在 SwiftUI 中，应用程序在中途滑回时没有任何警告地冻结但在完成之前释放

Question

以下代码重现了错误：

import SwiftUI

struct ContentView: View {
    @State private var number: Int = 5
    var body: some View {
        NavigationView() {
            VStack(spacing: 20) {
                NavigationLink(destination: SecondView(bottles: $number)) {
                    Text("Click me")
                }
            }
        }
    }
}

struct SecondView: View {
    @Environment(\.presentationMode) private var presentationMode: Binding<PresentationMode>
    @State private var color: UIColor = .black
    @Binding var bottles: Int

    var body: some View {
        Text("I have \(bottles) in my bag")
            .foregroundColor(Color(color))
            .navigationBarTitle(Text("Water Bottle"))
            .navigationBarItems(trailing:
                Button("Click") {
                    self.someFunction()
                }
        )
    }

    func someFunction() {
        if self.color == UIColor.black {
            self.color = .red
        } else {
            self.color = .black
        }
    }
}

当从SecondView 滑回ContentView 但未完成手势时，应用会卡住。删除 @Environment 或 NavigationBarItem 将修复此错误。

对于@Environment，CoreData 需要它，但使用 presentationMode 来重现错误

Answer 1

将“.navigationViewStyle(StackNavigationViewStyle())”添加到 NavigationView 为我解决了这个问题。这是我用于在真实设备（iPhone、iPad）和各种模拟器上进行测试的代码。使用 macos 10.15.5、Xcode 11.5 和 11.6 beta，目标 ios 13.5 和 mac 催化剂。

我尚未在所有设备上对此进行测试，所以如果您发现此功能不起作用的设备，请告诉我。

import SwiftUI

struct ContentView: View {
@State private var number: Int = 5
var body: some View {
    NavigationView() {
        VStack(spacing: 20) {
            NavigationLink(destination: SecondView(bottles: $number)) {
                Text("Click me")
            }
        }
    }.navigationViewStyle(StackNavigationViewStyle())  //  <---
}
}

struct SecondView: View {
@Environment(\.presentationMode) private var presentationMode: Binding<PresentationMode>
@State private var color: UIColor = .black
@Binding var bottles: Int

var body: some View {
    Text("I have \(bottles) in my bag")
        .foregroundColor(Color(color))
        .navigationBarTitle(Text("Water Bottle"))
        .navigationBarItems(trailing:
            Button("Click") {
                self.someFunction()
            }
    )
}

func someFunction() {
    if self.color == UIColor.black {
        self.color = .red
    } else {
        self.color = .black
    }
}
}

在 SwiftUI 中，应用程序在中途滑回时没有任何警告地冻结但在完成之前释放

In SwiftUI, the application freeze without any warning when slide back halfway but released before completion

ios

swift

swiftui

ios-navigationview

property-wrapper