我无法从 plist 键值中解包一个值

Question

我是 swift 的新手，我正在尝试将属性从 nsDictionary 加载到 vTitle

var nsDictionary: NSDictionary?
         if let path = Bundle.main.path(forResource: "AppData", ofType: "plist") {
            nsDictionary = NSDictionary(contentsOfFile: path)
         }
let vTitle:String = nsDictionary["LbVacationsTitle"]

当我调试时，我在 nsDictionary 中看到了正确的键，但我无法解开一个键的值 LbVacationsTitle 的类型是字符串

Answer 1

取决于您的风格偏好...

var nsDictionary: NSDictionary?
if let path = Bundle.main.path(forResource: "AppData", ofType: "plist") {
    nsDictionary = NSDictionary(contentsOfFile: path)
}
if let dict = nsDictionary {
    let vTitle = dict["LbVacationsTitle"] as? String
    if let vt = vTitle {
        // ...
    }
}

...或者...

var nsDictionary: NSDictionary?
if let path = Bundle.main.path(forResource: "AppData", ofType: "plist") {
    nsDictionary = NSDictionary(contentsOfFile: path)
}
guard let dict = nsDictionary else {
    print("Couldn't get a valid dictionary")
    return
}
let vTitle = dict["LbVacationsTitle"] as? String
guard let vt = vTitle else {
    print("Couldn't find a string matching LbVacationsTitle")
    return
}
// ...

Answer 2

请不要使用 Swift 中的 NSDictionary API 来读取属性列表。

有PropertyListSerialization（甚至PropertyListDecoder）

let url = Bundle.main.url(forResource: "AppData", withExtension: "plist")!
let data = try! Data(contentsOf: url)
let dictionary = try! PropertyListSerialization.propertyList(from: data, format: nil) as! [String:Any]
let vTitle = dictionary["LbVacationsTitle"] as! String

由于文件在应用程序包中是不可变的，任何崩溃都会揭示设计错误

我无法从 plist 键值中解包一个值

I can't Unwrap a value from a plist key value

nsdictionary

swift