ios - 在 SwiftUI TabView 中禁用滑动手势

Question

尝试在 SwiftUI 中实现具有 PageTabView 样式的 TabView，其中导航仅以编程方式完成，并且禁用所有滑动手势。

This solution仅部分有效 - 如果您在选择发生变化时点击屏幕，它仍然会干扰过渡并导致奇怪的效果。此外，如果您用两根手指滚动，手势仍会记录下来。我需要一个完全禁用滑动手势的解决方案。

代码:

struct PageViewTest: View {
    @State var selection: Int = 1
    
    var body: some View {
        ZStack {
            Color.green.ignoresSafeArea()
            
            TabView(selection: $selection) {
                Color.red
                    .tag(1)
                    .gesture(DragGesture())
                
                Color.blue
                    .tag(2)
                    .gesture(DragGesture())
                
                Color.yellow
                    .tag(3)
                    .gesture(DragGesture())
            }
            .tabViewStyle(PageTabViewStyle(indexDisplayMode: .never))
            .animation(.linear, value: selection)
            
            VStack {
                Spacer()
                Button(action: {
                    selection = selection == 3 ? 1 : selection + 1
                }) {
                    Text("next")
                        .foregroundColor(.white)
                        .font(.title)
                }
            }
        }
    }
}

将 .disabled(true) 设置为 TabView 可以解决它，但是所有的 subview 都不再具有交互性。

Answer 1

This answer允许在 SwiftUI 中使用自定义手势识别器创建叠加层。然后我们需要做的就是创建一个不允许手势开始的委托(delegate)。

所以代码是:

import SwiftUI
import UIKit


struct ContentView: View {
    @State var selection: Int = 1
    let numTabs = 3
    let minDragTranslationForSwipe: CGFloat = 5000

    var body: some View {
        ZStack {
            Color.green.ignoresSafeArea()
            
            TabView(selection: $selection) {
                Color.red
                    .tag(1)
                Color.blue
                    .tag(2)
                Color.yellow
                    .tag(3)
            }
            .tabViewStyle(PageTabViewStyle(indexDisplayMode: .never))
            .animation(.linear, value: selection)
                .overlay(TouchesHandler())
            
            VStack {
                Spacer()
                Button(action: {
                    selection = selection == 3 ? 1 : selection + 1
                }) {
                    Text("next")
                        .foregroundColor(.white)
                        .font(.title)
                }
            }
        }

    }
}

//just a dummy
class MySwipeGesture: UISwipeGestureRecognizer {

    @objc func noop() {}

    init(target: Any?) {
        super.init(target: target, action: #selector(noop))
    }
}

//this delegate effectively disables the gesure
class MySwipeGestureDelegate: NSObject, UIGestureRecognizerDelegate {
    func gestureRecognizerShouldBegin(_ gestureRecognizer: UIGestureRecognizer) -> Bool {
        false
    }
}

//and the overlay inspired by the answer from the link above
struct TouchesHandler: UIViewRepresentable {

    func makeUIView(context: UIViewRepresentableContext<TouchesHandler>) -> UIView {
        let view = UIView(frame: .zero)
        view.isUserInteractionEnabled = true
        view.addGestureRecognizer(context.coordinator.makeGesture())
        return view;
    }

    func updateUIView(_ uiView: UIView, context: UIViewRepresentableContext<TouchesHandler>) {
    }

    func makeCoordinator() -> Coordinator {
        return Coordinator()
    }

    class Coordinator {
        var delegate: UIGestureRecognizerDelegate = MySwipeGestureDelegate()
        func makeGesture() -> MySwipeGesture {
            delegate = MySwipeGestureDelegate()
            let gr = MySwipeGesture(target: self)
            gr.delegate = delegate
            return gr
        }
    }
    typealias UIViewType = UIView
}