ios - 在 SwiftUI 中检测并转发屏幕上任意位置的点击

Question

在 SwiftUI 应用程序中，我需要检测屏幕上的任何点击。只检测，然后将其转发到底层 View 。作为一个用例，考虑将“在线”用户状态更新发送到服务器以响应任何用户事件。

我当然不想为此目的向每个 View 添加手势识别器。我尝试在 SceneDelegate 中添加一个全局的。只要检测到任何点击，这都有效:

func scene(_ scene: UIScene, willConnectTo session: UISceneSession, options connectionOptions: UIScene.ConnectionOptions) {        
    // ... snip other code
    initGlobalTapRecognizer()
}

// MARK: UIGestureRecognizerDelegate
extension SceneDelegate: UIGestureRecognizerDelegate {
    func initGlobalTapRecognizer() {
        let tapGesture = UITapGestureRecognizer(target: self, action: nil)
        tapGesture.delegate = self
        window?.addGestureRecognizer(tapGesture)
    }

    func gestureRecognizer(_ gestureRecognizer: UIGestureRecognizer, shouldReceive touch: UITouch) -> Bool {
        print("tapped")
        return true
    }
}

但这会破坏一些 SwiftUI 控件。例如，按钮可以工作，但 TabView 不再响应点击。

我尝试了另一种方法，使用 simultaneousGesture如 suggest here :

struct ContentView: View {
    @State var selectedTab: Int = 1

    var body: some View {
        TabView(selection: $selectedTab) {
            VStack {
                Text("tab 1")
                Button(action: { print("button 1 click") }, label: { Text("button 1") })
            }
            .tabItem( { Text("tab 1") } )
            .tag(1)

            VStack {
                Text("tab 2")
            }
            .tabItem( { Text("tab 2") } )
            .tag(2)
        }
        .contentShape(Rectangle())
        .simultaneousGesture(TapGesture().onEnded({ print("simultaneous gesture tap") }))
    }
}

相同的结果，按钮工作，但 TabView 坏了。

任何想法如何让这个工作？

Answer 1

As a use case, think of sending "online" user status updates to the server in response to any user activity.

为全局手势识别器创建扩展:

extension UIApplication {
    func addGestureRecognizer() {
        guard let window = windows.first else { return }
        let gesture = UITapGestureRecognizer(target: window, action: nil)
        gesture.requiresExclusiveTouchType = false
        gesture.cancelsTouchesInView = false
        gesture.delegate = self
        window.addGestureRecognizer(gesture)
    }
}

extension UIApplication: UIGestureRecognizerDelegate {
    public func gestureRecognizer(_ gestureRecognizer: UIGestureRecognizer, shouldReceive touch: UITouch) -> Bool {
        print("touch detected")
        return true
    }

    public func gestureRecognizer(_ gestureRecognizer: UIGestureRecognizer, shouldRecognizeSimultaneouslyWith otherGestureRecognizer: UIGestureRecognizer) -> Bool {
        return true
    }
}

将其添加到根窗口:

SwiftUI 1 版本:

func scene(_ scene: UIScene, willConnectTo session: UISceneSession, options connectionOptions: UIScene.ConnectionOptions) {        
    // ...
    addGestureRecognizer()
}

SwiftUI 2 版本:

@main
struct TestApp: App {
    var body: some Scene {
        WindowGroup {
            ContentView()
                .onAppear(perform: UIApplication.shared.addGestureRecognizer)
        }
    }
}

现在手势识别器已附加到根窗口，并将与其他控件同时识别:

struct ContentView: View {
    var body: some View {
        TabView {
            Button("Tap me") {
                print("Button tapped")
            }
            .tabItem {
                Text("One")
            }
            List {
                Text("Hello")
                Text("World")
            }
            .tabItem {
                Text("Two")
            }
        }
    }
}

或者，您可以创建自定义 AnyGestureRecongizer建议 here检测任何手势。