Expand/collapse section in UITableView in iOS

Question

Could somebody tell me the way to perform UITableView expandable/collapsible animations in sections of UITableView as below?

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Answer 1

I am adding this solution for completeness and showing how to work with section headers.

import UIKit

class ViewController: UIViewController, UITableViewDataSource, UITableViewDelegate {

    @IBOutlet var tableView: UITableView!
    var headerButtons: [UIButton]!
    var sections = [true, true, true]

    override func viewDidLoad() {
        super.viewDidLoad()
        tableView.dataSource = self
        tableView.delegate = self

        let section0Button = UIButton(type: .detailDisclosure)
        section0Button.setTitle("Section 0", for: .normal)
        section0Button.addTarget(self, action: #selector(section0Tapped), for: .touchUpInside)

        let section1Button = UIButton(type: .detailDisclosure)
        section1Button.setTitle("Section 1", for: .normal)
        section1Button.addTarget(self, action: #selector(section1Tapped), for: .touchUpInside)

        let section2Button = UIButton(type: .detailDisclosure)
        section2Button.setTitle("Section 2", for: .normal)
        section2Button.addTarget(self, action: #selector(section2Tapped), for: .touchUpInside)

        headerButtons = [UIButton]()
        headerButtons.append(section0Button)
        headerButtons.append(section1Button)
        headerButtons.append(section2Button)
    }

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

    func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        return sections[section] ? 3 : 0
    }

    func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
        let cellReuseId = "cellReuseId"
        let cell = UITableViewCell(style: .default, reuseIdentifier: cellReuseId)
        cell.textLabel?.text = "\(indexPath.section): \(indexPath.row)"
        return cell
    }

    func tableView(_ tableView: UITableView, viewForHeaderInSection section: Int) -> UIView? {
        return headerButtons[section]
    }

    func tableView(_ tableView: UITableView, heightForHeaderInSection section: Int) -> CGFloat {
        return 44
    }

    @objc func section0Tapped() {
        sections[0] = !sections[0]
        tableView.reloadSections([0], with: .fade)
    }

    @objc func section1Tapped() {
        sections[1] = !sections[1]
        tableView.reloadSections([1], with: .fade)
    }

    @objc func section2Tapped() {
        sections[2] = !sections[2]
        tableView.reloadSections([2], with: .fade)
    }

}

Link to gist: https://gist.github.com/pawelkijowskizimperium/fe1e8511a7932a0d40486a2669316d2c