SwiftUI中使用UIKit

使用UIViewController

实现以下方法

@Binding var uiImage: UIImage?
@Environment(\.presentationMode) var presentationMode

func makeUIViewController(context: Context) -> UIImagePickerController {
    
    let picker = UIImagePickerController()
    picker.delegate = context.coordinator
    
    return picker
}

func updateUIViewController(_ uiViewController: UIImagePickerController, context: Context) {
    
}

func makeCoordinator() -> Coordinator {
    Coordinator(self)
}

// 相册库代理
class Coordinator: NSObject, UIImagePickerControllerDelegate, UINavigationControllerDelegate {
    
    var parent: ImagePickerView
    
    init(_ parent: ImagePickerView) {
        self.parent = parent
    }
    
    func imagePickerController(_ picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [UIImagePickerController.InfoKey : Any]) {
        if let uiImage = info[.originalImage] as? UIImage {
            parent.uiImage = uiImage
            parent.presentationMode.wrappedValue.dismiss()
        }
    }
}

在SwiftUI中使用

ImagePickerView(uiImage: self.$uiImage)

回调实现

以保存图片到相册为例
新建一个ImageSaver类，利用闭包进行回调，这也是三方库对外提供服务的常用手段

class ImageSaver: NSObject {
    
    var successHandler: (() -> Void)?
    var errorHandler: ((Error) -> Void)?
    
    func save(uiImage: UIImage) {
        UIImageWriteToSavedPhotosAlbum(uiImage, self, #selector(saveError), nil)
    }
    
    @objc func saveError(_ image: UIImage, _ error: Error?, _ contextInfo: UnsafeRawPointer) {
        if let error = error {
            errorHandler?(error)
        } else {
            successHandler?()
        }
    }
}

使用

Button("保存"){
    guard let uiImage = self.uiImage else { return }
    let imageSaver = ImageSaver()
    imageSaver.successHandler = {
        print("保存成功")
    }
    imageSaver.errorHandler = { error in
        print(error.localizedDescription)
    }
    
    imageSaver.save(uiImage: uiImage)
}

使用UIView

与使用UIViewController类似的流程

struct MapView: UIViewRepresentable {
    func makeUIView(context: Context) -> MKMapView {
        return MKMapView()
    }
    
    func updateUIView(_ uiView: MKMapView, context: Context) {
        
    }
}

struct MapView_Previews: PreviewProvider {
    static var previews: some View {
        MapView()
    }
}