SwiftUI SearchBar problem with NavigationLink - swiftui

Question

I've a problem in SwiftUI with the searchBar appear.
There's a delay on its appear when I use NavigationLink. I saw that the problem appears only with NavigationLinks, if I use a conditional overlay or others "handmade" way to move between Views the problem doesn't appear. You know what I could do to fix the problem?
Here's my views code:
import SwiftUI
struct ContentView: View {
#State var searchText = ""
var body: some View {
NavigationView{
NavigationLink(destination: ContentView2()){
Text("Go to Sub View")
}
.navigationBarTitle("Main View")
.add(SearchBar(text: self.$searchText, hide: true, placeholder: "Search", cancelButton: true, autocapitalization: .sentences))
}
}
}
struct ContentView2 : View {
#State var searchText = ""
var body: some View {
Text("Hello, world!")
.navigationBarTitle("Sub View")
.add(SearchBar(text: self.$searchText, hide: true, placeholder: "Search", cancelButton: true, autocapitalization: .sentences))
}
}
My SearchBar code
import SwiftUI
class SearchBar: NSObject, ObservableObject {
let searchController: UISearchController = UISearchController(searchResultsController: nil)
#Binding var text: String
let hide : Bool
let placeholder : String
let cancelButton : Bool
let autocapitalization : UITextAutocapitalizationType
init(text: Binding<String>, hide: Bool, placeholder: String, cancelButton: Bool, autocapitalization: UITextAutocapitalizationType) {
self._text = text
self.hide = hide
self.placeholder = placeholder
self.cancelButton = cancelButton
self.autocapitalization = autocapitalization
super.init()
self.searchController.obscuresBackgroundDuringPresentation = false
self.searchController.searchResultsUpdater = self
self.searchController.hidesNavigationBarDuringPresentation = hide
self.searchController.automaticallyShowsCancelButton = cancelButton
self.searchController.searchBar.placeholder = placeholder
self.searchController.searchBar.autocapitalizationType = autocapitalization
}
}
extension SearchBar: UISearchResultsUpdating {
func updateSearchResults(for searchController: UISearchController) {
// Publish search bar text changes.
if let searchBarText = searchController.searchBar.text {
self.text = searchBarText
}
}
}
struct SearchBarModifier: ViewModifier {
let searchBar: SearchBar
func body(content: Content) -> some View {
content
.overlay(
ViewControllerResolver { viewController in
viewController.navigationItem.searchController = self.searchBar.searchController
}
.frame(width: 0, height: 0)
)
}
}
extension View {
func add(_ searchBar: SearchBar) -> some View {
return self.modifier(SearchBarModifier(searchBar: searchBar))
}
}
My ViewController code
import SwiftUI
final class ViewControllerResolver: UIViewControllerRepresentable {
let onResolve: (UIViewController) -> Void
init(onResolve: #escaping (UIViewController) -> Void) {
self.onResolve = onResolve
}
func makeUIViewController(context: Context) -> ParentResolverViewController {
ParentResolverViewController(onResolve: onResolve)
}
func updateUIViewController(_ uiViewController: ParentResolverViewController, context: Context) { }
}
class ParentResolverViewController: UIViewController {
let onResolve: (UIViewController) -> Void
init(onResolve: #escaping (UIViewController) -> Void) {
self.onResolve = onResolve
super.init(nibName: nil, bundle: nil)
}
required init?(coder: NSCoder) {
fatalError("Use init(onResolve:) to instantiate ParentResolverViewController.")
}
override func didMove(toParent parent: UIViewController?) {
super.didMove(toParent: parent)
if let parent = parent {
onResolve(parent)
}
}
override func viewDidAppear(_ animated: Bool) {
self.parent?.navigationItem.hidesSearchBarWhenScrolling = false
self.parent?.definesPresentationContext = true
self.parent?.navigationController?.navigationBar.sizeToFit()
}
override func viewDidDisappear(_ animated: Bool) {
self.parent?.navigationItem.hidesSearchBarWhenScrolling = false
self.parent?.definesPresentationContext = true
self.parent?.navigationController?.navigationBar.sizeToFit()
}
}
And here's a video of the problem

Answer 1

Set the hidesSearchBarWhenScrolling property before the SearchBar is displayed on the screen. This can be done in viewWillAppear or as in the example below:
struct SearchBarModifier: ViewModifier {
let searchBar: SearchBar
func body(content: Content) -> some View {
content
.overlay(
ViewControllerResolver { viewController in
viewController.navigationItem.searchController = self.searchBar.searchController
viewController.navigationItem.hidesSearchBarWhenScrolling = false
}
.frame(width: 0, height: 0)
)
}
}