如何在 swift 3 的 UITableView 中制作变量和使用

Question

我在这些全局变量中成功附加了 "title" 、 "url" 和 Video 但是当我试图在 numberOfRowsInSection 中使用时（ return titleName.count ）所以我得到 nil 或在 (cellForRowAt indexPath: ) 中作为 cell.videoTitle.text = titleName[indexPath.row] 所以我得到 nil..

Globalvariables is ...
var titleName:[String] = []
var videoID:[String] = []
var valueKey:[String] = []

然后在 viewDidLoad()

  override func viewDidLoad() {
        super.viewDidLoad()
        tableView.delegate = self
        tableView.dataSource = self

let urlRequest = URL(string: urlString)
URLSession.shared.dataTask(with: urlRequest! , completionHandler:{(data, response, error) -> Void in

    if (error != nil ){
        print(error.debugDescription)
    } else { 

        do{
    if let jsonObject = try?JSONSerialization.jsonObject(with: data!, options: .allowFragments) as? [String : AnyObject] {
        if let itemsArray = jsonObject?["items"] as? [[String:AnyObject]]{
            for snippetArray in itemsArray{
                if var snippet = snippetArray["snippet"] as? [String : AnyObject]{
                    if let titleItems = snippet["title"] as? String{
                        self.titleName.append(titleItems)

                    }
                    if let thumbnail = snippet["thumbnails"] as? [String : AnyObject]{
                        if let highValue = thumbnail["high"] as? [String : AnyObject]{
                            if let urlValueKey = highValue ["url"] as? String{
                                self.valueKey.append(urlValueKey)
                        }
                      }
                    }
                    if let resource = snippet["resourceId"] as? [String : AnyObject]{
                        if let videoId = resource["videoId"] as? String{
                            self.videoID.append(videoId)
                        }
                    }
                }


            }
            }

        }

        } catch let error as NSError {
            print(error)
        }
    }
}).resume()

tableView.reloadData()

}

这里是 JSOn.....

{
 "kind": "youtube#playlistItemListResponse",
 "etag": "\"Y3xTLFF3RLtHXX85JBgzzgp2Enw/ep-DtNxjJwMQbpCO1Lk3_ggMScU\"",
 "nextPageToken": "CAUQAA",
 "pageInfo": {
  "totalResults": 1636,
  "resultsPerPage": 5
 },
 "items": [
  {

   "kind": "youtube#playlistItem",
   "etag": "\"Y3xTLFF3RLtHXX85JBgzzgp2Enw/SYrDBZ2Ywgpf3zgCreEdB4PIf1o\"",
   "id": "UUZwDRPIG5DD2lxeCjap51NdbKiDO_M62c",
   "snippet": {
    "publishedAt": "2015-06-25T01:50:54.000Z",
    "channelId": "UCK8sQmJBp8GCxrOtXWBpyEA",
    "title": "The Google app: Summer",
    "description": "\"OK Google, when is Summer over?\"\n\nTalk to Google to get answers, find stuff nearby, and get things done. The Google app. Available on iOS and Android. \n\nDownload the app here: http://www.google.com/search/about/download/",
    "thumbnails": {
     "default": {
      "url": "https://i.ytimg.com/vi/BVGKskYZrw8/default.jpg",
      "width": 120,
      "height": 90
     },
     "medium": {
      "url": "https://i.ytimg.com/vi/BVGKskYZrw8/mqdefault.jpg",
      "width": 320,
      "height": 180
     },
     "high": {
      "url": "https://i.ytimg.com/vi/BVGKskYZrw8/hqdefault.jpg",
      "width": 480,
      "height": 360
     },
     "standard": {
      "url": "https://i.ytimg.com/vi/BVGKskYZrw8/sddefault.jpg",
      "width": 640,
      "height": 480
     },
     "maxres": {
      "url": "https://i.ytimg.com/vi/BVGKskYZrw8/maxresdefault.jpg",
      "width": 1280,
      "height": 720
     }
    },
    "channelTitle": "Google",
    "playlistId": "UUK8sQmJBp8GCxrOtXWBpyEA",
    "position": 0,
    "resourceId": {
     "kind": "youtube#video",
     "videoId": "BVGKskYZrw8"
    }
   }
  },
  ... MORE ITEMS ...
 ]
}

Answer 1

您上面的代码片段缺少将 JSON 检索到 data 的部分，该部分后来被 viewDidLoad() 中的 JSONSerialization 使用。

作为完整片段的示例，请查看此线程中的问题：How to get json to populate UITableView in Swift 3?

Answer 2

dataTask(with 异步工作。将 tableView.reloadData() 移动到 闭包末尾的完成块中。

两个注意事项：

Swift 3 中的 JSON 字典是 [String:Any].
不鼓励您使用多个数组作为数据源。使用自定义结构或 class.

如何在 swift 3 的 UITableView 中制作变量和使用

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