Parsing JSON into tableview - ios

Question

I am receiving a JSON file from a remote server and I can display the result in a label. The JSON data is working fine when I call function processJSONData() and the tableview works fine with a simple array. How can I incorporate both to display the result from the JSON file in the tableview? Kindly look at the code below and edit. Many thanks:
import UIKit
class ViewController: UIViewController, UITableViewDelegate, UITableViewDataSource {
#IBOutlet weak var countryLabel: UILabel!
#IBOutlet weak var capitalLabel: UILabel!
override func viewDidLoad() {
super.viewDidLoad()
//processJSONData()
self.myTableView.registerClass(UITableViewCell.self,forCellReuseIdentifier: "cell")
self.myTableView.dataSource = self
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
}
func processJSONData(){
let urlPath = "http://dubaisinan.host22.com/service1.php"
let url : NSURL = NSURL(string: urlPath)!
let session = NSURLSession.sharedSession()
let task = session.dataTaskWithURL(url,completionHandler: {(data, respose, error) -> Void in
if error != nil {
println(error)
}
else {
self.abc(data)
}
})
task.resume()
}
func abc(data:NSData)
{
var parseError: NSError?
let result:AnyObject? = NSJSONSerialization.JSONObjectWithData(data, options: NSJSONReadingOptions.MutableContainers, error: &parseError);
if(parseError == nil){
if let dictResult = result as? NSArray{
dispatch_async(dispatch_get_main_queue()) {
self.countryLabel.text = dictResult[2]["Capital"] as? String
}
}
}
}
#IBOutlet weak var myTableView: UITableView!
var items = ["One","Two", "Three","Four"]
func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return items.count
}
func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
var cell:UITableViewCell = self.myTableView
.dequeueReusableCellWithIdentifier("cell") as UITableViewCell
cell.textLabel?.text = self.items[indexPath.row]
return cell
}
}

Answer 1

I don't see you assign your parsing result to global "items" and reload tableview with new data anywhere.
could be done here
if let dictResult = result as? NSArray{
self.items = dictResult
self.myTableView.reloadData()
///the rest of the code
}

Answer 2

You have to save the JSON data into a class-level variable, which you will define outside of any function, similar to how you defined "items". Assuming you have a list of countries with the capital of each, this might look like so:
var countryAndCapitalData = [(country: String, capital: String)]()
This could be improved by first defining a struct to contain your data:
struct CountryInfo
{
name: String
capital: String
init(name:String, capital:String)
{
self.name = name
self.capital = capital
}
}
which lets you define your data array as an array of CountryInfo:
var countryAndCapitalData = [CountryInfo]()
Then in your "abc" function (which I insist you rename to something like processCountryData), store the pairs of country name + capital name strings in countryAndCapitalData. For example:
countryAndCapitalData.append(CountryInfo(countryName, capitalName))
Use a For loop to loop through values in dictResult. Creating countryName and capitalName depends on the structure of your JSON, but from your example it might look like this:
for countryDictionary in dictResult[2]
{
if let countryName = countryDictionary["country"], let capitalName = countryDictionary["capital"]
{
countryAndCapitalData.append(CountryInfo(countryName, capitalName))
}
}
Then in tableView.cellForRowAtIndexPath, populate the cell label(s) with countryAndCapitalData[indexPath.row].name and countryAndCapitalData[indexPath.row].capital.
And finally, be sure to reload the table after the loop (thanks Eugene):
dispatch_async(dispatch_get_main_queue()) {
self.myTableView.reloadData()
}
Apologies for any compilation errors, as I'm typing this from a Windows machine.

Answer 3

You should update your items property in abc method call and then refresh the table:
func abc(data: NSData) {
// Do something with data
items = .. // processed data
}
var items: [String]? {
didSet {
NSOperationQueue.mainQueue.addOperationWithBlock {
self.tableView.reloadData()
}
}
}