How to display label after scrolling ? about stretchheader HOT 3 CLOSED

import UIKit

class Demo1Controller: UIViewController, UITableViewDataSource, UITableViewDelegate {

    var header : StretchHeader!
    var tableView : UITableView!
    var navigationView = UIView()
    
    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
    }
    
    override func viewWillAppear(_ animated: Bool) {
        super.viewWillAppear(animated)
        self.navigationController?.setNavigationBarHidden(true, animated: true)
        self.navigationController?.interactivePopGestureRecognizer?.delegate = nil;
    }
    
    override func viewDidLoad() {
        super.viewDidLoad()
        
        tableView = UITableView(frame: view.bounds, style: .plain)
        tableView.dataSource = self
        tableView.delegate = self
        view.addSubview(tableView)
        
        tableView.register(UITableViewCell.self, forCellReuseIdentifier: "TableViewCell")
        setupHeaderView()
        
        // NavigationHeader
        let navibarHeight : CGFloat = navigationController!.navigationBar.bounds.height
        let statusbarHeight : CGFloat = UIApplication.shared.statusBarFrame.size.height
        navigationView = UIView()
        navigationView.frame = CGRect(x: 0, y: 0, width: view.frame.size.width, height: navibarHeight + statusbarHeight)
        navigationView.backgroundColor = UIColor(red: 121/255.0, green: 193/255.0, blue: 203/255.0, alpha: 1.0)
        navigationView.alpha = 0.0
        view.addSubview(navigationView)
        
        // I will add this (navigationbar titlelabel)
        let label = UILabel()
        label.frame = CGRect(x: 0, y: statusbarHeight, width: view.frame.size.width, height: navibarHeight)
        label.text = "navigation title";
        label.textAlignment = .center
        label.textColor = UIColor.white
        navigationView.addSubview(label)
        
        let button = UIButton(type: .custom)
        button.frame = CGRect(x: 10, y: 20, width: 44, height: 44)
        button.setImage(UIImage(named: "navi_back_btn")?.withRenderingMode(.alwaysTemplate), for: UIControlState())
        button.tintColor = UIColor.white
        button.addTarget(self, action: #selector(Demo1Controller.leftButtonAction), for: .touchUpInside)
        view.addSubview(button)
    }
    
    func setupHeaderView() {
        
        let options = StretchHeaderOptions()
        options.position = .fullScreenTop
        
        header = StretchHeader()
        header.stretchHeaderSize(headerSize: CGSize(width: view.frame.size.width, height: 220),
            imageSize: CGSize(width: view.frame.size.width, height: 220),
            controller: self,
            options: options)
        header.imageView.image = UIImage(named: "photo_sample_05")
        
        // custom
        let label = UILabel()
        label.frame = CGRect(x: 10, y: header.frame.size.height - 40, width: header.frame.size.width - 20, height: 40)
        label.textColor = UIColor.white
        label.text = "StrechHeader Demo"
        label.font = UIFont.boldSystemFont(ofSize: 16)
        header.addSubview(label)
        
        tableView.tableHeaderView = header
    }
    
    // MARK: - Selector
    func leftButtonAction() {
        self.navigationController?.popViewController(animated: true)
    }
    
    // MARK: - ScrollView Delegate
    func scrollViewDidScroll(_ scrollView: UIScrollView) {
        header.updateScrollViewOffset(scrollView)
      
        // NavigationHeader alpha update
        let offset : CGFloat = scrollView.contentOffset.y
        if (offset > 50) {
            let alpha : CGFloat = min(CGFloat(1), CGFloat(1) - (CGFloat(50) + (navigationView.frame.height) - offset) / (navigationView.frame.height))
            navigationView.alpha = CGFloat(alpha)
            
        } else {
            navigationView.alpha = 0.0;
        }
    }
    
    // MARK: - Table view data source
    func numberOfSections(in tableView: UITableView) -> Int {
        // #warning Incomplete implementation, return the number of sections
        return 1
    }
    
    func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        // #warning Incomplete implementation, return the number of rows
        return 20
    }
    
    func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
        let cell = tableView.dequeueReusableCell(withIdentifier: "TableViewCell", for: indexPath)
        cell.textLabel?.text = "index -- \((indexPath as NSIndexPath).row)"
        return cell
    }
}