How to transfer data from NSArray to String in Swift? - arrays

Question

I have to put data in tableview, but even tough I get info from JSON, I can't pass data to postTitle variable. Why is that? Here is my code:
import UIKit
class ViewController: UIViewController, UITableViewDelegate, UITableViewDataSource {
var postTitle = [AnyObject]()
override func viewDidLoad() {
super.viewDidLoad()
var baseURL = "https://hacker-news.firebaseio.com/v0/topstories.json"
// https://hacker-news.firebaseio.com/v0/item/9324191.json
if let url = NSURL(string: baseURL) {
var taskURL = NSURLSession.sharedSession().dataTaskWithURL(url, completionHandler: { (data: NSData!, response: NSURLResponse!, error: NSError!) -> Void in
if error != nil {
println("Error: \(error.localizedDescription)")
} else {
var jsonError: NSError?
if let topStories = NSJSONSerialization.JSONObjectWithData(data, options: NSJSONReadingOptions.MutableContainers, error: &jsonError) as? NSArray {
self.postTitle.append(topStories)
}
}
})
taskURL.resume()
}
}
func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
println(postTitle.count)
return postTitle.count
}
func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
var cell = UITableViewCell()
println(self.postTitle)
// cell.textLabel?.text = postTitle[indexPath.row]
return cell
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
}

Answer 1

topStories is an NSArray, but you are appending it to the postTitle array (which is of type [AnyObject]). Array.append adds a single item to the array. So you will have added one entry, an NSArray of a bunch of post IDs, to your postTitle array.
I am guessing what you want is to add the contents of topStories to postTitle? In which case you want to use the extend rather than the append method:
self.postTitle.extend(topStories)

Answer 2

Given that you apparently reload ALL the titles with each request, you could just as easily do this: self.titles = topStories
I just built a test app this way and it worked perfectly fine.
PS: self.postTitle.append would have yielded the wrong result anyway, as it would also append titles you already have in your array. The method you probably should be using would be self.postTitle.join as it uses intersection.

Answer 3

So the other guy from Reddit help me out. I was missing few things. First was data type Int, which needs to be passed to instance variable, and second was UITableView: here is working solution. Hope this will help someone.
import UIKit
class ViewController: UITableViewController, UITableViewDelegate, UITableViewDataSource {
var postTitles = [Int]()
override func viewDidLoad() {
super.viewDidLoad()
var baseURL = "https://hacker-news.firebaseio.com/v0/topstories.json"
if let url = NSURL(string: baseURL) {
var taskURL = NSURLSession.sharedSession().dataTaskWithURL(url, completionHandler: { (data: NSData!, response: NSURLResponse!, error: NSError!) -> Void in
if error != nil {
println("Error: \(error.localizedDescription)")
} else {
var jsonError: NSError?
if let topStories = NSJSONSerialization.JSONObjectWithData(data, options: NSJSONReadingOptions.MutableContainers, error: &jsonError) as? [Int] {
self.postTitles = Array(topStories[0...9])
// Reload the table with our new results!
self.tableView.reloadData()
}
}
})
taskURL.resume()
}
}
override func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return postTitles.count
}
override func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCellWithIdentifier("Cell") as UITableViewCell
let postTitle = String(self.postTitles[indexPath.row])
cell.textLabel?.text = postTitle
return cell
}
}