I'm trying to used matchedGeometryEffect on a pair of views. It works well until you navigate to a child view and then back, in which case the matchedGeometryEffect seems broken briefly (the red rectangle is instantly visible when I try expanding my view)
Is there something I'm missing?
struct ContentView: View {
@Namespace private var namespace
@State private var expanded = false
var body: some View {
NavigationView {
VStack {
NavigationLink("Click Me") {
Text("Hello, world")
}
Group {
if expanded {
Rectangle()
.foregroundColor(.red)
.matchedGeometryEffect(id: "Rect", in: namespace)
.frame(width: 300, height: 300)
}
else {
Rectangle()
.foregroundColor(.blue)
.matchedGeometryEffect(id: "Rect", in: namespace)
.frame(width: 50, height: 50)
}
}
.onTapGesture {
withAnimation(.linear(duration: 2.0)) {
expanded.toggle()
}
}
}
}
}
}
Selecting any option will automatically load the page
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I'm using a UITabController in my SwiftUI app and it works well, except for one issue.
When I have a NavigationView that uses a large title, it changes to inline as I scroll, as expected. So far so good.
When I switch tabs, then switch back again, it should remember the scroll position and therefore be inline. Instead, it very briefly flickers as a large title before moving to inline.
This only seems to happen on device.
Screen Recording - https://developer.apple.com/forums/content/attachment/8e27f663-5350-4751-8d70-2b41fc12b40f
Is any able to help me with a workaround?
struct ContentView: View {
var body: some View {
CustomTabView([
Tab(view: FirstView(),
barItem: UITabBarItem(title: "First", image: UIImage(systemName: "1.circle"), selectedImage: nil)),
Tab(view: SecondView(),
barItem: UITabBarItem(title: "Second", image: UIImage(systemName: "2.circle"), selectedImage: nil))
])
}
}
struct FirstView: View {
var body: some View {
NavigationView {
List {
ForEach( 0...40, id: \.self ) {
Text("\($0)")
.padding()
}
}
.navigationTitle("First View")
}
}
}
struct SecondView: View {
var body: some View {
NavigationView {
List {
ForEach( 41...80, id: \.self ) {
Text("\($0)")
.padding()
}
}
.navigationTitle("Second View")
}
}
}
struct TabBarController: UIViewControllerRepresentable {
var controllers: [UIViewController]
func makeUIViewController(context: Context) - UITabBarController {
let tabBarController = UITabBarController()
tabBarController.viewControllers = controllers
tabBarController.delegate = context.coordinator
return tabBarController
}
func updateUIViewController(_ uiViewController: UITabBarController, context: Context) {}
func makeCoordinator() - Coordinator {
Coordinator()
}
class Coordinator: NSObject, UITabBarControllerDelegate {
func tabBarController(_ tabBarController: UITabBarController, shouldSelect viewController: UIViewController) - Bool {
guard let fromView = tabBarController.selectedViewController?.view, let toView = viewController.view else {
return false
}
if fromView != toView {
fromView.superview!.addSubview(toView)
}
return true
}
}
}
struct CustomTabView: View {
var viewControllers: [UIHostingControllerAnyView]
init(_ tabs: [Tab]) {
self.viewControllers = tabs.map {
let host = UIHostingController(rootView: $0.view)
host.tabBarItem = $0.barItem
return host
}
}
var body: some View {
TabBarController(controllers: viewControllers)
.edgesIgnoringSafeArea(.all)
}
}
struct Tab {
var view: AnyView
var barItem: UITabBarItem
initV: View(view: V, barItem: UITabBarItem) {
self.view = AnyView(view)
self.barItem = barItem
}
}