fileprivate static func wrap(_ object: Any?) -> Plist {

        if let dict = object as? NSDictionary {
            return .dictionary(dict)
        }
        if let array = object as? NSArray {
            return .Array(array)
        }
        if let value = object {
            return .Value(value)
        }
        return .none
    }

    /// tries to cast to an optional T
    fileprivate func cast<T>() -> T? {
        switch self {
        case let .Value(value):
            return value as? T
        default:
            return nil
        }
    }
}

// MARK:- subscripting

extension Plist {

    /// index a dictionary
    public subscript(key: String) -> Plist {
        switch self {

        case let .dictionary(dict):
            let v = dict.object(forKey: key)
            return Plist.wrap(v)

        default:
            return .none
        }
    }

    /// index an array
    public subscript(index: Int) -> Plist {
        switch self {
        case let .Array(array):
            if index >= 0 && index < array.count {
                return Plist.wrap(array[index])
            }
            return .none

        default:
            return .none
        }
    }

}


// MARK:- Value extraction

extension Plist {

    public var string: String?       { return cast() }
    public var int: Int?             { return cast() }
    public var double: Double?       { return cast() }
    public var float: Float?         { return cast() }
    public var date: Date?         { return cast() }
    public var data: Data?         { return cast() }
    public var number: NSNumber?     { return cast() }
    public var bool: Bool?           { return cast() }


    // unwraps and returns the underlying value
    public var value: Any? {
        switch self {
        case let .Value(value):
            return value
        case let .dictionary(dict):
            return dict
        case let .Array(array):
            return array
        case .none:
            return nil
        }
    }

    // returns the underlying array
    public var array: NSArray? {
        switch self {
        case let .Array(array):
            return array
        default:
            return nil
        }
    }

    // returns the underlying dictionary
    public var dict: NSDictionary? {
        switch self {
        case let .dictionary(dict):
            return dict
        default:
            return nil
        }
    }

}


// MARK:- CustomStringConvertible

extension Plist : CustomStringConvertible {
    public var description:String {
        switch self {
        case let .Array(array): return "(array \(array))"
        case let .dictionary(dict): return "(dict \(dict))"
        case let .Value(value): return "(value \(value))"
        case .none: return "(none)"
        }
    }
}

斯威夫特5

如果你想获取某个键的特定值,那么我们可以使用下面的扩展,它使用Bundle上的infoDictionary属性。

可以使用Bundle.main.infoDictionary获取所有信息。在表单字典中plist值,因此我们可以直接使用Bundle上的object(forInfoDictionaryKey: key)方法查询

extension Bundle {
    static func infoPlistValue(forKey key: String) -> Any? {
        guard let value = Bundle.main.object(forInfoDictionaryKey: key) else {
           return nil
        }
        return value
    }
}

使用

guard let apiURL = Bundle.infoPlistValue(forKey: "API_URL_KEY") as? String else { return }