Adjust position of bar button item when using large titles with iOS 11
If anyone is still looking how to do this in SwiftUI. I made a package named NavigationBarLargeTitleItems to deal with this. It mimics the behavior you see in the AppStore and Messages-app.
In this example you will see a profile icon but you can also use text such as the Create Recipe-button. If you like to make it appear as a standard navigation bar item as soon as you scroll you need the GeometryReader for that. If you like an example please let me know.
Please note to be able to accomplish this behavior we need to add to the '_UINavigationBarLargeTitleView' which is a private class and therefor might get your app rejected when submitting to the App Store.
I'm also including the full relevant source code here for those who dislike links or just want to copy/paste.
Extension:
// Copyright © 2020 Mark van Wijnen
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the “Software”), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED “AS IS”, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
// SOFTWARE.
import SwiftUI
public extension View {
func navigationBarLargeTitleItems<L>(trailing: L) -> some View where L : View {
overlay(NavigationBarLargeTitleItems(trailing: trailing).frame(width: 0, height: 0))
}
}
fileprivate struct NavigationBarLargeTitleItems<L : View>: UIViewControllerRepresentable {
typealias UIViewControllerType = Wrapper
private let trailingItems: L
init(trailing: L) {
self.trailingItems = trailing
}
func makeUIViewController(context: Context) -> Wrapper {
Wrapper(representable: self)
}
func updateUIViewController(_ uiViewController: Wrapper, context: Context) {
}
class Wrapper: UIViewController {
private let representable: NavigationBarLargeTitleItems?
init(representable: NavigationBarLargeTitleItems) {
self.representable = representable
super.init(nibName: nil, bundle: nil)
}
required init?(coder: NSCoder) {
self.representable = nil
super.init(coder: coder)
}
override func viewWillAppear(_ animated: Bool) {
guard let representable = self.representable else { return }
guard let navigationBar = self.navigationController?.navigationBar else { return }
guard let UINavigationBarLargeTitleView = NSClassFromString("_UINavigationBarLargeTitleView") else { return }
navigationBar.subviews.forEach { subview in
if subview.isKind(of: UINavigationBarLargeTitleView.self) {
let controller = UIHostingController(rootView: representable.trailingItems)
controller.view.translatesAutoresizingMaskIntoConstraints = false
subview.addSubview(controller.view)
NSLayoutConstraint.activate([
controller.view.bottomAnchor.constraint(
equalTo: subview.bottomAnchor,
constant: -15
),
controller.view.trailingAnchor.constraint(
equalTo: subview.trailingAnchor,
constant: -view.directionalLayoutMargins.trailing
)
])
}
}
}
}
}
Usage:
import SwiftUI
import NavigationBarLargeTitleItems
struct ContentView: View {
var body: some View {
NavigationView {
List {
ForEach(1..<50) { index in
Text("Sample Row \(String(index))")
}
}
.navigationTitle("Navigation")
.navigationBarLargeTitleItems(trailing: ProfileIcon())
}
}
}
struct ContentView_Previews: PreviewProvider {
static var previews: some View {
ContentView()
}
}
struct ProfileIcon: View {
var body: some View{
Button(action: {
print("Profile button was tapped")
}) {
Image(systemName: "person.circle.fill")
.resizable()
.aspectRatio(contentMode: .fit)
.foregroundColor(.red)
.frame(width: 36, height: 36)
}
.offset(x: -20, y: 5)
}
}
Preview
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
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