Change App Icon in an iOS/iPadOS application.

AppIconChangeController.swift

//
//  AppIconChangeController.swift
//  Color Picker
//
//  Created by Swapnanil Dhol on 2/5/20.
//  Copyright © 2020 Swapnanil Dhol. All rights reserved.
//
import UIKit

class AppIconChangeController: UIViewController {

    @IBOutlet weak private var tableView: UITableView!

    private let appIcons = ["BlueIcon", "PurpleIcon", "BlackIcon", "RedIcon", "GreenIcon", "ios6logo","DefaultIcon"]
    private let appIconNames = ["Blue", "Purple", "Black", "Red", "Green", "iOS 6","Default"]

    override func viewDidLoad() {
        super.viewDidLoad()
        self.title = "app icons"
    }

    override func viewWillAppear(_ animated: Bool) {
        super.viewWillAppear(animated)
        self.tableView.delegate = self
        self.tableView.dataSource = self
    }

    private func setAppIcon(with name: String) {
        UIApplication.shared.setAlternateIconName(name) { error in
            assertionFailure("AppIconChangeController: Error while Changing App Icon. Error is \(error?.localizedDescription)")
        }
    }
}

extension AppIconChangeController: UITableViewDataSource {
    func numberOfSections(in tableView: UITableView) -> Int {
        return 1 //It Defaults to 1. No need to use this method. I just do it out of habit
    }
     func tableView(_ tableView: UITableView, heightForFooterInSection section: Int) -> CGFloat {
        return CGFloat.leastNormalMagnitude
    }

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

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

        let cell = tableView.dequeueReusableCell(withIdentifier: "cell", for: indexPath)
        cell.imageView?.layer.cornerRadius = 8
        cell.imageView?.image = UIImage(imageLiteralResourceName: appIcons[indexPath.row])
        cell.textLabel?.text = appIconNames[indexPath.row]
        return cell
    }
}

extension AppIconChangeController: UITableViewDelegate {

    func tableView(_ tableView: UITableView, heightForRowAt indexPath: IndexPath) -> CGFloat {
        return 110
    }
     func tableView(_ tableView: UITableView, heightForHeaderInSection section: Int) -> CGFloat {
        return section == 0 ? 10 : 6
      }

    func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
        UIImpactFeedbackGenerator().impactOccurred(intensity: 0.7)
        let section = indexPath.row
        switch section
        {
        case 0:
            setAppIcon(with: "AppIcon-2")
        case 1:
            setAppIcon(with: "AppIcon-3")
        case 2:
            setAppIcon(with: "AppIcon-4")
        case 3:
            setAppIcon(with: "AppIcon-5")
        case 4:
            setAppIcon(with: "AppIcon-6")
        case 5:
            setAppIcon(with: "AppIcon-7")
        case 6:
            UIApplication.shared.setAlternateIconName(nil) //Sets Default App Icon
        default:
            break
        }
        tableView.deselectRow(at: indexPath, animated: true)
    }
}