UITableView header dynamic height in run-time

Question

I know there are a lot of posts about it, but maybe in newest iOS there are some updates on this...

I think all of us had a task to create viewController that has a lot of content at the top, most of them are self-sizing, and at the very bottom it figures out that you need to show some tableView with many items...

The first solution that can be done is to use UIScrollView, and don't care about reusableCells at all.
The second is to use UITableView's headerView and adjust its height manually (or by calling systemLayoutSizeFittingSize:) each time when it is needed.
Maybe the third solution is to use UITableView and self-sized UIView separately, with having UIEdgeInsets on tableView. And depending on what object has higher "zIndex", it can bring problems with handling interactions...
The forth solution is to use whole content above the cell, like a separate cell. Not sure this is a good idea at all...

Question: Is there any new solution to this problem? I haven't dig into it for like 2 years... Maybe in new iOS there is something like reusableViews for UIScrollView... Of course, the goal is to have reusable cells, and header with using autolayout without necessity of updating its height manually...

Answer 1

I am guessing you are talking about section headers of table view here. If that is so you can absolutely use auto layout for section headers.

Use the below two code in viewDidLoad:

tableView.sectionHeaderHeight = UITableViewAutomaticDimension
tableView.estimatedSectionHeaderHeight = 36;

Now in viewForHeaderInSection: try the below code just to get an idea how things are working out. Change it according to your requirement.

func tableView(_ tableView: UITableView, viewForHeaderInSection section: Int) -> UIView? {
    let label: UILabel = {
       let lb = UILabel()
        lb.translatesAutoresizingMaskIntoConstraints = false
        lb.text = "HEADER \(section) with a loooooooooooooooonnngngngngngngngng texxxxxxxxxxxxxxxxt"
        lb.textColor = .black
        lb.backgroundColor = .yellow
        lb.numberOfLines = 0
        return lb
    }()

    let header: UIView = {
        let hd = UIView()
        hd.backgroundColor = .blue
        hd.addSubview(label)
        label.leadingAnchor.constraint(equalTo: hd.leadingAnchor, constant: 8).isActive = true
        label.topAnchor.constraint(equalTo: hd.topAnchor, constant: 8).isActive = true
        label.trailingAnchor.constraint(equalTo: hd.trailingAnchor, constant: -8).isActive = true
        label.bottomAnchor.constraint(equalTo: hd.bottomAnchor, constant: -8).isActive = true
        return hd
    }()
    return header
}

Answer 2

I'm using XCode 10.3 and this is my solution worked with your second solution using table header view.

First, you would create a separating view with xib file, for example with a label inside. And you apply the constraints for this label, top, left, bottom, right to the cell's container view. And set numberOfLines = 0.

Update your awakeFromNib() function inside your view class.

override func awakeFromNib() {
    super.awakeFromNib()
    ourLabel.translatesAutoresizingMaskIntoConstraints = false
}

Second, on your viewController, setup your tableView:

tableView.sectionHeaderHeight = UITableView.automaticDimension
tableView.estimatedSectionHeaderHeight = 64

Remember don't delegate this method:

func tableView(_ tableView: UITableView, heightForHeaderInSection section: Int) -> CGFloat

because we set the constraints of our view already.

Finally, you return it on the delegate method

func tableView(_ tableView: UITableView, viewForHeaderInSection section: Int) -> UIView?

the view for header.

let view = UINib(nibName: String(describing: SimpleHeaderTitleView.self), bundle: nil).instantiate(withOwner: nil, options: nil)[0] as! SimpleHeaderTitleView
 view.ourLabel.text = "Your longgggg text"
 return view

Done! Check it works.

Answer 3

I like the way it's done here:

• If you want to set your tableview header height dynamically based on it's content, just call self.tableView.layoutTableFooterView() right after you have set your headerView as TableViewHeader (so after self.tableView.tableHeaderView = view )

• If you need to update your tableview header height on runtime, also call self.tableView.layoutTableFooterView() right after you have updated the values of your tableview header.

(This obviously also works with tableviewFooters, though, is not to be used for sectionHeaders/Footers)

extension UITableView {

    //Variable-height UITableView tableHeaderView with autolayout
    func layoutTableHeaderView() {

        guard let headerView = self.tableHeaderView else { return }
        headerView.translatesAutoresizingMaskIntoConstraints = false

        let headerWidth = headerView.bounds.size.width
        let temporaryWidthConstraint = headerView.widthAnchor.constraint(equalToConstant: headerWidth)

        headerView.addConstraint(temporaryWidthConstraint)

        headerView.setNeedsLayout()
        headerView.layoutIfNeeded()

        let headerSize = headerView.systemLayoutSizeFitting(UILayoutFittingCompressedSize)
        let height = headerSize.height
        var frame = headerView.frame

        frame.size.height = height
        headerView.frame = frame

        self.tableHeaderView = headerView

        headerView.removeConstraint(temporaryWidthConstraint)
        headerView.translatesAutoresizingMaskIntoConstraints = true
    }

}

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