how to rerender a uikit view via swiftui?

To rerender a UIKit view via SwiftUI, you can use the UIViewRepresentable protocol to wrap your UIKit view and integrate it into your SwiftUI view hierarchy. This allows you to update the UIKit view using SwiftUI's declarative syntax.

Here's a step-by-step guide based on the information from the WWDC sessions:

1. Create a UIViewRepresentable: This protocol allows you to create and update a UIKit view using SwiftUI.

   struct MyUIKitView: UIViewRepresentable {
       func makeUIView(context: Context) -> UIView {
           // Create and return the UIKit view
       }
   
       func updateUIView(_ uiView: UIView, context: Context) {
           // Update the UIKit view with new data
       }
   }
   

2. Use the UIViewRepresentable in SwiftUI: You can now use this representable view in your SwiftUI view hierarchy like any other SwiftUI view.

   struct ContentView: View {
       var body: some View {
           MyUIKitView()
       }
   }
   

3. Animating UIKit Views with SwiftUI Animations: If you need to animate the UIKit view, you can bridge the animation from SwiftUI to UIKit. Use the new animate method on the context to apply any animation on the transaction associated with the update.

   struct MyUIKitView: UIViewRepresentable {
       @Binding var isOpen: Bool
   
       func makeUIView(context: Context) -> UIView {
           // Create and return the UIKit view
       }
   
       func updateUIView(_ uiView: UIView, context: Context) {
           // Bridge the animation from SwiftUI to UIKit
           UIView.animate(withDuration: context.transaction.animation?.duration ?? 0) {
               uiView.alpha = self.isOpen ? 1.0 : 0.0
           }
       }
   }
   

For more detailed information, you can refer to the following sessions from WWDC:

• SwiftUI essentials (20:45)
• Enhance your UI animations and transitions (10:23)

These sessions cover the interoperability between SwiftUI and UIKit, and how to animate UIKit views using SwiftUI animations.