有没有一种方法可以从类的扩展中访问函数中的回调？

Question

在本地响应中，我使用NativeModules和RCTResponseSenderBlock创建回调。因为回调特定于我在网桥中声明的函数，所以无法从提供所需反馈的扩展中访问它。这是基于Mapbox Navigation iOS SDK中的示例代码构建的。

我尝试了各种方法来通过扩展类访问回调属性。

@objc(TbtNavigation)
class TbtNavigation: NSObject {
  @objc
  func takeMeToWH(_ callback: RCTResponseSenderBlock) {
    let origin = Waypoint(coordinate: CLLocationCoordinate2D(latitude: 38.9131752, longitude: -77.0324047), name: "Mapbox")
    let destination = Waypoint(coordinate: CLLocationCoordinate2D(latitude: 38.8977, longitude: -77.0365), name: "White House")
    let options = NavigationRouteOptions(waypoints: [origin, destination])
    Directions.shared.calculate(options) { (waypoints, routes, error) in
      guard let route = routes?.first else { return }
      let navigationViewController = NavigationViewController(for: route)
      navigationViewController.delegate = self
      let appDelegate = UIApplication.shared.delegate
      appDelegate!.window!!.rootViewController!.present(navigationViewController, animated: true, completion: nil)
    }
    callback(["CALLBACK WORKS HERE"])
  }
}

extension TbtNavigation: NavigationViewControllerDelegate {
  // Show an alert when arriving at the waypoint and wait until the user to start next leg.

  func navigationViewControllerDidDismiss(_ navigationViewController: NavigationViewController, byCanceling canceled: Bool) {
    print("cancelled")
    callback(["I NEED THE CALLBACK TO WORK HERE"])
    let appDelegate = UIApplication.shared.delegate
    appDelegate!.window!!.rootViewController!.dismiss(animated: true, completion: nil)
  }
}

navigationViewController中的回调是“未解析的标识符”

编辑：解决方案是在类范围内声明回调变量。

@objc(TbtNavigation)
class TbtNavigation: NSObject {
  var callback: RCTResponseSenderBlock?

  @objc
  func takeMeToWH(_ callback: @escaping RCTResponseSenderBlock) {
    let origin = Waypoint(coordinate: CLLocationCoordinate2D(latitude: 38.9131752, longitude: -77.0324047), name: "Mapbox")
    let destination = Waypoint(coordinate: CLLocationCoordinate2D(latitude: 38.912605, longitude: -77.035402), name: "White House")
    let options = NavigationRouteOptions(waypoints: [origin, destination])
    Directions.shared.calculate(options) { (waypoints, routes, error) in
      guard let route = routes?.first else { return }
      let navigationViewController = NavigationViewController(for: route)
      navigationViewController.delegate = self
      let appDelegate = UIApplication.shared.delegate
      appDelegate!.window!!.rootViewController!.present(navigationViewController, animated: true, completion: nil)
    }
    self.callback = callback
  }
}
extension TbtNavigation: NavigationViewControllerDelegate {
  // Show an alert when arriving at the waypoint and wait until the user to start next leg.

  func navigationViewControllerDidDismiss(_ navigationViewController: NavigationViewController, byCanceling canceled: Bool) {
    self.callback?([canceled])
    let appDelegate = UIApplication.shared.delegate
    appDelegate!.window!!.rootViewController!.dismiss(animated: true, completion: nil)
  }
}