Adjust position of bar button item when using large titles with iOS 11

To solve my own problem, I just added a button as a subview of the navbar and set the right and bottom constraints to the navbar. The button will now move up and down when the navbar changes size. However, this requires the button to be removed in any view controllers that you show segue from this view controller. Thus, I added a tag of 1 to the button and removed it from its superview from the other view controller. This is the easiest way to solve it, and I found it the easiest method.

To setup the right button:

func setupNavBar() {    self.title = "Home"    self.navigationController?.navigationBar.prefersLargeTitles = true    self.navigationController?.navigationBar.isTranslucent = false    let searchController = UISearchController(searchResultsController: nil)    self.navigationItem.searchController = searchController    let rightButton = UIButton()    rightButton.setTitle("Right Button", for: .normal)    rightButton.setTitleColor(.purple, for: .normal)    rightButton.addTarget(self, action: #selector(rightButtonTapped(_:)), for: .touchUpInside)    navigationController?.navigationBar.addSubview(rightButton)    rightButton.tag = 1    rightButton.frame = CGRect(x: self.view.frame.width, y: 0, width: 120, height: 20)    let targetView = self.navigationController?.navigationBar    let trailingContraint = NSLayoutConstraint(item: rightButton, attribute:        .trailingMargin, relatedBy: .equal, toItem: targetView,                         attribute: .trailingMargin, multiplier: 1.0, constant: -16)    let bottomConstraint = NSLayoutConstraint(item: rightButton, attribute: .bottom, relatedBy: .equal,                                    toItem: targetView, attribute: .bottom, multiplier: 1.0, constant: -6)    rightButton.translatesAutoresizingMaskIntoConstraints = false    NSLayoutConstraint.activate([trailingContraint, bottomConstraint])}

To remove it from any show segued view controllers:

func removeRightButton(){    guard let subviews = self.navigationController?.navigationBar.subviews else{return}    for view in subviews{        if view.tag != 0{            view.removeFromSuperview()        }    }} 

Both functions are called in the viewWillAppear function

I made some digging and I finally came up with quite the same behavior as in the Messages app (meaning the button goes under the navigationBar and not above).The only missing part is the nice animation/blur thing which happens when the UIBarButtonItem appears…

Fair Warning : my current solution is using a private class (named _UINavigationBarLargeTitleView) and Apple could reject your app for this very reason…

// Make sure you have a `navigationBar`guard let navigationBar = navigationController?.navigationBar else {    return}// Make sure you get the correct class from the string, the class itself is not exposed…guard let UINavigationBarLargeTitleView = NSClassFromString("_UINavigationBarLargeTitleView") else {    return}// Then, you need to find the subview of type `_UINavigationBarLargeTitleView` :navigationBar.subviews.forEach { subview in    if subview.isKind(of: UINavigationBarLargeTitleView.self) {        // If you have it, add whatever button you want (some example below)        subview.addSubview(largeTitleViewRightBarButton)        // Constrain it as you want        NSLayoutConstraint.activate([            largeTitleViewRightBarButton.bottomAnchor.constraint(equalTo: subview.bottomAnchor, constant: -10),            largeTitleViewRightBarButton.trailingAnchor.constraint(                equalTo: subview.trailingAnchor,                constant: -view.directionalLayoutMargins.trailing            )        ])    }}// Finally, the magic happens with one scrollView delegate method :override func scrollViewDidScroll(_ scrollView: UIScrollView) {    if scrollView.contentOffset.y >= -103 { // Moving up        navigationItem.rightBarButtonItem = rightBarButtonItem    } else { // Moving down        navigationItem.rightBarButtonItem = nil    }}

Here is how I made my buttons :

private(set) lazy var image: UIImage? = {    let config = UIImage.SymbolConfiguration(pointSize: 28, weight: .semibold, scale: .default)    let image = UIImage(systemName: "magnifyingglass.circle.fill", withConfiguration: config)    return image}()private(set) lazy var largeTitleViewRightBarButton: UIButton = {    let button = UIButton(type: .custom)    button.translatesAutoresizingMaskIntoConstraints = false    button.imageView?.tintColor = R.color.appDodgerBlue()    button.setImage(image, for: .normal)    button.addTarget(presenter, action: #selector(presenter.onSearchRequested), for: .touchUpInside)    return button}()private(set) lazy var rightBarButtonItem: UIBarButtonItem = {    let barButtonItem = UIBarButtonItem(        image: image,        style: .plain,        target: presenter,        action: #selector(presenter.onSearchRequested)    )    return barButtonItem}()

Demo

What you want to do is set the title position adjustments of the BarButtonItem. Add the following line to the viewWillAppear func. Play with the vertical and horizontal value to get the layout of ur liking.

navigationItem.rightBarButtonItem?.setTitlePositionAdjustment(.init(horizontal: 10, vertical: 20), for: UIBarMetrics.default)

https://developer.apple.com/documentation/uikit/uibarbuttonitem/1617149-settitlepositionadjustment