正如您所提到的，您需要通过UIViewControllerRepresentable将组件连接到SwiftUI.
下面是一个简单的实现:
struct MailView: UIViewControllerRepresentable {
@Binding var isShowing: Bool
@Binding var result: Result<MFMailComposeResult, Error>?
class Coordinator: NSObject, MFMailComposeViewControllerDelegate {
@Binding var isShowing: Bool
@Binding var result: Result<MFMailComposeResult, Error>?
init(isShowing: Binding<Bool>,
result: Binding<Result<MFMailComposeResult, Error>?>) {
_isShowing = isShowing
_result = result
}
func mailComposeController(_ controller: MFMailComposeViewController,
didFinishWith result: MFMailComposeResult,
error: Error?) {
defer {
isShowing = false
}
guard error == nil else {
self.result = .failure(error!)
return
}
self.result = .success(result)
}
}
func makeCoordinator() -> Coordinator {
return Coordinator(isShowing: $isShowing,
result: $result)
}
func makeUIViewController(context: UIViewControllerRepresentableContext<MailView>) -> MFMailComposeViewController {
let vc = MFMailComposeViewController()
vc.mailComposeDelegate = context.coordinator
return vc
}
func updateUIViewController(_ uiViewController: MFMailComposeViewController,
context: UIViewControllerRepresentableContext<MailView>) {
}
}
Usage:
struct ContentView: View {
@State var result: Result<MFMailComposeResult, Error>? = nil
@State var isShowingMailView = false
var body: some View {
VStack {
if MFMailComposeViewController.canSendMail() {
Button("Show mail view") {
self.isShowingMailView.toggle()
}
} else {
Text("Can't send emails from this device")
}
if result != nil {
Text("Result: \(String(describing: result))")
.lineLimit(nil)
}
}
.sheet(isPresented: $isShowingMailView) {
MailView(isShowing: self.$isShowingMailView, result: self.$result)
}
}
}
(在运行iOS 13的iPhone 7 Plus上测试——效果非常好)
Updated for Xcode 11.4