Swift 5：如何读取plist文件中的变量？

Question

我搜索了一种方式（或模板）如何读取存储在plist文件中的变量。我看到了一些代码，但是最新的Swift版本中没有代码可用。

我是Swift的新手，实际上我没有确切检查它的工作方式。谁能这么好，举个例子？

我有一个CollectionView，想在我的plist文件中显示字符串。那是我的plist文件：

对于每个动物键（字典类型），两个子键（名称和图片）。根->动物->动物1

所有键所使用的“名称”和“图片”均为字典。现在，我想获取字典并在收藏视图中显示名称和图片。稍后我将添加更多的变量。我希望这是可以理解的：'D

我有不完整的代码：

override func viewDidLoad() {
    super.viewDidLoad()
    // Do any additional setup after loading the view.
    let path = Bundle.main.path(forResource: "Animals", ofType:"plist")!
    let dict = NSDictionary(contentsOfFile: path)
    SortData = dict!.object(forKey: "Animals") as! [Dictionary]
}

Answer 1

您可以像完成操作一样使用PropertyListSerialization或NSDictionary。在这里，您很可能是由于其他原因而出错。

class ViewController: UIViewController {

    var animals = [String: Any]()

    override func viewDidLoad() {
        super.viewDidLoad()

        fetchAnimals() // or fetchPropertyListAnimals()
        fetchPropertyListAnimals()
    }

    func fetchAnimals() {

        guard let path = Bundle.main.path(forResource: "Animals", ofType: "plist") else {
            print("Path not found")
            return
        }

        guard let dictionary = NSDictionary(contentsOfFile: path) else {
            print("Unable to get dictionary from path")
            return
        }

        if let animals = dictionary.object(forKey: "Animals") as? [String: Any] {
            self.animals = animals
        } else {
            print("Unable to find value for key named Animals")
        }
    }

    func fetchPropertyListAnimals() {
        var propertyListFormat =  PropertyListSerialization.PropertyListFormat.xml
        guard let path = Bundle.main.path(forResource: "Animals", ofType: "plist") else {
            print("Path not found")
            return
        }
        guard let data = FileManager.default.contents(atPath: path) else {
            print("Unable to get data from path")
            return
        }
        do {
            if let animals = try PropertyListSerialization.propertyList(from: data, options: .mutableContainersAndLeaves, format: &propertyListFormat) as? [String: Any] {
                self.animals = animals
            } else {
                print("Unable to find value for key named Animals")
            }

        } catch {
            print("Error reading plist: \(error), format: \(propertyListFormat)")
        }
    }
}

Answer 2

您的属性列表格式不是很方便。无论如何，如果需要数组，请使用键animals的数组创建属性列表（并将所有键命名为小写）

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
    <key>animals</key>
    <array>
        <dict>
            <key>name</key>
            <string>Tiger</string>
            <key>picture</key>
            <string>tiger_running</string>
        </dict>
        <dict>
            <key>name</key>
            <string>Jaguar</string>
            <key>picture</key>
            <string>jaguar_sleeping</string>
        </dict>
    </array>
</dict>
</plist>

然后创建两个结构

struct Root : Decodable {
    let animals : [Animal]
}

struct Animal : Decodable {
    let name, picture : String
}

和数据源数组

var animals = [Animal]()

并解码内容

override func viewDidLoad() {
    super.viewDidLoad()
    // Do any additional setup after loading the view.
    let url = Bundle.main.url(forResource: "Animals", withExtension:"plist")!
    do {
        let data = try Data(contentsOf: url)
        let result = try PropertyListDecoder().decode(Root.self, from: data)
        self.animals = result.animals
    } catch { print(error) }
}