如何从 SwiftUI 调用 UIViewController

Question

I have a SwiftUI TabView, with the 2nd tab item needing to show a UIViewController. How can I embed the UIViewController in this second tab?

class MyUIVC: UIViewController {.....}

The following is some pseudocode to what I want:

struct myTabView: View {
@State var selectedTab: Int = 0
var body: some View {
    mySwiftUIView
      .tabItem { Text("First Tab") }
      .tag(0)

    MyUIVC //This is what I want to do with my UIViewController
      .tabItem { Text("Second Tab") }
      .tag(1)
 }
 }

Answer 1

You need to bridge the ViewController using UIViewControllerRepresentable. . Apple provides documentation on how to use that here:

https://developer.apple.com/documentation/swiftui/uiviewcontrollerrepresentable

Additionally, there's a working example of it within their SwiftUI lessons, most notably the lesson titled "Interfacing with UIKit" which can be found here:

https://developer.apple.com/tutorials/swiftui/interfacing-with-uikit

The example ViewController that they're working with looks like this:

struct PageViewController: UIViewControllerRepresentable {
    var controllers: [UIViewController]

    func makeUIViewController(context: Context) -> UIPageViewController {
        let pageViewController = UIPageViewController(
            transitionStyle: .scroll,
            navigationOrientation: .horizontal)

        return pageViewController
    }

    func updateUIViewController(_ pageViewController: UIPageViewController, context: Context) {
        pageViewController.setViewControllers(
            [controllers[0]], direction: .forward, animated: true)
    }

    class Coordinator: NSObject {
        var parent: PageViewController

        init(_ pageViewController: PageViewController) {
            self.parent = pageViewController
        }
    }
}

That being said, the heart and soul of bridging a ViewController is:

1) Create a struct with a unique name for the ViewController that inherits from UIViewControllerRepresentable

2) Implement the function makeUIViewController(context: Context) with a return type of the UIViewController

3) Implement the function updateUIViewController(_ uiViewController: YourUIViewController, context: Context) without a return

4) As needed, implement a Coordinator class that inherits from NSObject as well as any delegate protocols you need.

There is a bit more depending on what you need that ViewController to do, but this should get you pointed in the right direction.