Using Autolayout in a Tableheaderview

Is it possible to use AutoLayout with UITableView's tableHeaderView?

I asked and answered a similar question here. In summary, I add the header once and use it to find the required height. That height can then be applied to the header, and the header is set a second time to reflect the change.

- (void)viewDidLoad
{
    [super viewDidLoad];

    self.header = [[SCAMessageView alloc] init];
    self.header.titleLabel.text = @"Warning";
    self.header.subtitleLabel.text = @"This is a message with enough text to span multiple lines. This text is set at runtime and might be short or long.";

    //set the tableHeaderView so that the required height can be determined
    self.tableView.tableHeaderView = self.header;
    [self.header setNeedsLayout];
    [self.header layoutIfNeeded];
    CGFloat height = [self.header systemLayoutSizeFittingSize:UILayoutFittingCompressedSize].height;

    //update the header's frame and set it again
    CGRect headerFrame = self.header.frame;
    headerFrame.size.height = height;
    self.header.frame = headerFrame;
    self.tableView.tableHeaderView = self.header;
}

If you have multi-line labels, this also relies on the custom view setting the preferredMaxLayoutWidth of each label:

- (void)layoutSubviews
{
    [super layoutSubviews];

    self.titleLabel.preferredMaxLayoutWidth = CGRectGetWidth(self.titleLabel.frame);
    self.subtitleLabel.preferredMaxLayoutWidth = CGRectGetWidth(self.subtitleLabel.frame);
}

or perhaps more generally:

override func layoutSubviews() {
    super.layoutSubviews()  
    for view in subviews {
        guard let label = view as? UILabel where label.numberOfLines == 0 else { continue }
        label.preferredMaxLayoutWidth = CGRectGetWidth(label.frame)
    }
}

Update January 2015

Unfortunately this still seems necessary. Here is a swift version of the layout process:

tableView.tableHeaderView = header
header.setNeedsLayout()
header.layoutIfNeeded()
header.frame.size = header.systemLayoutSizeFittingSize(UILayoutFittingCompressedSize)
tableView.tableHeaderView = header

I've found it useful to move this into an extension on UITableView:

extension UITableView {
    //set the tableHeaderView so that the required height can be determined, update the header's frame and set it again
    func setAndLayoutTableHeaderView(header: UIView) {
        self.tableHeaderView = header
        self.tableHeaderView?.translatesAutoresizingMaskIntoConstraints = false
        NSLayoutConstraint.activate([
            header.widthAnchor.constraint(equalTo: self.widthAnchor)
        ])
        header.setNeedsLayout()
        header.layoutIfNeeded()
        header.frame.size =  header.systemLayoutSizeFitting(UIView.layoutFittingCompressedSize)
        self.tableHeaderView = header
    }
}

Usage:

let header = SCAMessageView()
header.titleLabel.text = "Warning"
header.subtitleLabel.text = "Warning message here."
tableView.setAndLayoutTableHeaderView(header)

Using autolayout in a tableHeaderView

My own best answer so far involves setting the tableHeaderView once and forcing a layout pass. This allows a required size to be measured, which I then use to set the frame of the header. And, as is common with tableHeaderViews, I have to again set it a second time to apply the change.

- (void)viewDidLoad
{
    [super viewDidLoad];

    self.header = [[SCAMessageView alloc] init];
    self.header.titleLabel.text = @"Warning";
    self.header.subtitleLabel.text = @"This is a message with enough text to span multiple lines. This text is set at runtime and might be short or long.";

    //set the tableHeaderView so that the required height can be determined
    self.tableView.tableHeaderView = self.header;
    [self.header setNeedsLayout];
    [self.header layoutIfNeeded];
    CGFloat height = [self.header systemLayoutSizeFittingSize:UILayoutFittingCompressedSize].height;

    //update the header's frame and set it again
    CGRect headerFrame = self.header.frame;
    headerFrame.size.height = height;
    self.header.frame = headerFrame;
    self.tableView.tableHeaderView = self.header;
}

For multiline labels, this also relies on the custom view (the message view in this case) setting the preferredMaxLayoutWidth of each:

- (void)layoutSubviews
{
    [super layoutSubviews];

    self.titleLabel.preferredMaxLayoutWidth = CGRectGetWidth(self.titleLabel.frame);
    self.subtitleLabel.preferredMaxLayoutWidth = CGRectGetWidth(self.subtitleLabel.frame);
}

Update January 2015

Unfortunately this still seems necessary. Here is a swift version of the layout process:

tableView.tableHeaderView = header
header.setNeedsLayout()
header.layoutIfNeeded()
let height = header.systemLayoutSizeFittingSize(UILayoutFittingCompressedSize).height
var frame = header.frame
frame.size.height = height
header.frame = frame
tableView.tableHeaderView = header

I've found it useful to move this into an extension on UITableView:

extension UITableView {
    //set the tableHeaderView so that the required height can be determined, update the header's frame and set it again
    func setAndLayoutTableHeaderView(header: UIView) {
        self.tableHeaderView = header
        header.setNeedsLayout()
        header.layoutIfNeeded()
        let height = header.systemLayoutSizeFittingSize(UILayoutFittingCompressedSize).height
        var frame = header.frame
        frame.size.height = height
        header.frame = frame
        self.tableHeaderView = header
    }
}

Usage:

let header = SCAMessageView()
header.titleLabel.text = "Warning"
header.subtitleLabel.text = "Warning message here."
tableView.setAndLayoutTableHeaderView(header)

tableHeaderView with Autolayout not working correctly

In order to make it work you'll need some magic or migrate away from table header view. I've already answered on a similar question here. The trick is to magically reset tableHeaderView after evaluating it's height via autolayout. I've created sample project for that: TableHeaderView+Autolayout.

How do you install a tableHeaderView on a UITableView?

While I agree it seems like there would be a more straight-forward way of implementing an auto-height-sizing tableHeaderView, a common approach is to use auto-layout and an extension like this:

extension UITableView {
    func sizeHeaderToFit() {
        guard let headerView = tableHeaderView else { return }
        
        let newHeight = headerView.systemLayoutSizeFitting(CGSize(width: frame.width, height: .greatestFiniteMagnitude), withHorizontalFittingPriority: .required, verticalFittingPriority: .defaultLow)
        var frame = headerView.frame
        
        // avoids infinite loop!
        if newHeight.height != frame.height {
            frame.size.height = newHeight.height
            headerView.frame = frame
            tableHeaderView = headerView
        }
    }
}

We call that from within viewDidLayoutSubviews():

override func viewDidLayoutSubviews() {
    super.viewDidLayoutSubviews()
    tableView.sizeHeaderToFit()
}

Here is a complete example, which should come pretty close to your layout:

class TestViewController: UIViewController {
    
    let tableView = UITableView()
    
    override func viewDidLoad() {
        super.viewDidLoad()
        
        tableView.translatesAutoresizingMaskIntoConstraints = false
        
        view.addSubview(tableView)
        
        let g = view.safeAreaLayoutGuide
        NSLayoutConstraint.activate([
            tableView.topAnchor.constraint(equalTo: g.topAnchor),
            tableView.leadingAnchor.constraint(equalTo: g.leadingAnchor),
            tableView.trailingAnchor.constraint(equalTo: g.trailingAnchor),
            tableView.bottomAnchor.constraint(equalTo: g.bottomAnchor),
        ])
        
        tableView.register(UITableViewCell.self, forCellReuseIdentifier: "cell")
        tableView.dataSource = self
        tableView.delegate = self
        
        let hView = EventDetailTableHeaderView(titleText: "Street Dance Championships", subTitleText: "4 June 2019  |  8:30 AM to 5:30 PM  |  Sports Wales National Centre  |  Cardiff")
        tableView.tableHeaderView = hView
    }
    
    override func viewDidLayoutSubviews() {
        super.viewDidLayoutSubviews()
        tableView.sizeHeaderToFit()
    }
}

extension TestViewController: UITableViewDelegate, UITableViewDataSource {
    func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        return 30
    }
    func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
        let c = tableView.dequeueReusableCell(withIdentifier: "cell", for: indexPath)
        c.textLabel?.text = "\(indexPath)"
        return c
    }
}

extension UITableView {
    func sizeHeaderToFit() {
        guard let headerView = tableHeaderView else { return }
        
        let newHeight = headerView.systemLayoutSizeFitting(CGSize(width: frame.width, height: .greatestFiniteMagnitude), withHorizontalFittingPriority: .required, verticalFittingPriority: .defaultLow)
        var frame = headerView.frame
        
        // avoids infinite loop!
        if newHeight.height != frame.height {
            frame.size.height = newHeight.height
            headerView.frame = frame
            tableHeaderView = headerView
        }
    }
}

class TitleContainerView: UIView {

    private static let font: UIFont = .systemFont(ofSize: 32, weight: .heavy)
    
    let label: UILabel = {
        let v = UILabel()
        v.numberOfLines = 0
        v.textColor = UIColor(red: 0.044, green: 0.371, blue: 0.655, alpha: 1.0)
        v.font = TitleContainerView.font
        return v
    }()

    convenience init(text: String) {
        self.init(frame: .zero)
        label.text = text
    }
    override init(frame: CGRect) {
        super.init(frame: frame)
        commonInit()
    }
    required init?(coder: NSCoder) {
        super.init(coder: coder)
        commonInit()
    }
    func commonInit() -> Void {
        backgroundColor = UIColor(red: 0.93, green: 0.94, blue: 0.95, alpha: 1.0)
        label.translatesAutoresizingMaskIntoConstraints = false
        addSubview(label)
        NSLayoutConstraint.activate([
            label.topAnchor.constraint(equalTo: topAnchor, constant: 8.0),
            label.leadingAnchor.constraint(equalTo: leadingAnchor, constant: 8.0),
            label.trailingAnchor.constraint(equalTo: trailingAnchor, constant: -8.0),
            label.bottomAnchor.constraint(equalTo: bottomAnchor, constant: -8.0),
        ])
    }

}
class SubtitleContainerView: UIView {
    
    private static let font: UIFont = .systemFont(ofSize: 20, weight: .bold)
    
    let label: UILabel = {
        let v = UILabel()
        v.numberOfLines = 0
        v.textColor = .white
        v.font = SubtitleContainerView.font
        return v
    }()
    
    convenience init(text: String) {
        self.init(frame: .zero)
        label.text = text
    }
    override init(frame: CGRect) {
        super.init(frame: frame)
        commonInit()
    }
    required init?(coder: NSCoder) {
        super.init(coder: coder)
        commonInit()
    }
    func commonInit() -> Void {
        backgroundColor = UIColor(red: 0.044, green: 0.371, blue: 0.655, alpha: 1.0)
        label.translatesAutoresizingMaskIntoConstraints = false
        addSubview(label)
        NSLayoutConstraint.activate([
            label.topAnchor.constraint(equalTo: topAnchor, constant: 8.0),
            label.leadingAnchor.constraint(equalTo: leadingAnchor, constant: 8.0),
            label.trailingAnchor.constraint(equalTo: trailingAnchor, constant: -8.0),
            label.bottomAnchor.constraint(equalTo: bottomAnchor, constant: -8.0),
        ])
    }
}

class EventDetailTableHeaderView: UIView {
    
    var titleView: TitleContainerView!
    var subTitleView: SubtitleContainerView!
    
    convenience init(titleText: String, subTitleText: String) {
        self.init(frame: .zero)
        titleView = TitleContainerView(text: titleText)
        subTitleView = SubtitleContainerView(text: subTitleText)
        commonInit()
    }
    
    func commonInit() -> Void {
        titleView.translatesAutoresizingMaskIntoConstraints = false
        subTitleView.translatesAutoresizingMaskIntoConstraints = false
        addSubview(titleView)
        addSubview(subTitleView)
        
        // this avoids auto-layout complaints
        let titleViewTrailingConstraint = titleView.trailingAnchor.constraint(equalTo: trailingAnchor, constant: 0.0)
        titleViewTrailingConstraint.priority = UILayoutPriority(rawValue: 999)
        let subTitleViewBottomConstraint = subTitleView.bottomAnchor.constraint(equalTo: bottomAnchor, constant: 0.0)
        subTitleViewBottomConstraint.priority = UILayoutPriority(rawValue: 999)
        
        NSLayoutConstraint.activate([
            titleView.topAnchor.constraint(equalTo: topAnchor, constant: 0.0),
            titleView.leadingAnchor.constraint(equalTo: leadingAnchor, constant: 0.0),
            
            titleViewTrailingConstraint,
            
            subTitleView.topAnchor.constraint(equalTo: titleView.bottomAnchor, constant: 0.0),
            subTitleView.leadingAnchor.constraint(equalTo: titleView.leadingAnchor, constant: 0.0),
            subTitleView.trailingAnchor.constraint(equalTo: titleView.trailingAnchor, constant: 0.0),
            
            subTitleViewBottomConstraint,
        ])
        
    }

}

and the output looks like this:

---

Edit -- same output, but using auto-layout only for adding the tableView to the main view.

Class names prefixed with RM_ (for Resizing Mask):

class RM_TestViewController: UIViewController {
    
    let tableView = UITableView()
    
    override func viewDidLoad() {
        super.viewDidLoad()
        
        tableView.translatesAutoresizingMaskIntoConstraints = false
        
        view.addSubview(tableView)
        
        let g = view.safeAreaLayoutGuide
        NSLayoutConstraint.activate([
            tableView.topAnchor.constraint(equalTo: g.topAnchor),
            tableView.leadingAnchor.constraint(equalTo: g.leadingAnchor),
            tableView.trailingAnchor.constraint(equalTo: g.trailingAnchor),
            tableView.bottomAnchor.constraint(equalTo: g.bottomAnchor),
        ])
        
        tableView.register(UITableViewCell.self, forCellReuseIdentifier: "cell")
        tableView.dataSource = self
        tableView.delegate = self
        
        let hView = RM_EventDetailTableHeaderView(titleText: "Street Dance Championships", subTitleText: "4 June 2019  |  8:30 AM to 5:30 PM  |  Sports Wales National Centre  |  Cardiff")
        tableView.tableHeaderView = hView
    }
    
    override func viewDidLayoutSubviews() {
        super.viewDidLayoutSubviews()
        tableView.rm_sizeHeaderToFit()
    }
}

extension RM_TestViewController: UITableViewDelegate, UITableViewDataSource {
    func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        return 30
    }
    func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
        let c = tableView.dequeueReusableCell(withIdentifier: "cell", for: indexPath)
        c.textLabel?.text = "\(indexPath)"
        return c
    }
}

extension UITableView {
    func rm_sizeHeaderToFit() {
        guard let headerView = tableHeaderView as? RM_EventDetailTableHeaderView else { return }
        
        headerView.setNeedsLayout()
        headerView.layoutIfNeeded()
        
        // avoids infinite loop!
        if headerView.myHeight != headerView.frame.height {
            headerView.frame.size.height = headerView.myHeight
            tableHeaderView = headerView
        }
    }
}

class RM_TitleContainerView: UIView {
    
    private static let font: UIFont = .systemFont(ofSize: 32, weight: .heavy)
    
    let label: UILabel = {
        let v = UILabel()
        v.numberOfLines = 0
        v.textColor = UIColor(red: 0.044, green: 0.371, blue: 0.655, alpha: 1.0)
        v.font = RM_TitleContainerView.font
        // during dev, so we can see the label frame
        //v.backgroundColor = .green
        return v
    }()
    
    convenience init(text: String) {
        self.init(frame: .zero)
        label.text = text
    }
    override init(frame: CGRect) {
        super.init(frame: frame)
        commonInit()
    }
    required init?(coder: NSCoder) {
        super.init(coder: coder)
        commonInit()
    }
    func commonInit() -> Void {
        backgroundColor = UIColor(red: 0.93, green: 0.94, blue: 0.95, alpha: 1.0)
        addSubview(label)
        label.frame.origin = CGPoint(x: 8, y: 8)
    }
    
    override func layoutSubviews() {
        super.layoutSubviews()
        label.frame.size.width = bounds.width - 16
        let sz = label.systemLayoutSizeFitting(CGSize(width: label.frame.width, height: .greatestFiniteMagnitude), withHorizontalFittingPriority: .required, verticalFittingPriority: .defaultLow)
        label.frame.size.height = sz.height
    }

    var myHeight: CGFloat {
        get {
            return label.frame.height + 16.0
        }
    }
}
class RM_SubtitleContainerView: UIView {
    
    private static let font: UIFont = .systemFont(ofSize: 20, weight: .bold)
    
    let label: UILabel = {
        let v = UILabel()
        v.numberOfLines = 0
        v.textColor = .white
        v.font = RM_SubtitleContainerView.font
        // during dev, so we can see the label frame
        //v.backgroundColor = .systemYellow
        return v
    }()
    
    convenience init(text: String) {
        self.init(frame: .zero)
        label.text = text
    }
    override init(frame: CGRect) {
        super.init(frame: frame)
        commonInit()
    }
    required init?(coder: NSCoder) {
        super.init(coder: coder)
        commonInit()
    }
    func commonInit() -> Void {
        backgroundColor = UIColor(red: 0.044, green: 0.371, blue: 0.655, alpha: 1.0)
        addSubview(label)
        label.frame.origin = CGPoint(x: 8, y: 8)
    }
    
    override func layoutSubviews() {
        super.layoutSubviews()
        label.frame.size.width = bounds.width - 16
        let sz = label.systemLayoutSizeFitting(CGSize(width: label.frame.width, height: .greatestFiniteMagnitude), withHorizontalFittingPriority: .required, verticalFittingPriority: .defaultLow)
        label.frame.size.height = sz.height
    }
    
    var myHeight: CGFloat {
        get {
            return label.frame.height + 16.0
        }
    }
}

class RM_EventDetailTableHeaderView: UIView {
    
    var titleView: RM_TitleContainerView!
    var subTitleView: RM_SubtitleContainerView!
    
    convenience init(titleText: String, subTitleText: String) {
        self.init(frame: .zero)
        titleView = RM_TitleContainerView(text: titleText)
        subTitleView = RM_SubtitleContainerView(text: subTitleText)
        commonInit()
    }
    
    func commonInit() -> Void {
        addSubview(titleView)
        addSubview(subTitleView)
        
        // initial height doesn't matter
        titleView.frame = CGRect(x: 0, y: 0, width: self.frame.width, height: 8)
        subTitleView.frame = CGRect(x: 0, y: 0, width: self.frame.width, height: 8)
        
        titleView.autoresizingMask = [.flexibleWidth]
        subTitleView.autoresizingMask = [.flexibleWidth]
    }
    
    override func layoutSubviews() {
        super.layoutSubviews()
        
        // force subviews to update
        titleView.setNeedsLayout()
        subTitleView.setNeedsLayout()
        titleView.layoutIfNeeded()
        subTitleView.layoutIfNeeded()
        
        // get subview heights
        titleView.frame.size.height = titleView.myHeight
        subTitleView.frame.origin.y = titleView.frame.maxY
        subTitleView.frame.size.height = subTitleView.myHeight
    }
    
    var myHeight: CGFloat {
        get {
            return subTitleView.frame.maxY
        }
    }
}

UITableView tableHeaderView using autolayout height too small

Answering my own question here:

There are 2 steps that seem to get this to work. The first is in ViewDidLoad, and the second is in viewDidLayoutSubviews:

var headerView: UIView!

override func viewDidLoad() {
    super.viewDidLoad()

    if let currentTableHeaderView = self.tableView.tableHeaderView {
        currentTableHeaderView.removeFromSuperview()
    }
    // Setting the table header view with a height of 0.01 fixes a bug that adds a gap between the
    // tableHeaderView (once added) and the top row. See: http://stackoverflow.com/a/18938763/657676
    self.tableView.tableHeaderView = UIView(frame: CGRectMake(0, 0, CGRectGetWidth(self.tableView.frame), 0.01))
    self.headerView = AboutTableViewHeaderView(frame: CGRectZero)
}

override func viewDidLayoutSubviews() {
    super.viewDidLayoutSubviews()
    if let tableHeaderView = self.headerView {
        var frame = CGRectZero
        frame.size.width = self.tableView.bounds.size.width
        frame.size.height = tableHeaderView.systemLayoutSizeFittingSize(UILayoutFittingCompressedSize).height
        if self.tableView.tableHeaderView == nil || !CGRectEqualToRect(frame, tableHeaderView.frame) {
            tableHeaderView.frame = frame
            tableHeaderView.layoutIfNeeded()
            self.tableView.tableHeaderView = tableHeaderView
        }
    }
}

Hopefully that all makes sense. The viewDidLayoutSubview code is via http://osdir.com/ml/general/2014-06/msg19399.html

Auto Layout for tableHeaderView

If you make a instance variable for the NSLayoutConstraint and set it like so:

headerViewHeightConstraint = [NSLayoutConstraint constraintWithItem:headerView
                                                          attribute:NSLayoutAttributeHeight
                                                          relatedBy:NSLayoutRelationEqual
                                                             toItem:nil
                                                          attribute:NSLayoutAttributeNotAnAttribute
                                                         multiplier:1.0f
                                                           constant:otherView.frame.size.height];

You can resize it by:

headerViewHeightConstraint.constant = 1000.0f;
[headerView updateConstraintsIfNeeded];

---

P.S: keep in mind that addConstraints: is not the same thing as addConstraint:.

addConstraints is used in conjunction with an array of constraints or [NSLayoutConstraints constraintsWithVisualFormat:...]

addConstraint: is used in conjunction with a single constraint which is the example above.

If you're overriding layoutSubviews: call [super layoutSubviews] in its very first line. That forces the view and its subviews to layout themselves so you can access their frame details etc.

How do I set the height of tableHeaderView (UITableView) with autolayout?

You need to use the UIView systemLayoutSizeFittingSize: method to obtain the minimum bounding size of your header view.

I provide further discussion on using this API in this Q/A:

How to resize superview to fit all subviews with autolayout?

Can't center views in tableHeaderView with auto layout and storyboards

Make sure that your UITableView has the leading, trailing, bottom, top constraints set up against its superview.

---

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