【发布时间】：2020-09-05 21:27:50
【问题描述】：
我上课了：
class ImagePickerCoordinator: NSObject, UINavigationControllerDelegate, UIImagePickerControllerDelegate, ObservableObject{
@Published var display = "Name"
@Binding var image: UIImage?
@Binding var isShown: Bool
init(image: Binding<UIImage?>, isShown: Binding<Bool>){
_image = image
_isShown = isShown
}
func imagePickerController(_ picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [UIImagePickerController.InfoKey : Any]) {
if let uiImage = info[UIImagePickerController.InfoKey.originalImage] as? UIImage {
guard let convertedCIImage = CIImage(image: uiImage) else {
fatalError("Cannot convert UIImage to CIIMage.")
}
detectFlower(image: convertedCIImage) { (flowerString, error) in
self.display = flowerString!
}
image = uiImage
isShown = false
}
}
func imagePickerControllerDidCancel(_ picker: UIImagePickerController) {
isShown = false
}
func detectFlower(image: CIImage,completion: @escaping (_ getString:String?,_ error:Error?)-> Void) {
guard let model = try? VNCoreMLModel(for: FlowerModels().model) else {
fatalError("Cannot import a model.")
}
let request = VNCoreMLRequest(model: model) { (request, error) in
let classification = request.results?.first as? VNClassificationObservation
let nameOfFlower = String(classification?.identifier ?? "Unexpected type")
completion(nameOfFlower,nil)
}
let handler = VNImageRequestHandler(ciImage: image)
do {
try handler.perform([request])
} catch {
print(error)
completion(nil,error)
}
}
}
struct ImagePicker: UIViewControllerRepresentable {
typealias UIViewControllerType = UIImagePickerController
typealias Coordinator = ImagePickerCoordinator
@Binding var image: UIImage?
@Binding var isShown: Bool
var sourceType: UIImagePickerController.SourceType = .camera
func updateUIViewController(_ uiViewController: UIImagePickerController, context: UIViewControllerRepresentableContext<ImagePicker>) {
}
func makeCoordinator() ->ImagePicker.Coordinator {
return ImagePickerCoordinator(image: $image, isShown: $isShown)
}
func makeUIViewController(context: UIViewControllerRepresentableContext<ImagePicker>) -> UIImagePickerController {
let picker = UIImagePickerController()
picker.sourceType = sourceType
picker.delegate = context.coordinator
return picker
}
}
我在其中初始化了@Published var display，它接收函数 imagePickerController 中的 detectFlower() 函数的结果。在结构 ScanWithCamera 中，我想使用此值在 Text() 中设置文本。我在 struct @EnvironmentObject var env: ImagePickerCoordinator 中初始化并设置了 Text(env.display)，但我得到一个致命错误：没有找到 ImagePickerCoordinator 类型的 ObservableObject。 ImagePickerCoordinator 的 View.environmentObject(_:) 作为该视图的祖先可能会丢失。
struct ScanWithCamera: View {
@State private var showSheet: Bool = false
@State private var showImagePicker: Bool = false
@State private var sourceType: UIImagePickerController.SourceType = .camera
@State private var userImage: UIImage?
@EnvironmentObject var env: ImagePickerCoordinator
var body: some View {
NavigationView{
VStack{
Text(env.display)
.foregroundColor(.blue)
.font(.system(size: 25))
Image(uiImage: userImage ?? UIImage(named: "flower_logo")!)
.resizable()
.aspectRatio(contentMode: .fit)
.frame(width: 400, height: 400)
}
.frame(minWidth: 0, maxWidth: .infinity, minHeight: 0, maxHeight: .infinity, alignment: .top)
}
.navigationBarTitle(Text(""), displayMode: .inline)
.navigationBarItems(trailing:
HStack {
Button("Camera") {
self.showImagePicker = true
self.sourceType = .photoLibrary
print("Camera tapped!")
}
}
)
.sheet(isPresented: $showImagePicker) {
ImagePicker(image: self.$userImage, isShown: self.$showImagePicker, sourceType: self.sourceType).environmentObject(self.env)
}
}
}
如何将此文本从类函数传递到结构？
【问题讨论】：
标签： swift binding swiftui swiftui-environment