Swift iOS : plist

plist

plist是一個XML的子集，使用UTF-8編碼的文本文件，它的根節點是一個字典，內容由多個主鍵和值構成。經常用來存儲App的配置信息。

能夠直接使用NSDictionary類直接存儲它的內容到plist內，好比這樣：

import UIKit
@UIApplicationMain
class AppDelegate: UIResponder, UIApplicationDelegate {
    var window : UIWindow?
    func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplicationLaunchOptionsKey: Any]?) -> Bool {
        window = UIWindow()
        window!.rootViewController = Page()
        window!.rootViewController!.view.backgroundColor = .blue
        window!.makeKeyAndVisible()
        return true
    }
}
class Page: UIViewController {
    let filename = "/profile.plist"
    let data:[String:String] = ["key1" : "value1", "key2":"value2", "key3":"value3"]
    override func viewDidLoad() {
        super.viewDidLoad()
        bar()
    }
    func bar(){
        do {
            let documentDirectory = NSSearchPathForDirectoriesInDomains(.documentDirectory, .userDomainMask, true)[0] as String
            let path = "\(documentDirectory)/\(filename)"
            print(path)
            let dict = NSDictionary(dictionary: data)
            let isWritten = dict.write(toFile: path, atomically: true)
            let dict1 = NSDictionary(contentsOfFile: path)
            print(dict1)
            print("file created: \(isWritten)")
            let text = try String(contentsOfFile: path, encoding: String.Encoding.utf8)
            print(text)
        }catch {print("\(error)")}

    }
}複製代碼

類NSDictionary的方法write能夠指定文件名，而後寫入到指定文件。初始化方法 NSDictionary(contentsOfFile:)能夠讀取plist到詞典對象內。

由於plist是UTF-8編碼的文本文件，因此，能夠使用String打開此文件，輸出內容以下（去掉主題無關的文件頭後）：

<plist version="1.0">
<dict> <key>key1</key> <string>value1</string> <key>key2</key> <string>value2</string> <key>key3</key> <string>value3</string> </dict>
</plist>複製代碼

做爲鍵值對的值，不單單但是是字符串，還能夠是數字、日期、數組和詞典。以下案例展現了plist存儲的更多可能性：

import UIKit
@UIApplicationMain
class AppDelegate: UIResponder, UIApplicationDelegate {
    var window : UIWindow?
    func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplicationLaunchOptionsKey: Any]?) -> Bool {
        window = UIWindow()
        window!.rootViewController = Page()
        window!.rootViewController!.view.backgroundColor = .blue
        window!.makeKeyAndVisible()
        return true
    }
}
class Page: UIViewController {
    let filename = "/profile.plist"
    let data:[String:Any] = ["key1" : "value1", "key2":["key11":"value11"], "key3":[1,"2",NSDate(),3.1]]
    override func viewDidLoad() {
        super.viewDidLoad()
        bar()
    }
    func bar(){
        do {
            let documentDirectory = NSSearchPathForDirectoriesInDomains(.documentDirectory, .userDomainMask, true)[0] as String
            let path = "\(documentDirectory)/\(filename)"
            print(path)
            let dict = NSDictionary(dictionary: data)
            let isWritten = dict.write(toFile: path, atomically: true)
            let dict1 = NSDictionary(contentsOfFile: path)
            print(dict1)
            print("file created: \(isWritten)")
            let text = try String(contentsOfFile: path, encoding: String.Encoding.utf8)
            print(text)
        }catch {print("\(error)")}
    }
}

7673複製代碼