From 2f22931e0a4617dbd218a92c02bc9e83649ee6f7 Mon Sep 17 00:00:00 2001
From: Nicholas Tay <nick@windblume.net>
Date: Mon, 14 Mar 2022 16:05:46 +1100
Subject: Grouping items together by year

https://www.ralfebert.com/ios-examples/uikit/uitableviewcontroller/grouping-sections/
---
 foray/ForayTableViewController.swift | 59 ++++++++++++++++++++++++++++++------
 1 file changed, 49 insertions(+), 10 deletions(-)

(limited to 'foray')

diff --git a/foray/ForayTableViewController.swift b/foray/ForayTableViewController.swift
index 66e9274..e283c9d 100644
--- a/foray/ForayTableViewController.swift
+++ b/foray/ForayTableViewController.swift
@@ -8,44 +8,80 @@
 import UIKit
 
 struct MyItem {
+    var releaseDate: Date
     var id: String
     var name: String
 }
 
+struct YearSection {
+    var year: Date
+    var items: [MyItem]
+}
+
 class ForayTableViewCell: UITableViewCell {
     @IBOutlet weak var cellItemName: UILabel!
     @IBOutlet weak var cellItemSubtitle: UILabel!
     @IBOutlet weak var cellItemImage: UIImageView!
 }
 
+// copied from sample project
+private func parseDate(_ str : String) -> Date {
+    let dateFormat = DateFormatter()
+    dateFormat.dateFormat = "yyyy-MM-dd"
+    return dateFormat.date(from: str)!
+}
+
+private func firstDayOfYear(date: Date) -> Date {
+    let calendar = Calendar.current
+    let components = calendar.dateComponents([.year], from: date)
+    return calendar.date(from: components)!
+}
+
 class ForayTableViewController: UITableViewController {
     
     // MARK: - Static data TEMP
     
     let items = [
-        MyItem(id: "mh", name: "Miners Helmet"),
-        MyItem(id: "it", name: "Inner Tube"),
-        MyItem(id: "tbg", name: "Toboggan"),
-        MyItem(id: "spy", name: "Spy Phone"),
-        MyItem(id: "bnb", name: "Black Ninja Belt"),
+        MyItem(releaseDate: parseDate("2006-05-26"), id: "mh", name: "Miners Helmet"),
+        MyItem(releaseDate: parseDate("2010-05-01"), id: "it", name: "Inner Tube"),
+        MyItem(releaseDate: parseDate("2009-04-24"), id: "tbg", name: "Toboggan"),
+        MyItem(releaseDate: parseDate("2006-03-29"), id: "spy", name: "Spy Phone"),
+        MyItem(releaseDate: parseDate("2008-11-18"), id: "bnb", name: "Black Ninja Belt"),
     ]
     
+    var sections = [YearSection]()
+    
+    // MARK: - On load
+    
+    override func viewDidLoad() {
+        super.viewDidLoad()
+        
+        let groups = Dictionary(grouping: self.items) { (item) in
+            return firstDayOfYear(date: item.releaseDate)
+        }
+        self.sections = groups.map { (key, values) in
+            return YearSection(year: key, items: values)
+        }
+        // Sort the sections from oldest year to newest
+        self.sections.sort { (lhs, rhs) in lhs.year < rhs.year }
+    }
+    
     // MARK: - Table view data source
 
     override func numberOfSections(in tableView: UITableView) -> Int {
         // Returns number of sections for table
-        return 1
+        return self.sections.count
     }
 
     override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
-        // Returns number of rows for table
-        return items.count
+        // Returns number of rows for table's section
+        return self.sections[section].items.count
     }
 
     override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
         let cell = tableView.dequeueReusableCell(withIdentifier: "ForayCell", for: indexPath) as! ForayTableViewCell
 
-        let item = items[indexPath.row]
+        let item = self.sections[indexPath.section].items[indexPath.row]
         cell.cellItemName?.text = item.name
         cell.cellItemSubtitle?.text = "Item ID: \(item.id)"
         cell.cellItemImage?.image = UIImage(named: item.id)
@@ -54,6 +90,9 @@ class ForayTableViewController: UITableViewController {
     }
     
     override func tableView(_ tableView: UITableView, titleForHeaderInSection section: Int) -> String? {
-        return "Section \(section)"
+        let section = self.sections[section]
+        let dateFormatter = DateFormatter()
+        dateFormatter.dateFormat = "yyyy"
+        return "Released in " + dateFormatter.string(from: section.year)
     }
 }
-- 
cgit