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

Question

I\'m been smashing my head against the wall with this for last 3 or 4 hours and I can\'t seem to figure it out. I have a UIViewController with a full screen UITableView insi

Answer 1

It is quite possible to use generic AutoLayout-based UIView with any AL inner subview structure as a tableHeaderView.

The only thing one needs is to set a simple tableFooterView before!

Let self.headerView is some constraint-based UIView.

- (void)viewDidLoad {

    ........................

    self.tableView.tableFooterView = [UIView new];

    [self.headerView layoutIfNeeded]; // to set initial size

    self.tableView.tableHeaderView = self.headerView;

    [self.tableView.leadingAnchor constraintEqualToAnchor:self.headerView.leadingAnchor].active = YES;
    [self.tableView.trailingAnchor constraintEqualToAnchor:self.headerView.trailingAnchor].active = YES;
    [self.tableView.topAnchor constraintEqualToAnchor:self.headerView.topAnchor].active = YES;

    // and the key constraint
    [self.tableFooterView.trailingAnchor constraintEqualToAnchor:self.headerView.trailingAnchor].active = YES;
}

If self.headerView changes height under UI rotation one have to implement

- (void)viewWillTransitionToSize:(CGSize)size withTransitionCoordinator:(id)coordinator {
    [super viewWillTransitionToSize:size withTransitionCoordinator:coordinator];

    [coordinator animateAlongsideTransition: ^(id context) {
        // needed to resize header height
        self.tableView.tableHeaderView = self.headerView;
    } completion: NULL];
}

One can use ObjC category for this purpose

@interface UITableView (AMHeaderView)
- (void)am_insertHeaderView:(UIView *)headerView;
@end

@implementation UITableView (AMHeaderView)

- (void)am_insertHeaderView:(UIView *)headerView {

    NSAssert(self.tableFooterView, @"Need to define tableFooterView first!");

    [headerView layoutIfNeeded];

    self.tableHeaderView = headerView;

    [self.leadingAnchor constraintEqualToAnchor:headerView.leadingAnchor].active = YES;
    [self.trailingAnchor constraintEqualToAnchor:headerView.trailingAnchor].active = YES;
    [self.topAnchor constraintEqualToAnchor:headerView.topAnchor].active = YES;

    [self.tableFooterView.trailingAnchor constraintEqualToAnchor:headerView.trailingAnchor].active = YES;
}
@end

And also Swift extension

extension UITableView {

    func am_insertHeaderView2(_ headerView: UIView) {

        assert(tableFooterView != nil, "Need to define tableFooterView first!")

        headerView.layoutIfNeeded()

        tableHeaderView = headerView

        leadingAnchor.constraint(equalTo: headerView.leadingAnchor).isActive = true
        trailingAnchor.constraint(equalTo: headerView.trailingAnchor).isActive = true
        topAnchor.constraint(equalTo: headerView.topAnchor).isActive = true

        tableFooterView?.trailingAnchor.constraint(equalTo: headerView.trailingAnchor).isActive = true
    }
}