Building a custom TabView-like view in SwiftUI - ios

Question

I've been trying to build a toolbar-tabview component for macOS that can be composed with child views just like the TabView like bellow:
struct ContentView: View {
var body: some View {
TabView {
Text("First View")
.tabItem {
Image(name: "NSUserAccounts")
Text("First")
}.tag(0)
Text("Second View")
.tabItem {
Image(name: "NSUserAccounts")
Text("Second")
}.tag(1)
}
}
}
At the moment I've something like this:
struct ToolbarTabView<Content>: NSViewControllerRepresentable where Content: View {
let content: () -> Content
init(#ViewBuilder content: #escaping () -> Content) {
self.content = content
}
func makeNSViewController(context: NSViewControllerRepresentableContext<ToolbarTabView>) -> NSTabViewController {
let vc = NSTabViewController()
vc.tabStyle = .toolbar
for item in self.content() as! something? {
let t = NSTabViewItem(viewController: NSHostingController(rootView: item))
t.image = item.image
t.label = item.label
t.identifier = item.identifier
vc.addTabViewItem(t)
}
return vc
}
func updateNSViewController(_ nsViewController: NSTabViewController, context: NSViewControllerRepresentableContext<ToolbarTabView>) {
}
typealias NSViewControllerType = NSTabViewController
}
Is something like this possible with SwiftUI? How is TabView content being casted and used to get Image and Label information?

Answer 1

Instead of just passing content to your ToolbarTabView, you can have it take an array that also contains other values. Try something like this:
struct ToolbarTabView<Content>: NSViewControllerRepresentable where Content: View {
let tabs: [(imageName: String, label: String, identifier: Int, content: () -> Content)]
init(tabs: [(imageName: String, label: String, identifier: Int, content: () -> Content)]) {
self.tabs = tabs
}
func makeNSViewController(context: NSViewControllerRepresentableContext<ToolbarTabView>) -> NSTabViewController {
let vc = NSTabViewController()
vc.tabStyle = .toolbar
for item in tabs {
let t = NSTabViewItem(viewController: NSHostingController(rootView: item.content()))
//t.image = item.image
t.label = item.label
t.identifier = item.identifier // this causes an "unrecognized selector" error, but maybe I'm passing a bad value for this, I'm not sure what it expects
vc.addTabViewItem(t)
}
return vc
}
func updateNSViewController(_ nsViewController: NSTabViewController, context: NSViewControllerRepresentableContext<ToolbarTabView>) {
}
typealias NSViewControllerType = NSTabViewController
}
struct ToolbarTabView_Previews: PreviewProvider {
static var previews: some View {
ToolbarTabView(tabs: [
(
imageName: "My Image",
label: "tab1",
identifier: 0,
content: {
Text("testing")
}
)
])
}
}