TabView (SwiftUI):在已经激活的 tabItem 上响应 onTab [英] TabView (SwiftUI): Respond onTab on an already active tabItem

问题描述

我有一个包含 TabView 的 ContentView.swift.

I have a ContentView.swift which contains a TabView.

View1 中有一个带有一些子视图的 NavigationView.View2 只是一个 View.

View1 has a NavigationView in it with some childViews. View2 is just a single View.

我想在按下第一个 tabItem 时执行一些操作(总是返回到 View1，即使在 View1 的 childView 中).即使它已经是活动的tabItem.

I would like to perform some action (always return to View1, even when being in a childView of View1), when the first tabItem is pressed. Even if it is already the active tabItem.

我尝试了如下所示的 onTapGesture，它似乎没有任何作用.在.tag(0)"之前添加它也没有改变任何东西:

I tried onTapGesture as seen below, which didn't seem to do anything. Adding it right before ".tag(0)" didn't change anything, either:

                            TabView {
                            View1()
                                .onTapGesture {
                                    print("Test")
                            }
                                .tabItem {
                                    Image(systemName: "doc.plaintext")
                                        .font(.system(size: 25))
                                    Text("View1")
                            }.tag(0)

                            View2()
                                .tabItem {
                                    Image(systemName: "person.crop.circle")
                                        .font(.system(size: 25))
                                    Text("View2")
                            }.tag(1)

推荐答案

这是可能的方法.使用 Xcode 11.4/iOS 13.4 测试

Here is possible approach. Tested with Xcode 11.4 / iOS 13.4

struct TestTabSelectionAction: View {
    @State private var selectedTab = 0

    var body: some View {
        let selection = Binding<Int>(
            get: { self.selectedTab },
            set: { self.selectedTab = $0
                print("Pressed tab: ($0)")
                if $0 == 0 {
                           // <<< your action here !!
                }
        })

        return TabView(selection: selection) {
            View1()
            .tabItem {
                Image(systemName: "doc.plaintext")
                    .font(.system(size: 25))
                Text("View1")
            }.tag(0)

            View2()
                .tabItem {
                    Image(systemName: "person.crop.circle")
                        .font(.system(size: 25))
                    Text("View2")
            }.tag(1)
        }
    }
}

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