resizable header in SwiftUI - swiftui

Question

I was trying to make resizable header but it breaks.
I am trying to clone twitter profile,
I think logic is right but can I know why this one is not working?
I made HStack and try to hide it but when I scroll back it can't come back.
Tried with GeometryReader
Please help me, thanks
import SwiftUI
struct ProfileView: View {
// change views
#State var isHide = false
#State private var selectionFilter: TweetFilterViewModel = .tweets
#Namespace var animation
var body: some View {
VStack(alignment: .leading) {
//hiding
if isHide == false {
headerView
actionButtons
userInfoDetails
}
tweetFilterBar
.padding(0)
ScrollView(showsIndicators: false) {
LazyVStack {
GeometryReader { reader -> AnyView in
let yAxis = reader.frame(in: .global).minY
let height = UIScreen.main.bounds.height / 2
if yAxis < height && !isHide {
DispatchQueue.main.async {
withAnimation {
isHide = true
}
}
}
if yAxis > 0 && isHide {
DispatchQueue.main.async {
withAnimation {
isHide = false
}
}
}
return AnyView(
Text("")
.frame(width: 0, height: 0)
)
}
.frame(width: 0, height: 0)
ForEach(0...9, id: \.self) { _ in
TweetRowView()
}
}
}
Spacer()
}
}
}
struct ProfileView_Previews: PreviewProvider {
static var previews: some View {
ProfileView()
}
}
extension ProfileView {
var headerView: some View {
ZStack(alignment: .bottomLeading) {
Color(.systemBlue)
.ignoresSafeArea()
VStack {
Button {
} label: {
Image(systemName: "arrow.left")
.resizable()
.frame(width: 20, height: 16)
.foregroundColor(.white)
.position(x: 30, y: 12)
}
}
Circle()
.frame(width: 72, height: 72)
.offset(x: 16, y: 24)
}.frame(height: 96)
}
var actionButtons: some View {
HStack(spacing: 12){
Spacer()
Image(systemName: "bell.badge")
.font(.title3)
.padding(6)
.overlay(Circle().stroke(Color.gray, lineWidth: 0.75))
Button {
} label: {
Text("Edit Profile")
.font(.subheadline).bold()
.accentColor(.black)
.padding(10)
.overlay(RoundedRectangle(cornerRadius: 20).stroke(Color.gray, lineWidth: 0.75))
}
}
.padding(.trailing)
}
var userInfoDetails: some View {
VStack(alignment: .leading) {
HStack(spacing: 4) {
Text("Heath Legdet")
.font(.title2).bold()
Image(systemName: "checkmark.seal.fill")
.foregroundColor(Color(.systemBlue))
}
.padding(.bottom, 2)
Text("#joker")
.font(.subheadline)
.foregroundColor(.gray)
Text("Your mom`s favorite villain")
.font(.subheadline)
.padding(.vertical)
HStack(spacing: 24) {
Label("Gothem.NY", systemImage: "mappin.and.ellipse")
Label("www.thejoker.com", systemImage: "link")
}
.font(.caption)
.foregroundColor(.gray)
HStack(spacing: 24) {
HStack {
Text("807")
.font(.subheadline)
.bold()
Text("following")
.font(.caption)
.foregroundColor(.gray)
}
HStack {
Text("200")
.font(.subheadline)
.bold()
Text("followers")
.font(.caption)
.foregroundColor(.gray)
}
}
.padding(.vertical)
}
.padding(.horizontal)
}
var tweetFilterBar: some View {
HStack {
ForEach(TweetFilterViewModel.allCases, id: \.rawValue) { item in
VStack {
Text(item.title)
.font(.subheadline)
.fontWeight(selectionFilter == item ? .semibold : .regular)
.foregroundColor(selectionFilter == item ? .black : .gray)
ZStack {
Capsule()
.fill(Color(.clear))
.frame(height: 3)
if selectionFilter == item {
Capsule()
.fill(Color(.systemBlue))
.frame(height: 3)
.matchedGeometryEffect(id: "filter", in: animation)
}
}
}
.onTapGesture {
withAnimation(.easeInOut) {
self.selectionFilter = item
}
}
}
}
}
}

Answer 1

While the animation between show and hide is running, the GeometryReader is still calculating values – which lets the view jump between show and hide – and gridlock.
You can introduce a new #State var isInTransition = false that checks if a show/hide animation is in progress and check for that. You set it to true at the beginning of the animation and to false 0.5 secs later.
Also I believe the switch height is not exactly 1/2 of the screen size.
So add a new state var:
#State var isInTransition = false
and in GeometryReader add:
GeometryReader { reader -> AnyView in
let yAxis = reader.frame(in: .global).minY
let height = UIScreen.main.bounds.height / 2
if yAxis < 350 && !isHide && !isInTransition {
DispatchQueue.main.async {
isInTransition = true
withAnimation {
isHide = true
}
}
// wait for animation to finish
DispatchQueue.main.asyncAfter(deadline: .now() + 0.5) {
isInTransition = false
}
} else if yAxis > 0 && isHide && !isInTransition {
DispatchQueue.main.async {
isInTransition = true
withAnimation {
isHide = false
}
}
// wait for animation to finish
DispatchQueue.main.asyncAfter(deadline: .now() + 0.5) {
isInTransition = false
}
}
return AnyView(
// displaying values for test purpose
Text("\(yAxis) - \(isInTransition ? "true" : "false")").foregroundColor(.red)
// .frame(width: 0, height: 0)
)
}