Table Content disappears on Scroll in TableView with Custom Cell using Subview - Swift - swift

Question

I have a ViewController which uses multiple Subviews (HomeViewController, etc.) which can be selected via a Custom Tab Bar at the bottom of my app. Inside the HomeViewController there is a UIView containing a UITableView containing a Prototype Custom Cell with name and image.
import UIKit
class HomeViewController: UIViewController {
#IBOutlet weak var friendView: UITableView!
let friends = ["batman", "harsh", "ava", "sasha", "fatima", "alfred"]
override func viewDidLoad() {
super.viewDidLoad()
friendView.delegate = self
friendView.dataSource = self
friendView.allowsSelection = false
}
}
extension HomeViewController: UITableViewDelegate, UITableViewDataSource {
func tableView(_ tableView: UITableView, heightForRowAt indexPath: IndexPath) -> CGFloat {
return 120
}
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return friends.count
}
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = friendView.dequeueReusableCell(withIdentifier: "customCell") as! CustomCell
let friend = friends[indexPath.row]
cell.avatarImg.image = UIImage(named: friend)
cell.nameLbl.text = friend
return cell
}
}
Custom cell:
import UIKit
class CustomCell: UITableViewCell {
#IBOutlet weak var friendView: UIView!
#IBOutlet weak var nameLbl: UILabel!
#IBOutlet weak var avatarImg: UIImageView!
override func awakeFromNib() {
super.awakeFromNib()
// Initialization code
}
override func setSelected(_ selected: Bool, animated: Bool) {
super.setSelected(selected, animated: animated)
// Configure the view for the selected state
}
}
When I start the app, everything looks just fine. However, when I start scrolling inside the table, all data suddenly disappears. All relations between storyboard and code should be just fine. I think it might have got something to do with my need of using a Subview.
import UIKit
class ViewController: UIViewController {
#IBOutlet weak var tabBarView: UIView!
#IBOutlet weak var contentView: UIView!
override func viewDidLoad() {
super.viewDidLoad()
Design.makeCornersRound(view: tabBarView, radius: 10.0)
Timer.scheduledTimer(withTimeInterval: 0.1, repeats: false) { (timer) in
self.switchToHomeViewController()
}
}
#IBAction func onClickTabBar(_ sender: UIButton) {
let tag = sender.tag
if tag == 1 {
switchToIncomingsViewController()
}
else if tag == 2 {
switchToSpendingsViewController()
}
else if tag == 3 {
switchToHomeViewController()
}
else if tag == 4 {
switchToSavingsViewController()
}
else if tag == 5 {
switchToSettingsViewController()
}
}
func switchToHomeViewController() {
guard let Home = self.storyboard?.instantiateViewController(withIdentifier: "HomeViewController") as? HomeViewController else { return }
contentView.addSubview(Home.view)
Home.didMove(toParent: self)
}
...
}
Reference to the tutorial I have been trying to implement: https://www.youtube.com/watch?v=ON3Z0PXSoVk

Answer 1

In this function:
func switchToHomeViewController() {
// 1
guard let Home = self.storyboard?.instantiateViewController(withIdentifier: "HomeViewController") as? HomeViewController else { return }
// 2
contentView.addSubview(Home.view)
// 3
Home.didMove(toParent: self)
// 4
}
At 1 you create an instance of HomeViewController
at 2 you add its view to cotentView
at 3 you call didMove() ... but that doesn't do anything because you haven't added the controller to your hierarchy
at 4 your Home instance goes away, so the code in that controller no longer exists
You need to add the controller as a child controller.
As a side note, use lowerCase for variable names:
func switchToHomeViewController() {
// create an instance of HomeViewController
guard let homeVC = self.storyboard?.instantiateViewController(withIdentifier: "HomeViewController") as? HomeViewController else { return }
// add it as a child view controller
self.addChild(homeVC)
// add its view
contentView.addSubview(homeVC.view)
// here you should either set the view's frame or add constraints
// such as:
homeVC.view.frame = contentView.bounds
// inform the controller that it moved to a parent controller
homeVC.didMove(toParent: self)
}