问试图在UIViewController中使用UIkit中的my UIkit使协议无法向可表示的

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//ContentView.swift
import SwiftUI

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

struct ContentView_Previews: PreviewProvider {
   static var previews: some View {
     ContentView()
   }
}

//UIViewController.swift
import SwiftUI
import UIKit

struct UIViewController: UIViewControllerRepresentable { //error: Type 'UIViewController' does not conform to protocol 'UIViewControllerRepresentable'
   func makeUIViewController(context: Context) -> ViewController{
      return ViewController()
   }
}

struct UIViewController_Previews: PreviewProvider {
  static var previews: some View {
      UIViewController()
  }
}

//ViewController.swift
import UIKit
import Metal

class ViewController: UIViewController { //error: Inheritance from non-protocol, non-class type 'UIViewController'
  var device: MTLDevice!
  var metalLayer: CAMetalLayer!

//created is the buffer to send the points over to gpu
var vertexBuffer: MTLBuffer!

//starts the render pipeline
var pipelineState: MTLRenderPipelineState!

//command queue
var commandQueue: MTLCommandQueue!

//timer to render the screen frame by frame
var timer: CADisplayLink!

//insuring the view is loaded so the device can actually be used
override func viewDidLoad() { //error: Method does not override any method from its superclass
  super.viewDidLoad()
    
  device = MTLCreateSystemDefaultDevice()
    
  metalLayer = CAMetalLayer()
  metalLayer.device = device
  metalLayer.pixelFormat = .bgra8Unorm
  metalLayer.framebufferOnly = true
  metalLayer.frame = view.layer.frame
  view.layer.addSublayer(metalLayer) //error: Use of unresolved identifier 'view'
  ....