在 swiftui 中将数据传递给 .popover

Question

我有一个 String 值在按下按钮后会发生变化，我有一个 .popover 来显示它的值，但该值没有变化。我在每一步都添加了 print() 以清楚地表明该值已更改

我的ContentView.swift

import SwiftUI

struct ContentView: View {
    @State private var showingPopover = false
    @State private var popoverText = "hey, I'm the initial text"

    var body: some View {
        Button("press me!") {
            print("1) \(popoverText)")
            popoverText = "hey, I'm the new text"
            print("2) \(popoverText)")
            showingPopover = true
            print("3) \(popoverText)")
                }
                .popover(isPresented: $showingPopover) {
                    Text(popoverText)
                        .onAppear(perform: {print("4) \(popoverText)")})
                }
    }
}

按下按钮后打印出来：

1) hey, I'm the initial text
2) hey, I'm the new text
3) hey, I'm the new text
4) hey, I'm the new text

并显示：

虽然我找到了一个奇怪的解决方法。如果我添加 Text(popoverText):

一切正常

import SwiftUI

struct ContentView: View {
    @State private var showingPopover = false
    @State private var popoverText = "hey, I'm the initial text"

    var body: some View {
        VStack{
            Text(popoverText)
            Button("press me!") {
                print("1) \(popoverText)")
                popoverText = "hey, I'm the new text"
                print("2) \(popoverText)")
                showingPopover = true
                print("3) \(popoverText)")
                    }
            }
                .popover(isPresented: $showingPopover) {
                    Text(popoverText)
                        .onAppear(perform: {print("4) \(popoverText)")})
                }
    }
}

它打印同样的东西：

1) hey, I'm the initial text
2) hey, I'm the new text
3) hey, I'm the new text
4) hey, I'm the new text

但现在显示的是新文本：

我认为这与视图刷新或焦点有关，但我没有成功确定确切的事情

编辑：我的实际应用程序没有按钮，下面的代码只是作为示例，所以保持 .isPresented 是必要的，并且只允许使用 .isPresented 或 [=21] =]

Answer 1

.popover(item: someIdentifiableObj, content: ...) 用于将数据传递到 popover

struct HomeView: View {
    @State var userObj: User?

    var body: some View {
        Button("press me!") {
            userObj = User(popoverText: "New Text")
        }
        .popover(item: $userObj) { user in
            Text(user.popoverText)
        }
    }
}

// MARK: - PREVIEW

struct ContentView_Previews: PreviewProvider {
    static var previews: some View {
        HomeView()
    }
}

struct User: Identifiable {
    let id: UUID = UUID()
    let popoverText: String
}

在 swiftui 中将数据传递给 .popover

Passing data to .popover in swiftui

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swiftui