Unable to use cell from XIB in tableView - ios

Question

Here's my DisruptionsViewController which has the tableView. the function setUp() is used in another ViewController class to set up the DisruptionsViewController.
public class DisruptionsInfoViewController: UIViewController {
#IBOutlet weak var tableView: UITableView!
public override func viewDidLoad() {
super.viewDidLoad()
self.setUp()
tableView.dataSource = self
tableView.delegate = self
tableView.register(UINib(nibName: "DisruptionInfoTableViewCell", bundle: nil), forCellReuseIdentifier: "disruptionsInfoTableViewCell")
}
private func loadFromNib() -> UIView? {
let nibName = String(describing: DisruptionsInfoViewController.self)
let nib = UINib(nibName: nibName, bundle: Bundle(for: type(of: self)))
return nib.instantiate(withOwner: self, options: nil).first as? UIView
}
public func setUp() {
guard let disruptionsInfoViewController = self.loadFromNib() else { return }
disruptionsInfoViewController.frame = self.view.bounds
}
}
extension DisruptionsInfoViewController: UITableViewDataSource, UITableViewDelegate {
public func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return 2
}
public func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
guard let cell = tableView.dequeueReusableCell(withIdentifier: "disruptionsInfoTableViewCell", for: indexPath) as? DisruptonInfoTableViewCell else { return UITableViewCell() }
return cell
}
}
Here's the tableViewCell class.
import UIKit
class DisruptonInfoTableViewCell: UITableViewCell {
#IBOutlet weak var testLabel: UILabel!
}
I can see the tableView in the view debugger, but unable to see it in the view as the tableViewCell is not registered for some reason.
Here's how I am using it in another controller's delegate method
func tableView(_ tableView: UITableView, viewForHeaderInSection section: Int) -> UIView? {
guard let viewModel = presenter.headerViewModel(for: section) else { return nil }
let dateSummaryView = DateSummaryView(frame: .zero)
dateSummaryView.setup(with: viewModel)
let disruptionsViewController = DisruptionsInfoViewController()
return disruptionsViewController.view
}
Does anyone know where the problem could be?
I tried following tutorials from YouTube and other articles, they use the same approach but for some reason it doesn't work for me.

Answer 1

First, as mentioned in the comments, nothing in your setUp() is doing anything, so it can be removed.
The reason you are not seeing your table view rows in your other table's section header views is because here (I'll ignore the first three lines since they have nothing to do with this):
func tableView(_ tableView: UITableView, viewForHeaderInSection section: Int) -> UIView? {
//guard let viewModel = presenter.headerViewModel(for: section) else { return nil }
//let dateSummaryView = DateSummaryView(frame: .zero)
//dateSummaryView.setup(with: viewModel)
let disruptionsViewController = DisruptionsInfoViewController()
return disruptionsViewController.view
// as soon as we return, disruptionsViewController is released
// and no code it contains will be executed
}
You created an instance of DisruptionsInfoViewController, pulled out its view, and then tossed away the controller code.
If you want to use this approach (rather odd, but we have to assume you have a logical reason to do this), you need to keep a reference to DisruptionsInfoViewController so its code can be used:
func tableView(_ tableView: UITableView, viewForHeaderInSection section: Int) -> UIView? {
let disruptionsViewController = DisruptionsInfoViewController()
// add disruptionsViewController as a child view controller
// this will "hold on to it" so its code can execute
addChild(disruptionsViewController)
disruptionsViewController.didMove(toParent: self)
return disruptionsViewController.view
}
Now, this is technically incorrect, as Apple's docs state:
Call the addChildViewController: method of your container view controller.
Add the child’s root view to your container’s view hierarchy.
Add any constraints for managing the size and position of the child’s root view.
Call the didMoveToParentViewController: method of the child view controller.
But, because we are returning the view for use as a section header view, we cannot perform 2. before calling didMove(toParent: self).
You didn't include in your post (or mention in your comments) how you're setting the Height of the section header, so, using:
func tableView(_ tableView: UITableView, heightForHeaderInSection section: Int) -> CGFloat {
return 150.0
}
We get this with your original code - section header view background color is blue, the "table view in header view" background color is green:
and we get this when using addChild():
Here is a complete example project: https://github.com/DonMag/Disrupt
While this will work, if you really want to embed a table view in another table view's section header(s), there are better ways to do it.