How to add section to UITableView programmatically in swift 3

Question

I need to list contents of a json and sort by date (sections). So far, I managed to get the json successfully and list the main content (name and hour) but I need to sort by date as section.

EDIT: If I have more than 100 "items" (json objects) and in some the date is repeated (as in the first two objects of the json below), then I want those items to be in a section with the date as the title of the each section.

Json:

[
{"date_raw":"1/18/2017 12:00:00 AM","name":"Hello 2","hour":"12:00 - 14:00","audio_url":"http://example.com/file2.mp4"},
{"date_raw":"1/18/2017 12:00:00 AM","name":"Hello 1","hour":"10:00 - 12:00","audio_url":"http://example.com/file1.mp4"},
{"date_raw":"1/17/2017 12:00:00 AM","name":"Hello","hour":"10:00 - 12:00","audio_url":"http://example.com/file.mp4"},
{"date_raw":"1/16/2017 12:00:00 AM","name":"Hello","hour":"10:00 - 12:00","audio_url":"http://example.com/file.mp4"}
]

Main Class:

class MyVC: UIViewController, UITableViewDelegate, UITableViewDataSource {

    @IBOutlet weak var tableView: UITableView!

    // date_raw
    var section: [String] = []

    // date_raw, name, hour, audio_url
    var items: [(String, String, String, String)] = []

    var dateV:String = ""

    func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        return items.count

    }


    func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {

        let cell:UITableViewCell = UITableViewCell(style: UITableViewCellStyle.subtitle, reuseIdentifier: "cell")

        cell.textLabel!.text = items[indexPath.row].1 // get name
        cell.detailTextLabel!.text = items[indexPath.row].2 // get hour

        return cell;
    }


    func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
        print(items[indexPath.row])

    }


    func getJson(_ url:String) {

        // Asynchronous Http call to your api url, using NSURLSession:
        URLSession.shared.dataTask(with: URL(string: url)!, completionHandler: { (data, response, error) -> Void in

            if error != nil || data == nil {

                print("error")

            } else {


                do {

                    let json:NSArray = try (JSONSerialization.jsonObject(with: data!, options:JSONSerialization.ReadingOptions.mutableContainers) as? NSArray)!

                    for i in 0...json.count-1 {

                        if let date_raw = (json[i] as AnyObject).value(forKey: "date_raw") as? String,
                            let name = (json[i] as AnyObject).value(forKey: "name") as? String,
                            let hour = (json[i] as AnyObject).value(forKey: "hour") as? String,
                            let audio_url = (json[i] as AnyObject).value(forKey: "audio_url") as? String {

                            if date_raw != self.dateV {
                                self.section.append(date_raw)
                                self.dateV = date_raw;
                            }

                            self.items.append(date_raw, name, hour, audio_url)

                        }
                    }//End for

                    //print(self.section)
                    self.do_table_refresh();

                } catch {
                    print("error")
                }

            }

        }).resume()
        // TODO: butonu disable et
    }


    func do_table_refresh() {
        DispatchQueue.main.async(execute: {
            self.tableView.reloadData()
            self.tableView.isHidden = false
            return
        })
    }


    override func viewDidLoad() {
        super.viewDidLoad()

        tableView.delegate      =   self
        tableView.dataSource    =   self
        tableView.register(UITableViewCell.self, forCellReuseIdentifier: "cell")
        tableView.isHidden = true

        getJson("http://example.com/my-json-file.json")

    }


}

Answer 1

Here you have code example (paste in Playground and have fun)

//: Playground - noun: a place where people can play

import UIKit
import PlaygroundSupport

PlaygroundPage.current.needsIndefiniteExecution = true

struct Model {
    let date: String
    let name: String
    let hour: String
    let audioUrl: String
}

class HelpViewController: UITableViewController {

    let jsonData = "[{\"date_raw\":\"1/18/2017 12:00:00 AM\",\"name\":\"Hello 2\",\"hour\":\"12:00 - 14:00\",\"audio_url\":\"http://example.com/file2.mp4\"},{\"date_raw\":\"1/18/2017 12:00:00 AM\",\"name\":\"Hello 1\",\"hour\":\"10:00 - 12:00\",\"audio_url\":\"http://example.com/file1.mp4\"},{\"date_raw\":\"1/17/2017 12:00:00 AM\",\"name\":\"Hello\",\"hour\":\"10:00 - 12:00\",\"audio_url\":\"http://example.com/file.mp4\"},{\"date_raw\":\"1/16/2017 12:00:00 AM\",\"name\":\"Hello\",\"hour\":\"10:00 - 12:00\",\"audio_url\":\"http://example.com/file.mp4\"}]"

    var data = [String: [Model]]()
    var keys = [String]()

    override func viewDidLoad() {
        super.viewDidLoad()

        tableView.register(UITableViewCell.self, forCellReuseIdentifier: "TestCell")
        loadData()
    }

    func loadData() {
        guard let jsonData = jsonData.data(using: .utf8),
            let json = try? JSONSerialization.jsonObject(with: jsonData, options: .allowFragments),
            let jsonArray = json as? [[String: Any]]
        else { return }

        // Map json to array of Models
        let mappedData = jsonArray.flatMap { (elem) -> Model? in
            guard let dateRaw = elem["date_raw"] as? String,
                let name = elem["name"] as? String,
                let hour = elem["hour"] as? String,
                let audioUrl = elem["audio_url"] as? String else { return nil }

            return Model(date: dateRaw, name: name, hour: hour, audioUrl: audioUrl)
        }

        // Create a dictionary from array of Models
        // Each key == section (model.date), will contain array of associated with this key models
        data = mappedData.reduce([String: [Model]]()) { (result, element) -> [String: [Model]] in

            var res = result
            if res[element.date] == nil {
                res[element.date] = [element]
                self.keys += [element.date]
            } else {
                res[element.date]! += [element]
            }
            return res
        }

        tableView.reloadData()
    }

    override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        if keys.count < 1 { return 0 }

        let key = keys[section]
        return data[key]?.count ?? 0
    }

    override func numberOfSections(in tableView: UITableView) -> Int {
        return keys.count
    }

    override func tableView(_ tableView: UITableView, titleForHeaderInSection section: Int) -> String? {
        return keys[section]
    }

    override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
        let cell = tableView.dequeueReusableCell(withIdentifier: "TestCell", for: indexPath)

        let key = keys[indexPath.section]
        let model = data[key]?[indexPath.row]
        if let model = model {
            cell.textLabel?.text = model.name
        }

        return cell
    }

}

let helpViewController = HelpViewController()
helpViewController.view.frame = CGRect(x: 0, y: 0, width: 320, height: 400)

PlaygroundPage.current.liveView = helpViewController.view