如何在 SwiftUI 中使 UIViewRepresentable 在 tvOS 上具有焦点？答案

【问题标题】：How to make UIViewRepresentable focusable on tvOS in SwiftUI?如何在 SwiftUI 中使 UIViewRepresentable 在 tvOS 上具有焦点？
【发布时间】：2020-04-23 18:12:40
【问题描述】：

标题说明了一切 - 我无法在 tvOS 上的 SwiftUI 中专注于 UIViewRepresentable。任何符合View 协议的视图都可以毫无问题地聚焦，但UIViewRepresentable 和UIViewControllerRepresentable 都不能。

有什么想法吗？

此代码有效：

struct ContentView: View {
    var body: some View {
        Text("Hello, World!")
            .focusable()
            .onExitCommand {
                print("Menu button pressed")
        }
    }
}

这个没有：

struct ContentView: View {
    var body: some View {
        ViewRepresentable()
            .focusable()
            .onExitCommand {
                print("Menu button pressed")
        }
    }
}

struct ViewRepresentable: UIViewRepresentable {
    func makeUIView(context: Context) -> UIView {
        let view = UIView()
        view.backgroundColor = .red

        return view
    }

    func updateUIView(_ uiView: UIView, context: Context) {

    }
}

谢谢！

【问题讨论】：

你有什么解决办法吗？我在尝试让 UISearchController 在 SwiftUI 应用程序中工作时遇到同样的问题
@GuyBrooker 这个有什么更新吗？与UISearchController 有同样的问题

标签： swiftui tvos apple-tv uiviewrepresentable

【解决方案1】：

您需要创建一个覆盖 canBecomeFocused 的 UIView 子类以返回 true。如果您想响应焦点，您可能还想覆盖 didUpdateFocus(in:with:)。

作为参考，我制作了一个实用程序类，让我拥有可聚焦的 UIView，并响应远程滑动和点击。

import UIKit

@available (iOS, unavailable)
@available (macCatalyst, unavailable)
class UserInputView: UIView {
    weak var pressDelegate: PressableDelegate?
    weak var touchDelegate: TouchableDelegate?
    var touchStarted: CGFloat = 0
    var lastTouch: CGFloat = 0
    
    override init(frame: CGRect) {
        super.init(frame: frame)
    }

    override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
        touchStarted = touches.first?.location(in: nil).x ?? 0
        lastTouch = touchStarted
        touchDelegate?.touchDown()
    }
    
    override func touchesMoved(_ touches: Set<UITouch>, with event: UIEvent?) {
        let thisTouch = touches.first?.location(in: nil).x ?? 0
        touchDelegate?.touchMove(amount: Double((thisTouch - lastTouch)/(touches.first?.window?.frame.width ?? 1920)))
        lastTouch = touches.first?.location(in: nil).x ?? 0
    }
    
    override func touchesEnded(_ touches: Set<UITouch>, with event: UIEvent?) {
        touchDelegate?.touchUp()
    }

    override func pressesBegan(_ presses: Set<UIPress>, with event: UIPressesEvent?) {
        if isClick(presses) {
            pressDelegate?.press(pressed: true)
        } else {
            superview?.pressesBegan(presses, with: event)
        }
    }
    
    override func pressesEnded(_ presses: Set<UIPress>, with event: UIPressesEvent?) {
        if isClick(presses) {
            pressDelegate?.press(pressed: false)
            pressDelegate?.clicked()
        } else {
            superview?.pressesEnded(presses, with: event)
        }
    }
    
    private func isClick(_ presses: Set<UIPress>?) -> Bool {
        return presses?.map({ $0.type }).contains(.select) ?? false
    }
    
    override func didUpdateFocus(in context: UIFocusUpdateContext, with coordinator: UIFocusAnimationCoordinator) {
        pressDelegate?.focus(focused: isFocused)
    }
    
    required init?(coder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }
    
    override var canBecomeFocused: Bool {
        return true
    }
}

【讨论】：