SwiftUI：关闭工作表后导航栏按钮的点击目标未对齐

Question

I am noticing a rather strange, possibly buggy behavior in SwiftUI using iOS 13.3.1 and earlier. To demonstrate, this very simple scenario:

Full sample code:

import SwiftUI

struct ContentView: View {
    @State var showingSheet: Bool = false
    var body: some View {
        NavigationView {
            Text("ParentView")
                .navigationBarItems(trailing: Button(action: { self.showingSheet = true }) { Text("Show") })
        }.sheet(isPresented: $showingSheet) { SheetView() }
    }
}

struct SheetView: View {
    @Environment(\.presentationMode) var presentationMode
    var body: some View {
        VStack {
            Text("Sheet content")
            Button(action: { self.presentationMode.wrappedValue.dismiss() }) { Text("Hide") }
        }
    }
}

---

To reproduce:

1. Launch the app on iOS 13.4.1
2. Tap the "Show" button
3. (The sheet shows, as expected)
4. Dismiss the sheet using the "Hide" button
5. (The sheet is dismissed, as expected)
6. Try to show the sheet again, using the "Show" button

Expected result : The sheet shows again.

Actual result : The tap target of the "Show" button is shifted some pixels to the bottom, resulting in the action not triggering. This can also be observed in the View Hierarchy Debugger:

Other observations:

• This does not happen when dismissing the sheet by dragging it to the bottom of the screen
• This occurs only if large navigation item titles are activated for the hosting view, it's fine when using an inline title

---

So now I'm here wondering: Am I making a mistake, or is this an actual SwiftUI bug? If so, is there an easy workaround? I searched SO for similar issues, but didn't come across any that were identical.

Edit: I filed this with Apple as Radar Feedback FB7560960 in the meantime.

Edit 2: Still happening in 13.4.1.

Answer 1

我不知道为什么，但是将@Environment(\\.presentationMode) var presentationMode添加到contentView似乎可以解决它。

Answer 2

I had exactly the same issue, but funnily enough, was only able to reproduce it on some simulators/devices running iOS 14.4 and 15.0 - not on iOS 13.3.

The only workaround that solved it for me was to change the presentation mode from .automatic (ie .pageSheet on iOS >=13) to .fullScreen (the previous default). I suppose the equivalent in pure SwiftUI would be to use .fullScreenCover instead of .sheet .

Answer 3

iOS 16+

.sheet(isPresented: $showingSheet) {
  SheetView()
   .presentationDetents([.fraction(0.999)])
 }