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JiosDev
Asked:2020-02-25 23:00:47 +0000 UTC2020-02-25 23:00:47 +0000 UTC

随机选择一个文件进行读取

  • 772

我正在尝试将随机值（来自枚举的文件名）传递给文件读取方法的参数。但它会引发错误 OptinalValue:file 。

如何将结构中的随机文件名传递给 getDataFromFIle() 方法参数

读取文件.swift

import Foundation

var content:String!

class readFile
{
      //метод для читки файла
    func getDataFromFile(name: String , type:String)
    {

        let pathFile = Bundle.main.path(forResource: name, ofType: type)
        //в этом рядке ошибка
        let contentString = try! NSString(contentsOfFile: pathFile!, encoding: String.Encoding.utf8.rawValue)
        let  randomContent = contentString.components(separatedBy: [".","!"]).randomElement()!//.replacingOccurrences(of: "\"", with: "")
        content = randomContent
    }
}

任务文件.swift

import Foundation

struct TaskName
{
    enum LvlOne
    {
        case taskOneLvlOne
        case taskTwoLvlOne
        case taskThreeLvlOne

        var fileNameLvlOne:String
        {
            switch self {
            case .taskOneLvlOne:
                return "taskOneLvlOne"
            case .taskTwoLvlOne:
                return "taskTwoLvlOne"
            case.taskThreeLvlOne:
                return "TaskThreeLvlOne"
            }
        }
    }
    enum LvlTwo
    {
        case taskOneLvlTwo
        case taskTwoLvlTwo
        case taskThreeLvltwo

        var fileNameLvlTwo:String
        {
            switch self {
            case .taskOneLvlTwo:
                return "taskOneLvlTwo"
            case .taskTwoLvlTwo:
                return "taskTwoLvlTwo"
            case.taskThreeLvltwo:
                return "taskThreeLvltwo"
            }
        }
    }
}

ShowContent.swift

func getContent()
{
    let contentFile = readFile.init()
    conentFile.getDateFromFile(name: TaskName.LvlTwo.allCases.randomElement()!, type: "txt")
    let conentFile = content

    lebel.text = contentFile!
}
ios

1 个回答

  1. Best Answer

    在您的情况下，您可以这样做，例如，通过使用泛型创建方法

    /// Метод для выбора случайного значения, передаем в него первое значение в enum
/// https://stackoverflow.com/a/26261971/3004003
func randomEnumElement<T: RawRepresentable>(_ arg: T) -> T where T.RawValue==UInt32 {

    // find the maximum enum value
    var count: UInt32 = 0

    while let _ = T.init(rawValue: count) {
        count += 1
    }

    // pick and return a new value
    let rand = arc4random_uniform(count)

    return T.init(rawValue: rand)!
}

    然后enum使用它会是这样的

    struct TaskName
{
    enum LvlOne : UInt32
    {
        case taskOneLvlOne
        case taskTwoLvlOne
        case taskThreeLvlOne

        static var randomElement: Self {
            randomEnumElement(LvlOne.taskOneLvlOne)
        }

        static var fileNameLvlOne: String
        {
            switch randomElement {
            case .taskOneLvlOne:
                return "taskOneLvlOne"
            case .taskTwoLvlOne:
                return "taskTwoLvlOne"
            case.taskThreeLvlOne:
                return "TaskThreeLvlOne"
            }
        }

    }

    // ...
}

    用法

    let fileName = TaskName.LvlOne.fileNameLvlOne
getDataFromFile(name: fileName, type: "txt")
    • 1

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