WkWebView has spacing appear after it in SwiftUI - swiftui

I am having a problem where a spacing appears after the content of my WKWebView (picture included at the very bottom). I am displaying a grouping of several live streams from Facebook, but this issue keeps showing up. I have not found any solutions on Stackoverflow or other websites. My webviews are being scaled to fit in the main view as well. This is all being done in SwiftUI also and I tried adding an offset but then this added a long empty space at the bottom of the view, as expected. I appreciate any possible help because I am not exactly sure the cause of this, and I am not sure if this is a Facebook issue or something I am doing. Thank you.
Here is the code in my main body view that displays the web views:
ScrollView {
HStack {
Text("Most Recent Livestream")
.font(.title)
.padding([.top, .leading])
Spacer()
}
VStack {
if (self.fb.showWebViews != false) {
fb.getwebView(index: 0).scaledToFit()
}
}
VStack {
if (self.fb.showWebViews != false) {
Text("\(fb.getVideoDate(index: 1))")
fb.getwebView(index: 1).scaledToFit()
}
}
VStack {
if (self.fb.showWebViews != false) {
Text("\(fb.getVideoDate(index: 2))")
fb.getwebView(index: 2).scaledToFit()
}
}
VStack {
if (self.fb.showWebViews != false) {
Text("\(fb.getVideoDate(index: 3))")
fb.getwebView(index: 3).scaledToFit()
}
}
VStack {
if (self.fb.showWebViews != false) {
Text("\(fb.getVideoDate(index: 4))")
fb.getwebView(index: 4).scaledToFit()
}
}
Button(action: {
print("LEARN MORE!")
}) {
Image(systemName: "questionmark.circle")
Text("Want to view more livestreams?")
.foregroundColor(Color(.label))
}.padding([.top, .leading])
Spacer()
}
Here is the webview code:
struct WebView2 : UIViewRepresentable {
// Instence Var of request URL
var request: URLRequest
// Creates the UIView of the WebView
func makeUIView(context: Context) -> WKWebView {
return WKWebView()
}
// Updates the Webview
/// With disable scrolling, backround becomes opaue, and reloads page with the quested URL
func updateUIView(_ uiView: WKWebView, context: Context) {
uiView.scrollView.isScrollEnabled = false
uiView.isOpaque = false
uiView.load(request)
}
}
Here is a picture of what it looks like with the spacing:

It turned out that in order to fix this problem all I had to do was remove the .scaledToFit() on each WebView in the VStacks. Then after removing those, I then had to put .frame(height: 233) on each WebView in the VStacks in order to make then all display completly, since they always will be 233 in height.

Related

LazyVStack in ScrollView has jittery auto scroll

I have a chat app, where whenever a chat room is opened, I need the view to scroll to the bottom as soon as the messages are fetched.
The thing is that although it does scroll perfectly when a new message is received or sent (see ViewModel down below), it is very jittery when I tell it to scroll right after the first batch of messages is fetched, which happens once as soon as the view appears.
After a lot of trial and error, I realized that if I add a small delay to the scroll, it'll improve but not completely! It is like it's trying to scroll to the very bottom, but it'll fail just for a few inches. I also realized that if I add a bigger delay, like 2 seconds, it'll scroll just fine.
Here's the messages list view:
struct MessagesView: View {
#StateObject private var viewModel = ViewModel()
// -----------------------
let currentChatRoom: ChatRoom
// -----------------------
var body: some View {
ZStack {
Color.black.ignoresSafeArea()
VStack {
ScrollView {
ScrollViewReader { proxy in
LazyVStack {
ForEach(viewModel.messages) { message in
MessageView(message: message)
.id(message.id)
.onTapGesture {
viewModel.shouldDismissKeyboard = true
}
}
}
.onChange(of: viewModel.shouldScrollToMessageId) { messageId in
if let messageId = messageId, !messageId.isEmpty {
proxy.scrollTo(messageId, anchor: .bottom)
}
}
}
}
VStack(alignment: .leading) {
if chatEnvironment.isOtherUserTyping {
TypingIndicationView()
}
BottomView()
.padding(.bottom, 4)
}
}
}
.onAppear {
viewModel.setUp(currentChatRoom: currentChatRoom)
}
}
}
As you can see, it’s viewModel.shouldScrollToMessageId that’s responsible for "auto-scrolling" to the last message.
Here’s MessageView:
fileprivate struct MessageView: View {
let message: Message
var body: some View {
HStack {
VStack(alignment: .leading, spacing: 1) {
Text(message.user.isCurrentUser == true ? "You" : "\(message.user.username)")
.foregroundColor(message.user.isCurrentUser == true ? .customGreen : .customBlue)
.multilineTextAlignment(.leading)
.font(.default(size: 16))
.padding(.bottom, 1)
if let imageURL = message.postSource?.imageURL, !imageURL.isEmpty {
VStack(alignment: .leading) {
WebImage(url: .init(string: imageURL))
.resizable()
.indicator(.activity)
.scaledToFill()
.frame(width: UIScreen.main.bounds.width / 2, height: UIScreen.main.bounds.width / 1.45)
.cornerRadius(25)
}
}
Text(message.text)
.foregroundColor(.white)
.multilineTextAlignment(.leading)
.font(.default(size: 16))
}
Spacer()
}
.padding(.bottom, 8)
.padding(.horizontal)
.background(
Color.black
)
}
}
Here’s the ViewModel:
class ViewModel: ObservableObject {
#Published var messages = [Message]()
#Published var text = ""
#Published var shouldScrollToMessageId: String?
#Published var currentChatRoom: ChatRoom?
// -----------------------------
private var isInitialized = false
// -----------------------------
func setUp(currentChatRoom: ChatRoom) {
guard !isInitialized else { return }
isInitialized.toggle()
// -----------------------------
self.currentChatRoom = currentChatRoom
// -----------------------------
getFirstBatchOfMessages(chatRoom: chatRoom)
subscribeToNewMessages()
}
private func getFirstBatchOfMessages(chatRoom: ChatRoom) {
messagesService.getMessages(chatRoomId: chatRoom.id) { [weak self] messages in
DispatchQueue.main.async {
self?.messages = messages
}
self?.scrollToBottom(delay: 0.15)
}
}
private func subscribeToNewMessages() {
...
if !newMessages.isEmpty {
self?.scrollToBottom(delay: 0)
}
}
func scrollToBottom(delay: TimeInterval) {
DispatchQueue.main.async {
self.shouldScrollToMessageId = self.messages.last?.id
}
}
func sendMessage() {
...
scrollToBottom(delay: 0)
}
}
Here, scrollToBottom is responsible for notifying the MessagesView that shouldScrollToMessageId's value changed and that it should scroll to the last message.
Any help will be much appreciated!!!
I am also writing an application with a chat on SwiftUI and I also have a lot of headaches with a bunch of ScrollView and LazyVStack.
In my case, I load messages from the CoreData and display them in a LazyVStack, so in my case, scrolling to the last message does not work, it seems to me simply because a bottom last view did not render, because rendering starts from the top.
Therefore, I came up with a solution with placing an invisible view at the bottom and assigned it a static ID, in my case -1:
VStack(spacing: 0) {
LazyVStack(spacing: 0) {
ForEach(messages) { message in
MessageRowView(viewWidth: wholeViewProxy.size.width, message: message)
.equatable()
}
}
Color.clear.id(-1)
.padding(.bottom, inputViewHeight)
}
I call scroll to this view:
.onAppear {
scrollTo(messageID: -1, animation: nil, scrollReader: scrollReader)
}
And it works... but sometimes...
Sometimes it works correctly, sometimes it stops without scrolling a couple of screens to the end. Looks like LazyVStack is rendering the next views after the scrollTo has finished its work. Also, if add scrolling with some delay it may works better, but not always perfect.
I hope this can be a little helpful and if you find a stable solution I will be very happy if you share :)

How to add conditional ToolbarItems to NavigationView Toolbar with SwiftUI?

I am trying to add an icon button to the leading edge of a NavigationView's toolbar - but I want that button to only be visible when the device is in landscape mode. (Kinda like how the default Notes app works)
I have the following code:
var body: some View {
VStack {
// ... content display
}
.toolbar {
if UIDevice.current.orientation.isLandscape {
ToolbarItem(placement: .navigationBarLeading) {
Button(action: toggleFullscreen) {
if isFullscreen {
Image(systemName: "arrow.down.right.and.arrow.up.left")
} else {
Image(systemName: "arrow.up.left.and.arrow.down.right")
}
}
}
}
ToolbarItem(placement: .navigationBarTrailing) {
Button(action: createNewNote) {
Image(systemName: "square.and.pencil")
}
}
})
}
If I remove the conditional if clause within the toolbar content, it works fine, but it seems to not recognize the if statement at all?
However, the if statement in the VStack works fine.
The specific error I get is:
Closure containing control flow statement cannot be used with result builder 'ToolbarContentBuilder'
Any idea how to fix this?
P.S. Consider me a complete SwiftUI noob. Although, I am proficient in React - so any React analogies to help me understand would be much appreciated.
You're detecting the device orientation in a wrong way SwiftUI One way you can achieve that is by using a custom modifier to detect device rotation:
Cfr: https://www.hackingwithswift.com/quick-start/swiftui/how-to-detect-device-rotation
The code would look like this:
1. Create custom modifier: Detecting Device Rotation
// Our custom view modifier to track rotation and call our action
struct DeviceRotationViewModifier: ViewModifier {
let action: (UIDeviceOrientation) -> Void
func body(content: Content) -> some View {
content
.onAppear()
.onReceive(NotificationCenter.default.publisher(for: UIDevice.orientationDidChangeNotification)) { _ in
action(UIDevice.current.orientation)
}
}
}
// A View wrapper to make the modifier easier to use
extension View {
func onRotate(perform action: #escaping (UIDeviceOrientation) -> Void) -> some View {
self.modifier(DeviceRotationViewModifier(action: action))
}
}
2. Use the created modifier:
struct ContentView: View {
#State private var isFullscreen = false
#State private var orientation = UIDeviceOrientation.unknown
var body: some View {
NavigationView {
VStack {
// ... content display
}
.onRotate { orientation = $0 }
.toolbar {
ToolbarItem(placement: .navigationBarLeading) {
if orientation.isLandscape {
Button(action: {}) {
if isFullscreen {
Image(systemName: "arrow.down.right.and.arrow.up.left")
} else {
Image(systemName: "arrow.up.left.and.arrow.down.right")
}
}
}
}
ToolbarItem(placement: .navigationBarTrailing) {
Button(action: {}) {
Image(systemName: "square.and.pencil")
}
}
}
}
}
}

SwiftUI How To Hide The Navigation Bar While Keeping The Back Button

So I'm trying to hide the navigationBar in a Details view in SwiftUI. I've technically gotten it to work by using an init() in a different view, but the issue is that it's making the navigationBar transparent for the whole app, which I only want it in one view. The reason I haven't used an init() in the DetailsView is because I have a variable that needs an input, so I wasn't sure how to do that! Here is the code for the initializer:
init() {
let navBarAppearance = UINavigationBar.appearance()
navBarAppearance.backgroundColor = .clear
navBarAppearance.barTintColor = .clear
navBarAppearance.tintColor = .black
navBarAppearance.setBackgroundImage(UIImage(), for: .default)
navBarAppearance.shadowImage = UIImage()
}
Here's What The Content View and Details View code is like with the init() inside the detailsView:
// ContentView //
struct ContentView: View {
var body: some View {
NavigationView {
List {
ForEach(0..<5) { i in
NavigationLink(destination: DetailsView(test: 1)) {
Text("DetailsView \(i)")
}
}
}
.listStyle(InsetGroupedListStyle())
.navigationBarTitle("Test App")
}
}
}
// DetailsView //
struct DetailsView: View {
var test: Int
var body: some View {
ScrollView {
Text("More Cool \(test)")
Text("Cool \(test)")
Text("Less Cool \(test)")
}
}
init(test: Int) {
self.test = 8
let navBarAppearance = UINavigationBar.appearance()
navBarAppearance.backgroundColor = .clear
navBarAppearance.barTintColor = .clear
navBarAppearance.tintColor = .black
navBarAppearance.setBackgroundImage(UIImage(), for: .default)
navBarAppearance.shadowImage = UIImage()
}
}
struct DetailsView_Previews: PreviewProvider {
static var previews: some View {
DetailsView(test: 8)
}
}
It's a heavily edited version of my code, but it shows the problem I have. With no variables needing to be passed in, the init() worked to remove the bar in only that view. However, with that variable input, not only does it change all the views to the "8" for the number, but it also doesn't even hide the navigationBar. I'm not sure if I'm just doing something wrong nor if this is even the right way to do it, but any help would be appreciated!
Also, on a side note, does anyone know how to hide the statusBar in iOS 14 with the NavigationView?
I think you try to use UIKit logic instead of the SwiftUI one. This is what I would do to hide the navigation bar with a back button on the top leading side of your view.
As for hiding the status bar, I would use .statusBar(hidden: true).
But it seems not to work on iOS14. It may be a bug... You can refer yourself to the Apple documentation on this topic.
struct DetailsView: View {
#Environment(\.presentationMode) var presentation
var test: Int
var body: some View {
ZStack(alignment: .topLeading) {
ScrollView {
Text("More Cool \(test)")
Text("Cool \(test)")
Text("Less Cool \(test)")
}
Button(action: { presentation.wrappedValue.dismiss() }) {
HStack {
Image(systemName: "chevron.left")
.foregroundColor(.blue)
.imageScale(.large)
Text("Back")
.font(.title3)
.foregroundColor(.blue)
}
}
.padding(.leading)
.padding(.top)
}
.navigationTitle(Text(""))
.navigationBarHidden(true)
.statusBar(hidden: true)
}
}

Programatically scroll to SwiftUI list position? [duplicate]

It looks like in current tools/system, just released Xcode 11.4 / iOS 13.4, there will be no SwiftUI-native support for "scroll-to" feature in List. So even if they, Apple, will provide it in next major released, I will need backward support for iOS 13.x.
So how would I do it in most simple & light way?
scroll List to end
scroll List to top
and others
(I don't like wrapping full UITableView infrastructure into UIViewRepresentable/UIViewControllerRepresentable as was proposed earlier on SO).
SWIFTUI 2.0
Here is possible alternate solution in Xcode 12 / iOS 14 (SwiftUI 2.0) that can be used in same scenario when controls for scrolling is outside of scrolling area (because SwiftUI2 ScrollViewReader can be used only inside ScrollView)
Note: Row content design is out of consideration scope
Tested with Xcode 12b / iOS 14
class ScrollToModel: ObservableObject {
enum Action {
case end
case top
}
#Published var direction: Action? = nil
}
struct ContentView: View {
#StateObject var vm = ScrollToModel()
let items = (0..<200).map { $0 }
var body: some View {
VStack {
HStack {
Button(action: { vm.direction = .top }) { // < here
Image(systemName: "arrow.up.to.line")
.padding(.horizontal)
}
Button(action: { vm.direction = .end }) { // << here
Image(systemName: "arrow.down.to.line")
.padding(.horizontal)
}
}
Divider()
ScrollViewReader { sp in
ScrollView {
LazyVStack {
ForEach(items, id: \.self) { item in
VStack(alignment: .leading) {
Text("Item \(item)").id(item)
Divider()
}.frame(maxWidth: .infinity).padding(.horizontal)
}
}.onReceive(vm.$direction) { action in
guard !items.isEmpty else { return }
withAnimation {
switch action {
case .top:
sp.scrollTo(items.first!, anchor: .top)
case .end:
sp.scrollTo(items.last!, anchor: .bottom)
default:
return
}
}
}
}
}
}
}
}
SWIFTUI 1.0+
Here is simplified variant of approach that works, looks appropriate, and takes a couple of screens code.
Tested with Xcode 11.2+ / iOS 13.2+ (also with Xcode 12b / iOS 14)
Demo of usage:
struct ContentView: View {
private let scrollingProxy = ListScrollingProxy() // proxy helper
var body: some View {
VStack {
HStack {
Button(action: { self.scrollingProxy.scrollTo(.top) }) { // < here
Image(systemName: "arrow.up.to.line")
.padding(.horizontal)
}
Button(action: { self.scrollingProxy.scrollTo(.end) }) { // << here
Image(systemName: "arrow.down.to.line")
.padding(.horizontal)
}
}
Divider()
List {
ForEach(0 ..< 200) { i in
Text("Item \(i)")
.background(
ListScrollingHelper(proxy: self.scrollingProxy) // injection
)
}
}
}
}
}
Solution:
Light view representable being injected into List gives access to UIKit's view hierarchy. As List reuses rows there are no more values then fit rows into screen.
struct ListScrollingHelper: UIViewRepresentable {
let proxy: ListScrollingProxy // reference type
func makeUIView(context: Context) -> UIView {
return UIView() // managed by SwiftUI, no overloads
}
func updateUIView(_ uiView: UIView, context: Context) {
proxy.catchScrollView(for: uiView) // here UIView is in view hierarchy
}
}
Simple proxy that finds enclosing UIScrollView (needed to do once) and then redirects needed "scroll-to" actions to that stored scrollview
class ListScrollingProxy {
enum Action {
case end
case top
case point(point: CGPoint) // << bonus !!
}
private var scrollView: UIScrollView?
func catchScrollView(for view: UIView) {
if nil == scrollView {
scrollView = view.enclosingScrollView()
}
}
func scrollTo(_ action: Action) {
if let scroller = scrollView {
var rect = CGRect(origin: .zero, size: CGSize(width: 1, height: 1))
switch action {
case .end:
rect.origin.y = scroller.contentSize.height +
scroller.contentInset.bottom + scroller.contentInset.top - 1
case .point(let point):
rect.origin.y = point.y
default: {
// default goes to top
}()
}
scroller.scrollRectToVisible(rect, animated: true)
}
}
}
extension UIView {
func enclosingScrollView() -> UIScrollView? {
var next: UIView? = self
repeat {
next = next?.superview
if let scrollview = next as? UIScrollView {
return scrollview
}
} while next != nil
return nil
}
}
Just scroll to the id:
scrollView.scrollTo(ROW-ID)
Since SwiftUI structured designed Data-Driven, You should know all of your items IDs. So you can scroll to any id with ScrollViewReader from iOS 14 and with Xcode 12
struct ContentView: View {
let items = (1...100)
var body: some View {
ScrollViewReader { scrollProxy in
ScrollView {
ForEach(items, id: \.self) { Text("\($0)"); Divider() }
}
HStack {
Button("First!") { withAnimation { scrollProxy.scrollTo(items.first!) } }
Button("Any!") { withAnimation { scrollProxy.scrollTo(50) } }
Button("Last!") { withAnimation { scrollProxy.scrollTo(items.last!) } }
}
}
}
}
Note that ScrollViewReader should support all scrollable content, but now it only supports ScrollView
Preview
Preferred way
This answer is getting more attention, but I should state that the ScrollViewReader is the right way to do this. The introspect way is only if the reader/proxy doesn't work for you, because of a version restrictions.
ScrollViewReader { proxy in
ScrollView(.vertical) {
TopView().id("TopConstant")
...
MiddleView().id("MiddleConstant")
...
Button("Go to top") {
proxy.scrollTo("TopConstant", anchor: .top)
}
.id("BottomConstant")
}
.onAppear{
proxy.scrollTo("MiddleConstant")
}
.onChange(of: viewModel.someProperty) { _ in
proxy.scrollTo("BottomConstant")
}
}
The strings should be defined in one place, outside of the body property.
Legacy answer
Here is a simple solution that works on iOS13&14:
Using Introspect.
My case was for initial scroll position.
ScrollView(.vertical, showsIndicators: false, content: {
...
})
.introspectScrollView(customize: { scrollView in
scrollView.scrollRectToVisible(CGRect(x: 0, y: offset, width: 100, height: 300), animated: false)
})
If needed the height may be calculated from the screen size or the element itself.
This solution is for Vertical scroll. For horizontal you should specify x and leave y as 0
Thanks Asperi, great tip. I needed to have a List scroll up when new entries where added outside the view. Reworked to suit macOS.
I took the state/proxy variable to an environmental object and used this outside the view to force the scroll. I found I had to update it twice, the 2nd time with a .5sec delay to get the best result. The first update prevents the view from scrolling back to the top as the row is added. The 2nd update scrolls to the last row. I'm a novice and this is my first stackoverflow post :o
Updated for MacOS:
struct ListScrollingHelper: NSViewRepresentable {
let proxy: ListScrollingProxy // reference type
func makeNSView(context: Context) -> NSView {
return NSView() // managed by SwiftUI, no overloads
}
func updateNSView(_ nsView: NSView, context: Context) {
proxy.catchScrollView(for: nsView) // here NSView is in view hierarchy
}
}
class ListScrollingProxy {
//updated for mac osx
enum Action {
case end
case top
case point(point: CGPoint) // << bonus !!
}
private var scrollView: NSScrollView?
func catchScrollView(for view: NSView) {
//if nil == scrollView { //unB - seems to lose original view when list is emptied
scrollView = view.enclosingScrollView()
//}
}
func scrollTo(_ action: Action) {
if let scroller = scrollView {
var rect = CGRect(origin: .zero, size: CGSize(width: 1, height: 1))
switch action {
case .end:
rect.origin.y = scroller.contentView.frame.minY
if let documentHeight = scroller.documentView?.frame.height {
rect.origin.y = documentHeight - scroller.contentSize.height
}
case .point(let point):
rect.origin.y = point.y
default: {
// default goes to top
}()
}
//tried animations without success :(
scroller.contentView.scroll(to: NSPoint(x: rect.minX, y: rect.minY))
scroller.reflectScrolledClipView(scroller.contentView)
}
}
}
extension NSView {
func enclosingScrollView() -> NSScrollView? {
var next: NSView? = self
repeat {
next = next?.superview
if let scrollview = next as? NSScrollView {
return scrollview
}
} while next != nil
return nil
}
}
my two cents for deleting and repositioning list at any point based on other logic.. i.e. after delete/update, for example going to top.
(this is a ultra-reduced sample, I used this code after network call back to reposition: after network call I change previousIndex )
struct ContentView: View {
#State private var previousIndex : Int? = nil
#State private var items = Array(0...100)
func removeRows(at offsets: IndexSet) {
items.remove(atOffsets: offsets)
self.previousIndex = offsets.first
}
var body: some View {
ScrollViewReader { (proxy: ScrollViewProxy) in
List{
ForEach(items, id: \.self) { Text("\($0)")
}.onDelete(perform: removeRows)
}.onChange(of: previousIndex) { (e: Equatable) in
proxy.scrollTo(previousIndex!-4, anchor: .top)
//proxy.scrollTo(0, anchor: .top) // will display 1st cell
}
}
}
}
This can now be simplified with all new ScrollViewProxy in Xcode 12, like so:
struct ContentView: View {
let itemCount: Int = 100
var body: some View {
ScrollViewReader { value in
VStack {
Button("Scroll to top") {
value.scrollTo(0)
}
Button("Scroll to buttom") {
value.scrollTo(itemCount-1)
}
ScrollView {
LazyVStack {
ForEach(0 ..< itemCount) { i in
Text("Item \(i)")
.frame(height: 50)
.id(i)
}
}
}
}
}
}
}
MacOS 11: In case you need to scroll a list based on input outside the view hierarchy. I have followed the original scroll proxy pattern using the new scrollViewReader:
struct ScrollingHelperInjection: NSViewRepresentable {
let proxy: ScrollViewProxy
let helper: ScrollingHelper
func makeNSView(context: Context) -> NSView {
return NSView()
}
func updateNSView(_ nsView: NSView, context: Context) {
helper.catchProxy(for: proxy)
}
}
final class ScrollingHelper {
//updated for mac os v11
private var proxy: ScrollViewProxy?
func catchProxy(for proxy: ScrollViewProxy) {
self.proxy = proxy
}
func scrollTo(_ point: Int) {
if let scroller = proxy {
withAnimation() {
scroller.scrollTo(point)
}
} else {
//problem
}
}
}
Environmental object:
#Published var scrollingHelper = ScrollingHelper()
In the view: ScrollViewReader { reader in .....
Injection in the view:
.background(ScrollingHelperInjection(proxy: reader, helper: scrollingHelper)
Usage outside the view hierarchy: scrollingHelper.scrollTo(3)
As mentioned in #lachezar-todorov's answer Introspect is a nice library to access UIKit elements in SwiftUI. But be aware that the block you use for accessing UIKit elements are being called multiple times. This can really mess up your app state. In my cas CPU usage was going %100 and app was getting unresponsive. I had to use some pre conditions to avoid it.
ScrollView() {
...
}.introspectScrollView { scrollView in
if aPreCondition {
//Your scrolling logic
}
}
Another cool way is to just use namespace wrappers:
A dynamic property type that allows access to a namespace defined by the persistent identity of the object containing the property (e.g. a view).
struct ContentView: View {
#Namespace private var topID
#Namespace private var bottomID
let items = (0..<100).map { $0 }
var body: some View {
ScrollView {
ScrollViewReader { proxy in
Section {
LazyVStack {
ForEach(items.indices, id: \.self) { index in
Text("Item \(items[index])")
.foregroundColor(.black)
.frame(maxWidth: .infinity, alignment: .leading)
.padding()
.background(Color.green.cornerRadius(16))
}
}
} header: {
HStack {
Text("header")
Spacer()
Button(action: {
withAnimation {
proxy.scrollTo(bottomID)
}
}
) {
Image(systemName: "arrow.down.to.line")
.padding(.horizontal)
}
}
.padding(.vertical)
.id(topID)
} footer: {
HStack {
Text("Footer")
Spacer()
Button(action: {
withAnimation {
proxy.scrollTo(topID) }
}
) {
Image(systemName: "arrow.up.to.line")
.padding(.horizontal)
}
}
.padding(.vertical)
.id(bottomID)
}
.padding()
}
}
.foregroundColor(.white)
.background(.black)
}
}
Two parts:
Wrap the List (or ScrollView) with ScrollViewReader
Use the scrollViewProxy (that comes from ScrollViewReader) to scroll to an id of an element in the List. You can seemingly use EmptyView().
The example below uses a notification for simplicity (use a function if you can instead!).
ScrollViewReader { scrollViewProxy in
List {
EmptyView().id("top")
}
.onReceive(NotificationCenter.default.publisher(for: .ScrollToTop)) { _ in
// when using an anchor of `.top`, it failed to go all the way to the top
// so here we add an extra -50 so it goes to the top
scrollViewProxy.scrollTo("top", anchor: UnitPoint(x: 0, y: -50))
}
}
extension Notification.Name {
static let ScrollToTop = Notification.Name("ScrollToTop")
}
NotificationCenter.default.post(name: .ScrollToTop, object: nil)

Putting an Image() from url inside an HStack inside of Button inside of List makes it go black

I've been trying to make a List of buttons, and when it gets clicked, it calls some code, I also need some 'thumbnails' to go along with every button, so I made a HStack for each button and put it all on a List, now the thumbnail doesn't render, BTW, it renders system images and local assets just fine, it's just the images grabbed from the network
you can just copy-paste this into ContentView.swift to reproduce it
import SwiftUI
func artwork() -> Image
{
let art = "https://via.placeholder.com/150"
if let url = URL(string: art), let data = try? Data(contentsOf: url), let image = UIImage(data: data)
{
return Image(uiImage: image)
}
else
{
return Image(systemName: "book")
}
}
struct ContentView: View
{
var body: some View
{
List
{
Button(action: {...my code...})
{
HStack
{
artwork()
}
... some other info
}
}
}
}
This issue is similar to Avoid button styling its content in SwiftUI
You just have to add .renderingMode(.original) to your Image like so:
func artwork() -> Image
{
let art = "https://via.placeholder.com/150"
if let url = URL(string: art), let data = try? Data(contentsOf: url), let image = UIImage(data: data)
{
return Image(uiImage: image)
}
else
{
return Image(systemName: "book")
}
}
struct ContentView: View
{
var body: some View
{
List
{
Button(action: {})
{
HStack
{
artwork().renderingMode(.original)
}
}
}
}
}