Swift 3 Sort / Group JSON Data into Tableview with Sections

Question

I need to sort / group JSON Data into sections on a tableview.

Right now, the JSON data can't be easily altered so it needs to be re-sorted in Swift.

Basically, I would like it to count how many different DATES there are (which is just a string value) and sort the data based upon it. Then, the sections should be the different DATES with the respected articles in the rows.

The tableview should look like this:

**January 1, 2016**
- Article A 
     - Title
     - Author
     - ETC...
- Article C
     - Title
     - Author
     - ETC...
**February 2, 2016**
- Article B
     - Title
     - Author
     - ETC...

Right now the JSON looks something like:

[
    {
        “x_author”: "",
        "excerpt" : 
            "rendered": “”
        },
        "x_featured_media" : "",
        "title": {
            "rendered": “A”
        },
        "x_date": “January 1, 2016",
    },
    {
        “x_author”: "",
        "excerpt" : 
            "rendered": “”
        },
        "x_featured_media" : "",
        "title": {
            "rendered": “B”
        },
        "x_date": “February 1, 2016",
    },
    {
        “x_author”: "",
        "excerpt" : 
            "rendered": “”
        },
        "x_featured_media" : "",
        "title": {
            "rendered": “C”
        },
        "x_date": “January 1, 2016",
    },
]

The ViewController looks like this:

import UIKit

class ViewController: UIViewController, UITableViewDelegate, UITableViewDataSource {
    @IBOutlet var tableview: UITableView!

    var articles: [Article]? = []

        override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view, typically from a nib.
        fetchArticles()
    }

    func fetchArticles() {
        let urlRequest = URLRequest(url: URL(string: "SITE")!)
        let task = URLSession.shared.dataTask(with: urlRequest) { (data, response, error) in
            if error != nil {
                print(error)
                return
            }
            self.articles = [Article]()
            do {
                let json = try JSONSerialization.jsonObject(with: data!, options: .mutableContainers) as? AnyObject
                if let articlesFromJson = json as? [[String : AnyObject ]] {
                    for articleFromJson in articlesFromJson {
                        let article = Article()
                          if let title = articleFromJson["title"]?["rendered"] as? String, 
                              let author = articleFromJson["x_author"] as? String, 
                              let desc = articleFromJson["excerpt"]?["rendered"] as? String, 
                              let url = articleFromJson["link"] as? String, 
                              let urlToImage = articleFromJson["x_featured_media"] as? String, 
                              let date = articleFromJson["x_date"] as? String {

                            article.author = author
                            article.desc = desc
                            article.headline = title
                            article.url = url
                            article.imageUrl = urlToImage
                            article.date = date
                        }
                        self.articles?.append(article)
                     }
                }
                DispatchQueue.main.async {
                    self.tableview.reloadData()
                }
            } catch let error {
                print(error)
            }
        }
        task.resume()
    }

    func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
        let cell = tableView.dequeueReusableCell(withIdentifier: "articleCell", for: indexPath) as! articleCell
        cell.title.text = self.articles?[indexPath.item].headline
        cell.desc.text = self.articles?[indexPath.item].desc
        cell.author.text = self.articles?[indexPath.item].author
        cell.date.text = self.articles?[indexPath.item].date    
        cell.imgView.downloadImage(from: (self.articles?[indexPath.item].imageUrl!)!)
        return cell
    }

    func numberOfSections(in tableView: UITableView) -> Int {
        return 1
    }

    func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        return self.articles?.count ?? 0
    }

    func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
        let webVC = UIStoryboard.init(name: "Main", bundle: nil).instantiateViewController(withIdentifier: "web") as! WebviewViewController
        webVC.url = self.articles?[indexPath.item].url
        self.present(webVC, animated: true, completion: nil)
    }
}

The Article class looks like:

import UIKit

class Article: NSObject {
    var headline: String?
    var desc: String?
    var author: String?
    var url: String?
    var content: String?
    var imageUrl: String?
    var date: String?
}

How do I go about doing this?

EDIT 1:

Following the advice of dmorrow, the view controller now looks like this:

    struct Issue {
    let dateName: String?
    var articles: [Article]?
}
struct Article {
    var headline: String?
    var desc: String?
    var author: String?
    var url: String?
    var imageUrl: String?
    var date: String?
}

var groupedArticles = [Issue]()

    override func viewDidLoad() {
    super.viewDidLoad()
    // Do any additional setup after loading the view, typically from a nib.
    fetchArticles()
}

func fetchArticles() {
    let urlRequest = URLRequest(url: URL(string: "SITE")!)
    let task = URLSession.shared.dataTask(with: urlRequest) { (data, response, error) in
        if error != nil {
            print(error)
            return
        }
        do {
            let json = try JSONSerialization.jsonObject(with: data!, options: .mutableContainers) as? AnyObject
            if let articlesFromJson = json as? [[String : AnyObject ]] {
                for articleFromJson in articlesFromJson {

                        self.groupedArticles.append(Issue(dateName: (articleFromJson["x_date"] as! String), articles: [Article(headline: (articleFromJson["title"] as! String), desc: (articleFromJson["excerpt"] as! String), author: (articleFromJson["x_author"] as! String), url: (articleFromJson["x_featured_media"] as! String), imageUrl: (articleFromJson["x_featured_media"] as! String), date: (articleFromJson["x_date"] as! String))]))                    
                   }
            }
            DispatchQueue.main.async {
                self.tableview.reloadData()
            }
        } catch let error {
            print(error)
        }
    }
    task.resume()
}

func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
    let cell = tableView.dequeueReusableCell(withIdentifier: "articleCell", for: indexPath) as! articleCell        
    cell.title.text = self.groupedArticles[indexPath.section].articles?[indexPath.row].headline
    cell.desc.text = self.groupedArticles[indexPath.section].articles?[indexPath.row].desc
    cell.author.text = self.groupedArticles[indexPath.section].articles?[indexPath.row].author
    cell.date.text = self.groupedArticles[indexPath.section].articles?[indexPath.row].date

    cell.imgView.downloadImage(from: (self.groupedArticles[indexPath.section].articles?[indexPath.row].imageUrl!)!)
    return cell
}

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

func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
    return groupedArticles[section].articles?.count ?? 0
}

func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
    let webVC = UIStoryboard.init(name: "Main", bundle: nil).instantiateViewController(withIdentifier: "web") as! WebviewViewController
    webVC.url = self.groupedArticles[indexPath.section].articles?[indexPath.row].url
    self.present(webVC, animated: true, completion: nil)
}

HOWEVER, getting error at:

self.groupedArticles.append(Issue(dateName: (articleFromJson["x_date"] as! String), articles: [Article(headline: (articleFromJson["title"] as! String), desc: (articleFromJson["excerpt"] as! String), author: (articleFromJson["x_author"] as! String), url: (articleFromJson["x_featured_media"] as! String), imageUrl: (articleFromJson["x_featured_media"] as! String), date: (articleFromJson["x_date"] as! String))]))

"Could not cast value of type '__NSDictionaryM' (0x106a35260) to 'NSString' (0x1031d9c40)."

Was this the right track? How do I solve this?

---

EDIT 2

Updated fetchArticles function:

func fetchArticles() {
    let urlRequest = URLRequest(url: URL(string: "X")!)
    let task = URLSession.shared.dataTask(with: urlRequest) { (data, response, error) in
        if error != nil {
            print(error)
            return
        }
        do {
            let json = try JSONSerialization.jsonObject(with: data!, options: .mutableContainers) as? AnyObject
            if let articlesFromJson = json as? [[String : AnyObject]] {
                for articleFromJson in articlesFromJson {
                    // Get All Articles
                    var articleEntries = [Issue]()

                    articleEntries.append(Issue(dateName: (articleFromJson["x_date"] as! String), articles: [Article(headline: (articleFromJson["title"]?["rendered"] as! String), desc: (articleFromJson["excerpt"]?["rendered"] as! String), author: (articleFromJson["x_author"] as! String), url: (articleFromJson["x_featured_media"] as! String), imageUrl: (articleFromJson["x_featured_media"] as! String), date: (articleFromJson["x_date"] as! String))]))

                    // SORT Articles by KEY of X_Date(String)
                    var groupedArts = [String: [Issue]]()
                    var groupedKeys = Array<String>()

                    for article in articleEntries {
                        let index = (article.dateName?.startIndex)!..<(article.dateName?.endIndex)!
                        let keys = String(describing: article.dateName?[index])
                        if groupedArts[keys] != nil {
                            groupedArts[keys]?.append(article)
                            print("this array exists")
                        } else {
                            groupedArts[keys] = [article]
                            groupedKeys.append(keys)
                            print("this array does not exist")
                        }
                    }
                    print(groupedArts)
                    print(groupedKeys)
                }
            }
            DispatchQueue.main.async {
                self.tableview.reloadData()
            }
        } catch let error {
            print(error)
        }
    }
    task.resume()
}

From my understanding, I should be parsing the entries then re-ordering them using something similar to the sample code but its producing results individually:

["Optional(\"February 14, 2016\")": [Journal.ViewController.Issue(dateName: Optional("February 14, 2016"), articles: Optional([Journal.ViewController.Article(headline: Optional("Case File: Shocking out with severe hypoxia"), desc: Optional("ABC"), author: Optional("AUTHOR"), url: Optional("X"), imageUrl: Optional("X"), date: Optional("February 14, 2016"))]))]] ["Optional(\"February 14, 2016\")"]

and so forth for each article. I tried to parse the articles in the IF statement but that crashes everything. What can I do?

Answer 1

In general, you'll need to create an array of Section for your datasource.

struct Section {
     let date:Date
     var articles:[Article]
}

var groupedArticles = [Section]()

While you are parsing your JSON into Article, you should be storing them in this array. Article should probably be a struct, and you should look into https://github.com/Hearst-DD/ObjectMapper or https://github.com/SwiftyJSON/SwiftyJSON

Then you can use these methods

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

func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
    return groupedArticles[section].articles.count ?? 0
}

See this similar answer - https://stackoverflow.com/a/42277283/1189470