FB13705098

Sheet background doesn't reach bottom when programmatically changing detent

Basic Information

Which platform is most relevant for your report?

iOS

Which technology does your report involve?

SwiftUI

What type of feedback are you reporting?

Incorrect/Unexpected Behavior

What build does the issue occur on?

iOS 17.4 Seed 3 (21E5200d)

Where does the issue occur?

On device

Description

• Run the given code.
• Make sure the sheet is presented.
• Press "Toggle detent" to toggle the sheet detent.
• When going from a larger detent to a shorter detent, the background of the sheet doesn't reach the bottom of the screen.
• Unexpectedly, we can see a gap during the animation. This gap should not exist.
• See the attached workaround, where extra padding is added to the bottom of the background.

Evidence

Visual

Demo	Workaround

Code

AppleFeedback/FB13705098/demo.swift

Lines 1 to 34 in da72930

	import SwiftUI
	struct ContentView: View {
	@State private var presented = true
	@State private var detent: PresentationDetent = .large
	var body: some View {
	Button("Present") {
	presented = true
	}
	.sheet(isPresented: $presented) {
	VStack {
	Button("Toggle detent") {
	if detent == .large {
	detent = .medium
	} else {
	detent = .large
	}
	}
	.padding(.top, 50)
	Spacer()
	}
	.presentationBackground {
	Color.red
	}
	.presentationDetents([.medium, .large], selection: $detent)
	}
	}
	}
	#Preview {
	ContentView()
	}

AppleFeedback/FB13705098/workaround.swift

Lines 1 to 35 in da72930

	import SwiftUI
	struct ContentView: View {
	@State private var presented = true
	@State private var detent: PresentationDetent = .large
	var body: some View {
	Button("Present") {
	presented = true
	}
	.sheet(isPresented: $presented) {
	VStack {
	Button("Toggle detent") {
	if detent == .large {
	detent = .medium
	} else {
	detent = .large
	}
	}
	.padding(.top, 50)
	Spacer()
	}
	.presentationBackground {
	Color.red
	.padding(.bottom, -1000)
	}
	.presentationDetents([.medium, .large], selection: $detent)
	}
	}
	}
	#Preview {
	ContentView()
	}