如何从 Coordinator 访问 ViewController 类？答案

【问题标题】：How can i access ViewController Class from Coordinator?如何从 Coordinator 访问 ViewController 类？
【发布时间】：2021-09-12 10:04:43
【问题描述】：

我在我的 SwiftUI 中使用 UIViewControllerRepresentable 类，如下所示：

struct CalendarDayView: UIViewControllerRepresentable {

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

   func makeUIViewController(context: Context) -> DayViewController {
       let dayView = DayViewController()
       dayView.delegate = context.coordinator
       return dayView
   }

   func updateUIViewController(_ dayView: DayViewController, context: Context) {
       dayView.delegate = context.coordinator
   }

   typealias UIViewControllerType = DayViewController

   class Coordinator: NSObject, DayViewDelegate {
       
      var parent: CalendarDayView

      init(_ parent: CalendarDayView) {
         self.parent = parent
      }
      
      func dayViewDidSelectEventView(_ eventView: EventView) {
         guard let ckEvent = eventView.descriptor as? EKWrapper else { return }
         let ekEvent = ckEvent.ekEvent
         endEventEditing() // Cannot find 'endEventEditing' in scope
      }

  
   }

}

在 dayViewDidSelectEventView() 函数中，我需要访问来自 DayViewController 类的 endEventEditing() 函数。我已经尝试将父母传递给协调员，但这没有帮助。我无法像这样通过父变量访问 endEventEditing() 函数：

parent.endEventEditing() // Value of type 'CalendarDayView' has no member 'endEventEditing'

那么有没有办法访问由 Coordinator 内部的 makeUIViewController func 生成的 DayViewController 类？

我可以使用/传递dayView 变量

let dayView = DayViewController()

给我的协调员，这样我就可以使用来自这个控制器的功能？

【问题讨论】：

标签： swift swiftui uiviewrepresentable

【解决方案1】：

您可以将它注入到协调器的属性中（使用weak 以避免交叉引用）。

这是一个演示：

struct CalendarDayView: UIViewControllerRepresentable {

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

   func makeUIViewController(context: Context) -> DayViewController {
       let dayView = DayViewController()
       dayView.delegate = context.coordinator
       context.coordinator.viewController = dayView   // << inject !!
       return dayView
   }

   func updateUIViewController(_ dayView: DayViewController, context: Context) {
       dayView.delegate = context.coordinator
   }

   typealias UIViewControllerType = DayViewController

   class Coordinator: NSObject, DayViewDelegate {
      weak var viewController: DayViewController?     // << declare here !!
      var parent: CalendarDayView

      init(_ parent: CalendarDayView) {
         self.parent = parent
      }

      func dayViewDidSelectEventView(_ eventView: EventView) {
         guard let ckEvent = eventView.descriptor as? EKWrapper else { return }
         let ekEvent = ckEvent.ekEvent
         viewController?.endEventEditing()   // << call !!
      }


   }
}

【讨论】：