swift - 如何实例化给定类型的对象

Question

我想用给定类型实例化一个对象。这是对该函数的调用:

buildObjetFromType("data", typeClass: User.self)

函数代码如下:

public static func buildObjectFromType<T>(data: String, typeClass: T.Type) -> T{ 

    print(typeClass) // will print "User"
    var object:T?

    object as! T.Type // cast the object into an User -> NOT WORKING !

    // fill the object with the data, knowing 
    // return the object once it has been filled with the data.
}

这是我的用户类:

public class User {
    private var id:String?
    private var login:String?
    private var pwd:String?
    private var nom:String?
    private var prenom:String?

    public required init(){
        id = ""
        login = ""
        pwd = ""
        nom = ""
        prenom = ""
    }

    public convenience init(_login: String, _pwd: String){
        self.init()
        login = _login
        pwd = _pwd
    }

    public convenience init(_id: String, _login: String, _pwd: String, _nom: String, _prenom: String){
        self.init(_login: _login, _pwd: _pwd)
        id = _id
        nom = _nom
        prenom = _prenom
    }
}

Answer 1

参见:Instantiate an object of a generic type in Swift

假设您要实例化的所有类都有一个不带参数的必需初始值设定项(您可能希望它们从同一基类继承，并将此要求添加到您的函数中)，您可以执行以下操作:

static func instantiate<T where T: BaseClass>(data: String, cls: T.Type) -> T {
    let obj = T()
    // do something with obj and data
}