SwiftUI 5：如何锁定特定视图的方向

Posted 2023-03-10

【中文标题】SwiftUI 5：如何锁定特定视图的方向

【英文标题】：SwiftUI 5: How to lock orientation for a specific view

【发布时间】：2021-12-04 09:28:08

【问题描述】：

在我的相机视图中，我想将方向保持为纵向，因为当它处于横向时，相机预览不会旋转：

struct CameraPreview: UIViewRepresentable 
    
    @ObservedObject var camera: CameraModel
    
    func makeUIView(context: Context) -> some UIView 
        
        let view = UIView(frame: UIScreen.main.bounds)
        
        camera.preview = AVCaptureVideoPreviewLayer(session: camera.session)
        
        //...
        camera.preview.videoGravity = .resizeAspectFill
        camera.preview.frame = view.frame
        view.layer.addSublayer(camera.preview)
        
        
        // starting session
        camera.session.startRunning()
        
        return view
    
    
    func updateUIView(_ uiView: UIViewType, context: Context) 
        
    
    

我知道我迟早需要解决这个问题，但我需要行动起来。现在，我将阻止所有其他方向，除了：

struct CameraView: View 
    init() 
        let value = UIInterfaceOrientation.portrait.rawValue
        UIDevice.current.setValue(value, forKey: "orientation")
    

[..]

通过执行上述操作，当放置在横向时，相机预览会减半，然后 init “开始”将其设置回 CameraView 回到纵向。如何让它在没有任何动画的情况下保持纵向模式？

将代码放在.onAppear 中没有任何作用：

struct CameraView: View 
  var body: some View 

    VStack..
      .onAppear(perform: 
        let value = UIInterfaceOrientation.portrait.rawValue
        UIDevice.current.setValue(value, forKey: "orientation")
      
  

【参考方案1】：

原来我已经修复了旋转：

func updateUIView(_ uiView: UIViewType, context: Context) 
    let view = UIView(frame: UIScreen.main.bounds)
    let statusBarOrientation = UIApplication.shared.windows.first?.windowScene?.interfaceOrientation
    let videoOrientation: AVCaptureVideoOrientation = statusBarOrientation?.videoOrientation ?? .portrait
    camera.preview.frame = view.frame
    camera.preview.connection?.videoOrientation = videoOrientation

对于videoOrientation，请参阅Jack's answer。

import AVFoundation

extension UIInterfaceOrientation 
    var videoOrientation: AVCaptureVideoOrientation? 
        switch self 
        case .portraitUpsideDown: return .portraitUpsideDown
        case .landscapeRight: return .landscapeRight
        case .landscapeLeft: return .landscapeLeft
        case .portrait: return .portrait
        default: return nil