SwiftUI中如何从UIViewControllerRepresentable的Coordinator访问对应ViewController

你无法通过SwiftUI层的CalendarDayView结构体访问UIKit层的DayViewController实例，只需为Coordinator新增一个对DayViewController的弱引用属性，在创建控制器时赋值即可： #

实现步骤 #

• 在Coordinator类中新增weak修饰的DayViewController可选属性，避免出现循环引用
• 在makeUIViewController方法中创建完控制器后，将实例赋值给Coordinator的对应属性
• 业务中如果存在updateUIViewController时替换控制器实例的场景，需要在update方法中同步更新Coordinator持有的引用

完整修改后代码 #

struct CalendarDayView: UIViewControllerRepresentable {

   func makeCoordinator() -> Coordinator {
       return Coordinator(self)
   }

   func makeUIViewController(context: Context) -> DayViewController {
       let dayView = DayViewController()
       dayView.delegate = context.coordinator
       // 给Coordinator赋值控制器引用
       context.coordinator.dayViewController = dayView
       return dayView
   }

   func updateUIViewController(_ dayView: DayViewController, context: Context) {
       dayView.delegate = context.coordinator
       // 同步更新引用，避免控制器替换后调用失效
       context.coordinator.dayViewController = dayView
   }

   typealias UIViewControllerType = DayViewController

   class Coordinator: NSObject, DayViewDelegate {
       
      var parent: CalendarDayView
      // 新增弱引用属性存储控制器实例
      weak var dayViewController: DayViewController?

      init(_ parent: CalendarDayView) {
         self.parent = parent
      }
      
      func dayViewDidSelectEventView(_ eventView: EventView) {
         guard let ckEvent = eventView.descriptor as? EKWrapper else { return }
         let ekEvent = ckEvent.ekEvent
         // 调用控制器方法
         dayViewController?.endEventEditing()
      }

   }

}

内容的提问来源于stack exchange，提问作者Niklas