在Swift中为json文件初始化字典数组

Question

I just started using Swift and I would like to display the result of parsing a JSON file in a UITableView . The problem comes from the initialization of my NSMutableArray news which will contain all the objects to display.

I have the Error :

error : "/Users/******/Documents/developper/******/*******
/NewsTableViewController.swift:79:22: 'NSMutableArray?' 
does not have a member named 'count'

Code is :

import UIKit

class NewsTableViewController: UITableViewController {

var bytes: NSMutableData?

// var news: NSArray = []

var news: NSMutableArray?

override func viewDidLoad() {
    super.viewDidLoad()

    // Uncomment the following line to preserve selection between presentations
    // self.clearsSelectionOnViewWillAppear = false

    // Uncomment the following line to display an Edit button in the navigation bar for this view controller.
    // self.navigationItem.rightBarButtonItem = self.editButtonItem()



        // this is our remote end point (similar to URLRequest in AS3)
    let request = NSURLRequest(URL: NSURL(string: "http://mangerdulion.com/wp-content/newsInnoven.json")!)

    // this is what creates the connection and dispatches the varios events to track progression, etc.
    let loader = NSURLConnection(request: request, delegate: self, startImmediately: true)

}
func connection(connection: NSURLConnection!, didReceiveData conData: NSData!) {
    self.bytes?.appendData(conData)
}
func connection(didReceiveResponse: NSURLConnection!, didReceiveResponse response: NSURLResponse!) {
    self.bytes = NSMutableData()
}

func connectionDidFinishLoading(connection: NSURLConnection!) {

    // we serialize our bytes back to the original JSON structure
    let jsonResult: Dictionary = NSJSONSerialization.JSONObjectWithData(self.bytes!, options: NSJSONReadingOptions.MutableContainers, error: nil) as Dictionary<String, AnyObject>

    // we grab the colorsArray element
    let results: NSArray = jsonResult["newsArray"] as NSArray

    self.news?.addObjectsFromArray(results)
    /*
    // we iterate over each element of the colorsArray array
    for item in results {
        // we convert each key to a String
        var titre: String = item["titreNews"] as String
        var date: String = item["dateNews"] as String
        var contenu: String = item["contenuNews"] as String
        println("\(titre): \(date):\(contenu)")

    }
 */

}

override func didReceiveMemoryWarning() {
    super.didReceiveMemoryWarning()
    // Dispose of any resources that can be recreated.
}

// MARK: - Table view data source



override func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
    // #warning Incomplete method implementation.
    // Return the number of rows in the section.

    //println(self.news?.count)

    return self.news.count

}


override func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
    let cell = tableView.dequeueReusableCellWithIdentifier("reuseIdentifier", forIndexPath: indexPath) as UITableViewCell




    let titre: NSDictionary = self.news[indexPath.row] as NSDictionary

    cell.textLabel?.text = titre["titreNews"] as? String
    println(cell.textLabel?.text)


    // Get the formatted price string for display in the subtitle
    let contenu: NSString = titre["contenuNews"] as NSString

    cell.detailTextLabel?.text = contenu


    return cell
}

Answer 1

Create a mutable array at the top of your class, and don't put any "?" or "!" after news.

var news: NSMutableArray = []

You also need to call reloadData on your table view at the end of the connectionDidFinishLoading method

Answer 2

Putting ? character at the end of your class while declaring a variable creates an Optional variable. Optional variables can be nil or have a value Optional(value). You have to unwrap the Optional to use it.

var news:NSMutableArray? creates an optional array.

items?.count will also return an optional Optional(Int). This cannot be returned in the UITableView count method.

I don't think you need to use an optional here. Instead you can use an empty array for convenience.

var news: NSMutableArray = []