SwiftUI - 如何处理相机权限？

Question

我的 ImagePicker 按预期工作。但是，我正在尝试实现相机权限处理，但我似乎陷入了困境。我收到错误：“函数中缺少返回预期返回 UIImagePickerController”，这是理所当然的。我不确定还能在哪里放置 switch 语句来执行处理。任何帮助表示赞赏。

struct ImagePicker: UIViewControllerRepresentable {
    
    var sourceType: UIImagePickerController.SourceType = .photoLibrary
    
    @Binding var selectedImage: UIImage
    @Binding var alertCameraAccessNeeded: Bool
    @Environment(\.presentationMode) private var presentationMode
    @EnvironmentObject private var userManager: UserManager
    
    let cameraAuthStatus = AVCaptureDevice.authorizationStatus(for: .video)
    
    func makeUIViewController(context: UIViewControllerRepresentableContext<ImagePicker>) -> UIImagePickerController {
        
        switch cameraAuthStatus {
        case .notDetermined: requestCameraPermission()
        case .authorized:
            
            let imagePicker = UIImagePickerController()
            imagePicker.delegate = context.coordinator
            imagePicker.allowsEditing = true
            imagePicker.sourceType = sourceType
            
            return imagePicker
            
        case .restricted, .denied: self.alertCameraAccessNeeded = true
            
        @unknown default:
            fatalError()
        }
        
        
    }
    
    func requestCameraPermission() {
        AVCaptureDevice.requestAccess(for: .video, completionHandler: {accessGranted in
            guard accessGranted == true else { return }
            
        })
    }
    
    func makeCoordinator() -> Coordinator {
        Coordinator(self, userManager: userManager)
    }
    
    
    func updateUIViewController(_ uiViewController: UIImagePickerController, context: UIViewControllerRepresentableContext<ImagePicker>) {
        
    }
    
    
    class Coordinator: NSObject, UIImagePickerControllerDelegate, UINavigationControllerDelegate {
        
        let parent: ImagePicker
        let userManager: UserManager
        
        
        init(_ parent: ImagePicker, userManager: UserManager) {
            self.parent = parent
            self.userManager = userManager
        }
        
        func imagePickerController(_ picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [UIImagePickerController.InfoKey : Any]) {
            
            if let image = info[.editedImage] as? UIImage {
                parent.selectedImage = image
                userManager.uploadProfilePicture(image: image)
            }
            
            
            parent.presentationMode.wrappedValue.dismiss()
        }
    }
}

Answer 1

为了回应您的评论，想知道如何请求权限并仅有条件地显示图像选择器，这里有一个简单的示例，它允许您强制执行操作（例如，设置 @State 变量）或有条件地显示视图，如果你有许可。

在 中请求许可onAppear，但也可以移动到按下按钮或类似的操作。

class CameraManager : ObservableObject {
    @Published var permissionGranted = false
    
    func requestPermission() {
        AVCaptureDevice.requestAccess(for: .video, completionHandler: {accessGranted in
            DispatchQueue.main.async {
                self.permissionGranted = accessGranted
            }
        })
    }
}

struct ContentView: View {
    @StateObject var cameraManager = CameraManager()
    
    var body: some View {
        VStack {
            Text("Hello, world")
            if cameraManager.permissionGranted {
                //show a conditional view only if you have permission
            }
        }
        .onReceive(cameraManager.$permissionGranted, perform: { (granted) in
            if granted {
                //show image picker controller
            }
        })
        .onAppear {
            cameraManager.requestPermission()
        }
    }
}