The following code reproduced the error:
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
}
}
}
When sliding back from SecondView to ContentView but didn't complete the gesture, the app freezes. When deleting either @Environment or NavigationBarItem will fix this error.
For @Environment, it is needed for CoreData but used presentationMode for reproduction of error
adding ".navigationViewStyle(StackNavigationViewStyle())" to the NavigationView fix the problem for me. This is the code I use for testing this on real devices (iPhone, iPad) and various simulators. Using macos 10.15.5, Xcode 11.5 and 11.6 beta, target ios 13.5 and mac catalyst.
I have not tested this on all devices, so let me know if you find a device where this does not work.
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
}
}
}