我想在 iOS 13 及更高版本上运行此代码我应该如何修复此错误？我想让这段代码也可以在 iOS 13 上运行。
@available(iOS 14.0, *)
@main
struct WeatherProApp: App {
@Environment(\.scenePhase) private var scenePhase
@UIApplicationDelegateAdaptor(AppDelegate.self) var appDelegate
var body: some Scene {
WindowGroup{
let fetcher = WeatherFetcher()
let viewModel = WeeklyWeatherViewModel(weatherFethcer: fetcher)
WeeklyWeatherView(viewModel: viewModel)
}
.onChange(of: scenePhase) { (newScenePhase) in
switch newScenePhase {
case .active:
print("scene is now active!")
case .inactive:
print("scene is now inactive!")
case .background:
print("scene is now in the background!")
@unknown default:
print("Apple must have added something new!")
}
}
}
} …我想在SwiftUI中创建一个自定义文本字段来处理第一响应者，但是我在代码中遇到此错误，并且struct是不可变的，我不知道该怎么办？
struct CustomTextField: UIViewRepresentable {
class Coordinator: NSObject, UITextFieldDelegate {
@Binding var text: String
var didBecomeFirstResponder = false
init(txt: Binding<String>) {
self.$text = txt
}
func textFieldDidChangeSelection(_ textField: UITextField) {
text = textField.text ?? ""
}
}
@Binding var text: String
var isFirstResponder: Bool = false
func makeUIView(context: UIViewRepresentableContext<CustomTextField>) -> UITextField {
let textField = UITextField(frame: .zero)
textField.delegate = context.coordinator
return textField
}
func makeCoordinator() -> CustomTextField.Coordinator {
return Coordinator(txt: $text)
}
func updateUIView(_ uiView: UITextField, context: UIViewRepresentableContext<CustomTextField>) {
uiView.text …