有没有办法在Swift 3 Xcode 8中首先完成异步任务?

在您的完成区块中,当您完成构建 name 和 bio reloadData 从主队列:

DispatchQueue.main.async { 
    self.tableView.reloadData() 
}

我还提出了一些其他建议:

• NSURLConnection 密码它正在执行冗余请求,而您没有对响应执行任何操作;另外,它是一个弃用的API,应该删除;

• 你应该使用 URL NSURL ;

• 你应该使用 URLRequest NSMutableURLRequest ;

• String 而不是 NSString ;

• 你应该使用Swift Array 和 Dictionary 而不是 NSArray 和 NSDictionary

• 您的签名 didSelectRowAt 不正确。使用 IndexPath 不 NSIndexPath

• 您正在更新 名称 生物 来自 URLSession 后台队列。这不是线程安全的。您可以通过从主队列中更新这些来解决这个问题,以避免需要进行额外的同步。

• Poem . 这使代码更加简单。它也开辟了新的可能性(例如,如果您想对 大堆您将如何更新单独的 生物

struct Poem {
    let name: String
    let bio: String

    init?(dictionary: [String: Any]) {
        guard let name = dictionary["fullName"] as? String,
            let bio = dictionary["Bio"] as? String else {
                print("Did not find fullName/Bio")
                return nil
        }

        self.name = name
        self.bio = bio
    }
}

class TimelineViewController: UIViewController {

    @IBOutlet weak var contentTableView: UITableView!

    var poems = [Poem]()

    @IBOutlet weak var oPostBtn: UIButton!

    override func viewDidLoad() {
        super.viewDidLoad()
        getPoems()
    }

    func getPoems() {
        let url = URL(string: "http://192.168.1.6/Test/feed1.php")!
        var request = URLRequest(url: url)

        request.httpMethod = "GET"

        let task = URLSession.shared.dataTask(with: request) { data, response, error in
            guard let data = data, error == nil else {
                print("Error = \(error?.localizedDescription ?? "Unknown error")")
                return
            }

            if let response = response {
                print("Response=\(response)")
            }

            if let responseString = String(data: data, encoding: .utf8) {
                print("Response data = \(responseString)")
            }

            // Converting response to Dictionary

            guard let json = try? JSONSerialization.jsonObject(with: data),
                let responseObject = json as? [String: Any],
                let returnPoems = responseObject["returnPoems"] as? [[String: Any]] else {
                    print("did not find returnPoems")
                    return
            }

            print(returnPoems)

            // dispatch the update of model and UI to the main queue

            DispatchQueue.main.async {
                self.poems = returnPoems.flatMap { Poem(dictionary: $0) }
                self.contentTableView.reloadData()
            }
        }

        task.resume()
    }

}

extension TimelineViewController: UITableViewDelegate, UITableViewDataSource {

    func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
        let cell = contentTableView.dequeueReusableCell(withIdentifier: "PoemCell", for: indexPath)

        let poem = poems[indexPath.row]

        cell.textLabel?.text = poem.name
        cell.detailTextLabel?.text = poem.bio

        return cell
    }

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

    func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
        print("You selected cell #\(indexPath.row)!")

        // let indexPath = tableView.indexPathForSelectedRow!                         // why do this? ... the indexPath was passed to this function
        // let currentCell = tableView.cellForRow(at: indexPath)! as UITableViewCell  // why do this? ... you don't care about the cell ... go back to you model

        let poem = poems[indexPath.row]

        // do something with poem, e.g.

        print(poem)
    }
}