使用多个 Alamofire 链接请求填充 tableview

Question

我是 Alamofire 的新手，我正在关注 IOS Apps with REST APIs 这本书，我尝试解析 JSON 并填充 tableview，但问题是它在函数 loadGists 完成调用 Alamofire 链接请求之前调用 numberOfRowsInSection，所以我可以填充数组，然后相应地填充表格视图，似乎 .responseArray 函数被称为异步或在 numberOfRowsInSection 函数之后调用。

var gists: [Gist]!

@IBOutlet var tabelView1: UITableView!
override func viewDidLoad() {
    super.viewDidLoad()



self.tabelView1.delegate = self
        self.tabelView1.dataSource = self
}

override func viewDidAppear(animated: Bool) {
    super.viewDidAppear(animated)
    loadGists()
    }


func loadGists() {
GitHubAPIManager.sharedInstance.getPublicGists() { result in
guard result.error == nil else {
print(result.error)
// TODO: display error
return
}
if let fetchedGists = result.value {
self.gists = fetchedGists
}
DispatchQueue.main.async  {
    self.tableView1.reloadData()
    }

}
    }

GitHubAPIManager 类所在的位置：

class GitHubAPIManager: NSObject {


static let sharedInstance = GitHubAPIManager()

func getPublicGists(completionHandler: (Result<[Gist]>) -> Void) {
Alamofire.request(GistRouter.GetPublic())
.responseArray { (response) in
completionHandler(response.result)
}
}
} 

而responseArray是：

public func responseArray<T: ResponseJSONObjectSerializable>(
completionHandler: Response<[T]) -> Self {
let serializer = ResponseSerializer<[T]> { request, response, data, error in
guard error == nil else {
return .Failure(error!)
}
guard let responseData = data else {
let failureReason = "Array could not be serialized because input data was nil."
let error = Error.errorWithCode(.DataSerializationFailed,
failureReason: failureReason)
return .Failure(error)
}
let JSONResponseSerializer = Request.JSONResponseSerializer(options: .AllowFragments)
let result = JSONResponseSerializer.serializeResponse(request, response,
responseData, error)
switch result {
case .Success(let value):
let json = SwiftyJSON.JSON(value)
var objects: [T] = []
for (_, item) in json {
if let object = T(json: item) {
objects.append(object)
}
}
return .Success(objects)
case .Failure(let error):
return .Failure(error)
}
}
return response(responseSerializer: serializer, completionHandler: completionHandler)
}

对于表格视图：

    func tableView(tableView: UITableView,
numberOfRowsInSection section: Int) -> Int {
return gists.count
}

func tableView(tableView: UITableView, cellForRowAtIndexPath
indexPath: NSIndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCellWithIdentifier("Cell", forIndexPath: indexPath)
let gist = gists[indexPath.row]
cell.textLabel!.text = gist.description
cell.detailTextLabel!.text = gist.ownerLogin

return cell
}

GistRouter 是：

enum GistRouter: URLRequestConvertible {

    static let baseURLString:String = "https://api.github.com"

    case getPublic() 




        var method: HTTPMethod {

            switch self {

            case .getPublic:
                return .get
            }
        }

        func asURLRequest() throws -> URLRequest {

        let result: (path: String, parameters: [String: AnyObject]?) = {

            switch self {
            case .getPublic:
                return ("/gists/public", nil)
            }
        }()


        let URL = Foundation.URL(string: GistRouter.baseURLString)!




            var UrlRequest: URLRequest? = URLRequest(url: URL.appendingPathComponent(result.path))

            UrlRequest = try URLEncoding.default.encode(UrlRequest!, with: result.parameters)


        UrlRequest?.httpMethod = method.rawValue

        return UrlRequest!
    }

而 Gist 类是：

class Gist: ResponseJSONObjectSerializable  {


    var id: String?
    var description: String?
    var ownerLogin: String?
    var ownerAvatarURL: String?
    var url: String?


    required init(json: SwiftyJSON.JSON) {
        self.description = json["description"].string
        self.id = json["id"].string
        self.ownerLogin = json["owner"]["login"].string
        self.ownerAvatarURL = json["owner"]["avatar_url"].string
        self.url = json["url"].string
    }
    required init() {
    }

}

我已经尝试过 DispatchQueue.global(qos: .utility).async 以及 let semaphore = DispatchSemaphore(value: 0) 以不同的方式没有运气，我需要先完成所有 Alamofire 链式请求，然后调用 numberOfRowsInSection，请帮助。

Answer 1

它对我有用：

var gists = [Gist]() {
        didSet {

            self.tabelView1.reloadData()

        }
    }