If you use cell registrations instead of supplementary registrations, the keyboard doesn't dismiss for any reason and you can also get rid of the dispatch blocks:
import UIKit
class ViewController: UIViewController {
let words = ["foo", "bar"]
var filteredWords = ["foo", "bar"] {
didSet {
dataSource.apply(self.snapshot)
}
}
var collectionView: UICollectionView!
var dataSource: UICollectionViewDiffableDataSource<String, String>!
var snapshot: NSDiffableDataSourceSnapshot<String, String> {
var snapshot = NSDiffableDataSourceSnapshot<String, String>()
snapshot.appendSections(["main"])
snapshot.appendItems(["search bar id"])
snapshot.appendItems(filteredWords)
return snapshot
}
override func viewDidLoad() {
super.viewDidLoad()
navigationItem.rightBarButtonItem = .init(title: "Apply", style: .plain, target: self, action: #selector(apply))
configureHierarchy()
configureDataSource()
}
@objc func apply() {
dataSource.apply(self.snapshot)
}
func configureHierarchy() {
collectionView = .init(frame: .zero, collectionViewLayout: createLayout())
view.addSubview(collectionView)
collectionView.frame = view.bounds
collectionView.autoresizingMask = [.flexibleWidth, .flexibleHeight]
}
func createLayout() -> UICollectionViewLayout {
UICollectionViewCompositionalLayout { section, layoutEnvironment in
var config = UICollectionLayoutListConfiguration(appearance: .insetGrouped)
config.headerMode = .firstItemInSection
return NSCollectionLayoutSection.list(using: config, layoutEnvironment: layoutEnvironment)
}
}
func configureDataSource() {
let cellRegistration = UICollectionView.CellRegistration<UICollectionViewListCell, String> { _, _, _ in }
let searchBarCellRegistration = UICollectionView.CellRegistration<SearchBarCell, String>{ cell, indexPath, itemIdentifier in
cell.searchBar.delegate = self
}
dataSource = .init(collectionView: collectionView) { collectionView, indexPath, itemIdentifier in
if indexPath.row == 0 {
collectionView.dequeueConfiguredReusableCell(using: searchBarCellRegistration, for: indexPath, item: itemIdentifier)
} else {
collectionView.dequeueConfiguredReusableCell(using: cellRegistration, for: indexPath, item: itemIdentifier)
}
}
dataSource.apply(self.snapshot, animatingDifferences: false)
}
}
extension ViewController: UISearchBarDelegate {
func searchBar(_ searchBar: UISearchBar, textDidChange searchText: String) {
filteredWords = words.filter { $0.hasPrefix(searchText) }
}
func searchBarTextDidEndEditing(_ searchBar: UISearchBar) {
filteredWords = words
}
}
class SearchBarCell: UICollectionViewListCell {
let searchBar = UISearchBar()
override init(frame: CGRect) {
super.init(frame: frame)
contentView.addSubview(searchBar)
searchBar.pinToSuperview()
}
required init?(coder: NSCoder) {
fatalError("init(coder:) has not been implemented")
}
}
extension UIView {
func pin(
to object: CanBePinnedTo,
top: CGFloat = 0,
bottom: CGFloat = 0,
leading: CGFloat = 0,
trailing: CGFloat = 0
) {
self.translatesAutoresizingMaskIntoConstraints = false
NSLayoutConstraint.activate([
self.topAnchor.constraint(equalTo: object.topAnchor, constant: top),
self.bottomAnchor.constraint(equalTo: object.bottomAnchor, constant: bottom),
self.leadingAnchor.constraint(equalTo: object.leadingAnchor, constant: leading),
self.trailingAnchor.constraint(equalTo: object.trailingAnchor, constant: trailing),
])
}
func pinToSuperview(
top: CGFloat = 0,
bottom: CGFloat = 0,
leading: CGFloat = 0,
trailing: CGFloat = 0,
file: StaticString = #file,
line: UInt = #line
) {
guard let superview = self.superview else {
print(">> \(#function) failed in file: \(String.localFilePath(from: file)), at line: \(line): could not find \(Self.self).superView.")
return
}
self.pin(to: superview, top: top, bottom: bottom, leading: leading, trailing: trailing)
}
func pinToSuperview(constant c: CGFloat = 0, file: StaticString = #file, line: UInt = #line) {
self.pinToSuperview(top: c, bottom: -c, leading: c, trailing: -c, file: file, line: line)
}
}
@MainActor
protocol CanBePinnedTo {
var topAnchor: NSLayoutYAxisAnchor { get }
var bottomAnchor: NSLayoutYAxisAnchor { get }
var leadingAnchor: NSLayoutXAxisAnchor { get }
var trailingAnchor: NSLayoutXAxisAnchor { get }
}
extension UIView: CanBePinnedTo { }
extension UILayoutGuide: CanBePinnedTo { }
extension String {
static func localFilePath(from fullFilePath: StaticString = #file) -> Self {
URL(fileURLWithPath: "\(fullFilePath)").lastPathComponent
}
}
Basically don't use supplementary views unless absolutely necessary: it also seems that there's no declarative way to update them without losing animations (Apple's guided project "Modern Collection Views" doesn't seem to provide a solution, nor do these posts: https://stackoverflow.com/questions/78311570/how-do-i-update-a-collection-view-supplementary-view-without-giving-up-on-animat, https://forums.developer.apple.com/forums/thread/749847).
