UITableViewController+AutoLayoutHeaderView.swift

Autolayout TableView header

//
//  ViewController.swift
//  NaceApp
//
//  Created by Tobias Haeberle on 14.12.18.
//

import UIKit

class ViewController: UITableViewController {

    override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view, typically from a nib.
        
        self.updateLabelText()
        
    }

    @IBOutlet weak var headerView: UIView!
    @IBOutlet weak var label: UILabel!
    
    
    func updateLabelText() {
        let labelText = (0..<Int.random(in: 1..<50)).reduce(String(), { str, i in  return str + " my label " })
        
        self.label.text = labelText
        
        let size = self.headerView.systemLayoutSizeFitting(CGSize(width: self.tableView.frame.width, height: .greatestFiniteMagnitude), withHorizontalFittingPriority: .required, verticalFittingPriority: .defaultLow)
        
        self.headerView.bounds.size = size
        self.tableView.tableHeaderView = self.headerView
        
//        self.tableView.setNeedsLayout()
//        self.tableView.layoutIfNeeded()
        
        
        DispatchQueue.main.asyncAfter(deadline: .now() + 1, execute: {
            self.updateLabelText()
        })
    }
    
    
}