将 @EnvironmentObject 属性与 CADisplayLink 结合使用

Question

我正在尝试为某些动画实现CADisplayLink ，但是当我尝试从MyAnimations类内部访问我的MainData环境对象属性时，我收到了致命错误No ObservableObject of type MainData found. A View.environmentObject(_:) for MainData may be missing as an ancestor of this view. No ObservableObject of type MainData found. A View.environmentObject(_:) for MainData may be missing as an ancestor of this view.

在 SceneDelegate 中，我将MainData设置为ContentView上的环境对象：

class SceneDelegate: UIResponder, UIWindowSceneDelegate {

    var window: UIWindow?

    var mainData = MainData()

    func scene(_ scene: UIScene, willConnectTo session: UISceneSession, options connectionOptions: UIScene.ConnectionOptions) {
        // Use this method to optionally configure and attach the UIWindow `window` to the provided UIWindowScene `scene`.
        // If using a storyboard, the `window` property will automatically be initialized and attached to the scene.
        // This delegate does not imply the connecting scene or session are new (see `application:configurationForConnectingSceneSession` instead).

        // Create the SwiftUI view that provides the window contents.
        let contentView = ContentView()

        // Use a UIHostingController as window root view controller.
        if let windowScene = scene as? UIWindowScene {
            let window = UIWindow(windowScene: windowScene)
            
            window.rootViewController = UIHostingController(rootView: contentView.environmentObject(self.mainData))
            
            self.window = window
            window.makeKeyAndVisible()
        }
    }

...

}

这是带有CADisplayLink的类。 createDisplayLink()从ContentView调用：

class MyAnimations: NSObject{
    @EnvironmentObject var mainData: MainData

    
    func createDisplayLink() {
        let displaylink = CADisplayLink(target: self, selector: #selector(step))
        
        displaylink.add(to: .current, forMode: RunLoop.Mode.default)
    }
    

    @objc func step(link: CADisplayLink) {
        mainData.displayLinkY += 1.5   //Error here
        mainData.displayLinkX += 1.5
    }
    
    
} 

我的问题是：如何从step()内部更改环境对象属性displayLinkX和displayLinkY ？

Answer 1

只需删除@EnvironmentObject属性包装器，它仅适用于 SwiftUI

class MyAnimations: NSObject{
    var mainData: MainData

    init(mainData: MainData) {
      self.mainData = mainData
        super.init()
    }

    // ... other code
}