SwiftUI NavigationLink 立即加载目标视图，无需单击 [英] SwiftUI NavigationLink loads destination view immediately, without clicking

问题描述

使用以下代码:

struct HomeView: View {
    var body: some View {
        NavigationView {
            List(dataTypes) { dataType in
                NavigationLink(destination: AnotherView()) {
                    HomeViewRow(dataType: dataType)
                }
            }
        }
    }
}

奇怪的是，当HomeView 出现时，NavigationLink 立即加载AnotherView.结果，所有 AnotherView 依赖项也被加载，即使它在屏幕上还不可见.用户必须单击该行才能使其出现.我的 AnotherView 包含一个 DataSource，在那里发生各种事情.问题是此时加载了整个 DataSource，包括一些计时器等.

What's weird, when HomeView appears, NavigationLink immediately loads the AnotherView. As a result, all AnotherView dependencies are loaded as well, even though it's not visible on the screen yet. The user has to click on the row to make it appear. My AnotherView contains a DataSource, where various things happen. The issue is that whole DataSource is loaded at this point, including some timers etc.

我做错了什么..?如何以这种方式处理它，一旦用户按下 HomeViewRow 就会加载 AnotherView?

Am I doing something wrong..? How to handle it in such way, that AnotherView gets loaded once the user presses on that HomeViewRow?

推荐答案

我发现解决此问题的最佳方法是使用 Lazy View.

The best way I have found to combat this issue is by using a Lazy View.

struct NavigationLazyView<Content: View>: View {
    let build: () -> Content
    init(_ build: @autoclosure @escaping () -> Content) {
        self.build = build
    }
    var body: Content {
        build()
    }
}

那么 NavigationLink 将如下所示.您可以将要显示的视图放在 ()

Then the NavigationLink would look like this. You would place the View you want to be displayed inside ()

NavigationLink(destination: NavigationLazyView(DetailView(data: DataModel))) { Text("Item") }

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