SwiftUI iOS-如何使用捕获的硬件键事件

Question

如何在SwiftUI中使用按键信息？我尝试使用@EnvironmentObject与我的SwiftUI共享密钥，但每次sendKeybKey中都崩溃：线程1：致命错误：未找到UserData类型的ObservableObject。作为该视图的祖先，可能缺少UserData的View.environmentObject（_ :)。在.environmentObject中已经在SceneDelegate中使用过，但是错了吗？我的代码：

class KeyTestController<Content>: UIHostingController<Content> where Content: View {
@EnvironmentObject var userData: UserData
override func becomeFirstResponder() -> Bool {
        true
}
override var keyCommands: [UIKeyCommand]? {
        var keys = [UIKeyCommand]()

        for num in "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz!\r" {
        keys.append(
                    UIKeyCommand(
                                    input:String(num),
                                    modifierFlags: [],
                                    action:
                                    #selector(sendKeybKey)
                                )
                    )
    }
    return keys
}
@objc func sendKeybKey(_ sender: UIKeyCommand) {
        userData.collectChar = sender.input ?? ""
        print(">>> test was pressed \(sender.input ?? "")")
}

}

在SceneDelegate中

 if let windowScene = scene as? UIWindowScene {
    let window = UIWindow(windowScene: windowScene)
    window.rootViewController = KeyTestController/*UIHostingController*/(
        rootView: myList()
        .environmentObject(UserData())
    )
    self.window = window
    window.makeKeyAndVisible()
}

和UserData：

    final class UserData: ObservableObject  {
    @Published var datasetUIIdata: [DatasetUII] = []
    @Published var collectChar : String = ""
    @Published var collectText : String = ""
}

我的SwiftUI视图

struct myList: View {
@EnvironmentObject var userData: UserData

var body: some View {
    VStack {
        HStack {
                Text("Key\(userData.collectChar)").font(.largeTitle)
            }
        .padding()
        List {
            ForEach(userData.datasetUIIdata, id: \.self) { (item) in
                Text(item.userName)
            }
            .onDelete(perform: delete)
        }
        .padding()
    }
}
func delete(at offsets: IndexSet) {
    userData.datasetUIIdata.remove(atOffsets: offsets)
}

}

有人想为新手提供快速帮助吗？

谢谢！

瓦尔德玛

Answer 1

您在控制器中不需要@EnvironmentObject，UserData是引用类型，因此您可以在视图和控制器中直接注入相同的对象。

class KeyTestController<Content>: UIHostingController<Content> where Content: View {
      var userData: UserData

因此创建如下：>

 if let windowScene = scene as? UIWindowScene {
    let window = UIWindow(windowScene: windowScene)

    let userData = UserData()
    let contentView = myList().environmentObject(userData)      // in view !!

    let controller = KeyTestController(rootView: contentView)
    controller.userData = userData                              // in controller !!

    window.rootViewController = controller