class Sample<ItemType,AdaptorType> {
    var items = Array<ItemType>() 
    let adaptor = AdaptorType()   //Error: 'AdaptorType' is not constructible with '()'
}

我也尝试在init()中初始化它,但是同样的问题在于

class SampleGnericClass<ItemType,AdaptorType> {
    var items = Array<ItemType>() 
    let adaptor : AdaptorType
 
    init() {
        adaptor = AdaptorType()      //It doesn't work,same error occors here
    }
}

使用通用类型AdaptorType初始化适配器属性的正确方法是什么？万分感谢！

编辑：关于这个问题的完整代码

import UIKit
 
protocol XYManagedObject {
 
}
 
protocol XYNetworkProtocol {
 
    typealias ManagedObjectType : XYManagedObject
 
    func object(fromItemDictionary dictionary: NSDictionary?) -> ManagedObjectType?
    func objects(fromEntryDictionary dictionary: NSDictionary?) -> Array<ManagedObjectType>?
    func actionParameters(page: UInt?) -> (action: String,parameters: Dictionary<String,String>?)
    func pageSize() -> UInt? // nil for unlimited
}
 
class ProductAdaptor : XYNetworkProtocol {
 
    var filter = Dictionary<String,String>()
 
    typealias ManagedObjectType = XYProductObject
 
    func object(fromItemDictionary dictionary: NSDictionary?) -> ManagedObjectType? {
        //... Will return an object here
        return nil
    }
 
    func objects(fromEntryDictionary dictionary: NSDictionary?) -> Array<ManagedObjectType>? {
        //... will return an array of objects here
        return nil
    }
 
    func actionParameters(page: UInt?) -> (action: String,String>?) {
        var parameters = filter
        if page {
            parameters["page"] = "\(page!)"
        }
 
        return ("product_list",parameters)
    }
 
    func pageSize() -> UInt? {
        return 100
    }
}
 
class XYDataManager<ItemType: XYManagedObject,AdaptorType: XYNetworkProtocol> {
 
    var objects = Array<ItemType>()
    let adaptor = ProductAdaptor() //work around,adaptor should be any type conform to XYNetworkProtocol
 
    func loadPage(page: UInt?) -> (hasNextPage: Bool,items: Array<ItemType>?) {
        let fetcher = XYFetchController()
 
        let ap = adaptor.actionParameters(page)
        if let fetchedResult = fetcher.JSONObjectForAPI(ap.action,parameters: ap.parameters) {
 
            let npage = fetchedResult["npage"].integerValue
            var hasNextPage = true
            if !npage || !page {
                hasNextPage = false
            }
            else if npage <= page {
                hasNextPage = false
            }
 
            let objects = adaptor.objects(fromEntryDictionary: fetchedResult)
            return (hasNextPage,(objects as Array<ItemType>?))
        }
        else {
            return (false,nil)
        }
    }
}