how to make variable and use in UITableView in swift 3 - ios

Question

I am successfully appending "title" , "url" and Video in these Global Variables but when I am trying to use in numberOfRowsInSection as ( return titleName.count ) so I am getting nil or in (cellForRowAt indexPath: ) as cell.videoTitle.text = titleName[indexPath.row] so I am getting nil..
Globalvariables is ...
var titleName:[String] = []
var videoID:[String] = []
var valueKey:[String] = []
and then in 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()
}
and here is the 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

dataTask(with works asynchronously. Move tableView.reloadData() into the completion block at the end of the closure.
Two notes:
A JSON dictionary in Swift 3 is [String:Any].
You are discouraged from using multiple arrays as data source. Use a custom struct or class.

Answer 2

Your code snippets above missing the portion where you retrieve the JSON into the data that was later used by the JSONSerialization in viewDidLoad().
As example of a complete snippet, please check the question in this thread: How to get json to populate UITableView in Swift 3?