UIDocumentPickerViewController in SwiftUI on mac (macCatalyst)

Question

因此，我一直在“移动”一个小型SwiftUI iPad应用程序到Mac，并与UIDocumentPickerViewController发生了一点碰撞。我已经将UIDocumentPickerViewController封装在一个UIViewControllerRepresentable中，如下所示：

struct DocumentPickerView: UIViewControllerRepresentable {
  func makeUIViewController(context: Context) -> UIDocumentPickerViewController {
    let documentPicker = UIDocumentPickerViewController(documentTypes: [(kUTTypeImage as String)], in: .import)
    return documentPicker
  }

  func updateUIViewController(_ uiViewController: UIDocumentPickerViewController, context: Context) {

  }
}

并以如下方式显示：

struct ContentView: View {
@State var shows = false
var body: some View {
    Button(action: { self.shows.toggle() }) {
        Text("Select File")
    }
    .sheet(isPresented: self.$shows) {
        DocumentPickerView()
    }
  }
}

On iPad all运行良好，

​

但是在Mac上，UIDocumentPickerViewController没有显示，我们得到了这个空白模式：

​

​

Answer 1

我替换了不推荐的方法，并为提供的主题启动代码启用了询问权限，它可以工作。

用Xcode 13.3 / macOS 12.2测试

import UniformTypeIdentifiers
struct DocumentPickerView: UIViewControllerRepresentable {
  func makeUIViewController(context: Context) -> UIDocumentPickerViewController {
    let documentPicker = UIDocumentPickerViewController(forOpeningContentTypes: [UTType.image], asCopy: true)
    return documentPicker
  }

  func updateUIViewController(_ uiViewController: UIDocumentPickerViewController, context: Context) {

  }
}

​

​

并演示开放标准macOS选择器

​

​

Answer 2

由于某些原因(我不知道更多的具体细节)，以下内容对我起了作用(对于催化剂)：

而不是使用in: .import

let documentPicker = UIDocumentPickerViewController(
    documentTypes: [(kUTTypeImage as String)], 
    in: .import
)

使用in: .open

let documentPicker = UIDocumentPickerViewController(
    documentTypes: [(kUTTypeImage as String)], 
    in: .open
)

我还没有检查功能是否在iOS中维护，但也许您可以使用某种“标志”来确定是使用.import还是.open