How to populate my tableView in Swift 2 from JSON?

Question

A new programmer here. How would I populate my tableView from this JSON?
My first problem is the JSON Serialization and then plugging it in the tableView.

Code

import UIKit

class LegislatorsTableVC: UITableViewController {

// MARK: Variables & Outlets
private let cellIdentifer = "cellReuse"

// MARK: View Did Load
override func viewDidLoad() {
    super.viewDidLoad()

    // Creating Congfiguration Object // Session Is Created // Getting Info/Data
    let configuration = NSURLSessionConfiguration.defaultSessionConfiguration()
    let session = NSURLSession(configuration: configuration)
    let apiKey = "https://congress.api.sunlightfoundation.com/legislators?apikey=xxxxxxxxxxxxxxxxxxxxx&all_legislators=true&per_page=all"

    if let url = NSURL(string: apiKey) {
        // Spawning Task To Retrieve JSON Data
        session.dataTaskWithURL(url, completionHandler: { (data, response, error) -> Void in
            // Checking For Error
            if let error = error {
                print("The error is: \(error)")
                return
            }
            // Response
            if let httpResponse = response as? NSHTTPURLResponse where httpResponse.statusCode == 200, let data = data {
                print("Status Code: \(httpResponse.statusCode)")
                // self.JSONSerialization(data)
            }
        }).resume()
    }
} // End Of View Did Load

// JSON Serialization Function With SwiftyJSON.swift
private func JSONSerialization(data: NSData){

    // I See this Gets A Status Code 200 And Then I'm Lost.
    do {
        let json = try NSJSONSerialization.JSONObjectWithData(data, options: .MutableContainers) as! [String: AnyObject]

    } catch {
        print("Error Serializing JSON Data: \(error)")
    }
} // End Of JSONSerialization



// MARK: - Table view data source
// Number Of Sections
override func numberOfSectionsInTableView(tableView: UITableView) -> Int {
    // #warning Incomplete implementation, return the number of sections
    return 1
} // End Of Number Of Sections

// Number Of Rows In Section
override func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
    // #warning Incomplete implementation, return the number of rows
    return 15
} // End Of Number Of Rows In Section

// Cell For Row At Index Path
override func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
    let cell = tableView.dequeueReusableCellWithIdentifier(cellIdentifer, forIndexPath: indexPath) as! LegislatorTVCell

    // Configure the cell...
    cell.name.text = "Name"
    cell.title.text = "Title"
    cell.party.text = "Party"

    return cell
} // End Of Cell For Row At Index Path
}

Answer 1

• Create a custom class Person outside the view controller

   class Person { var firstName = "" var lastName = "" var title = "" var party = "" } 

• Create an array of Person in the view controller

   var people = [Person]() 

• The JSON has a key results which contains an array of dictionaries.
  In viewDidLoad parse the JSON and create Person instances. Finally reload the table view.

   override func viewDidLoad() { super.viewDidLoad() // Creating Congfiguration Object // Session Is Created // Getting Info/Data let configuration = NSURLSessionConfiguration.defaultSessionConfiguration() let session = NSURLSession(configuration: configuration) let apiKey = "https://congress.api.sunlightfoundation.com/legislators?apikey=xxxxxxxxxxxxxxxxxx&all_legislators=true&per_page=all" if let url = NSURL(string: apiKey) { // Spawning Task To Retrieve JSON Data session.dataTaskWithURL(url, completionHandler: { (data, response, error) -> Void in // Checking For Error if error != nil { print("The error is: \\(error!)") return } else if let jsonData = data { do { let parsedJSON = try NSJSONSerialization.JSONObjectWithData(jsonData, options: []) as! [String:AnyObject] guard let results = parsedJSON["results"] as? [[String:AnyObject]] else { return } for result in results { let person = Person() person.firstName = result["first_name"] as! String person.lastName = result["last_name"] as! String person.party = result["party"] as! String person.title = result["title"] as! String self.people.append(person) } dispatch_async(dispatch_get_main_queue()) { self.tableView.reloadData() } } catch let error as NSError { print(error) } } }).resume() } } // End Of View Did Load 

• The table view delegate methods look very clear when using a custom class.
  Since cellForRowAtIndexPath is called very often the code is quite effective.

   override func numberOfSectionsInTableView(tableView: UITableView) -> Int { return 1 } override func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int { return people.count } override func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell { let cell = tableView.dequeueReusableCellWithIdentifier(cellIdentifer, forIndexPath: indexPath) as! LegislatorTVCell let person = people[indexPath.row] cell.name.text = person.firstName + " " + person.lastName cell.title.text = person.title cell.party.text = person.party return cell } // End 

Of course I couldn't test the code but this might be a starting point.

Answer 2

Basically what you want to do is introduce a new variable to your class, for example jsonDict like so:

class LegislatorsTableVC: UITableViewController {
    var jsonDict:Dictionary<String,AnyObject>?
    // further code

And then - you almost got it right already - save your JSON serialization into that in your JSONSerialization function. (which I would rename to parseJSON or something like that to avoid confusion) like so:

do {
    jsonDict = try NSJSONSerialization.JSONObjectWithData(data, options: .MutableContainers) as! [String: AnyObject]

} catch {
    print("Error Serializing JSON Data: \(error)")
}

So then you can return the right values to your tableView data source :

// MARK: - Table view data source
override func numberOfSectionsInTableView(tableView: UITableView) -> Int {
    return jsonDict["your JSON key"].count ?? 0
}

override func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
    return jsonDict["your JSON key"]["items"].count ?? 0
}

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

    let item = jsonDict["your JSON key"][indexPath.row]

    // Configure the cell...
    cell.name.text = item["name"]
    cell.title.text = item["title"]
    cell.party.text = item["party"]

    return cell
}

Naming is a little confusing, as I don't know the layout of your JSON, but replace your JSON key with your path to the data of course.