How to populate my tableView in Swift 2 from JSON? - ios

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.