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
}

vadian · Accepted Answer

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.

How to populate my tableView in Swift 2 from JSON?

Answers (2)

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