将@EnvironmentObject 属性与 CADisplayLink 一起使用

Question

我正在尝试为某些动画实现 CADisplayLink，但是当我尝试从 class MyAnimations 内部访问我的 MainData 环境对象属性时，我得到致命错误 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()
        }
    }

...

}

这里是 class 和 CADisplayLink。 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
}

将@EnvironmentObject 属性与 CADisplayLink 一起使用

Using @EnvironmentObject properties with CADisplayLink

cadisplaylink

swift

swiftui