Showing 'UIActivityViewController' in SwiftUI - xcode

I want to let the user to be able to share a location but I don't know how to show UIActivityViewController in SwiftUI.

The basic implementation of UIActivityViewController in SwiftUI is
import UIKit
import SwiftUI
struct ActivityViewController: UIViewControllerRepresentable {
var activityItems: [Any]
var applicationActivities: [UIActivity]? = nil
func makeUIViewController(context: UIViewControllerRepresentableContext<ActivityViewController>) -> UIActivityViewController {
let controller = UIActivityViewController(activityItems: activityItems, applicationActivities: applicationActivities)
return controller
}
func updateUIViewController(_ uiViewController: UIActivityViewController, context: UIViewControllerRepresentableContext<ActivityViewController>) {}
}
And here is how to use it.
struct MyView: View {
#State private var isSharePresented: Bool = false
var body: some View {
Button("Share app") {
self.isSharePresented = true
}
.sheet(isPresented: $isSharePresented, onDismiss: {
print("Dismiss")
}, content: {
ActivityViewController(activityItems: [URL(string: "https://www.apple.com")!])
})
}
}

Based on Tikhonov's, the following code added a fix to make sure the activity sheet is dismissed properly (if not subsequently the sheet will not be presented).
struct ActivityViewController: UIViewControllerRepresentable {
var activityItems: [Any]
var applicationActivities: [UIActivity]? = nil
#Environment(\.presentationMode) var presentationMode
func makeUIViewController(context: UIViewControllerRepresentableContext<ActivityViewController>) -> UIActivityViewController {
let controller = UIActivityViewController(activityItems: activityItems, applicationActivities: applicationActivities)
controller.completionWithItemsHandler = { (activityType, completed, returnedItems, error) in
self.presentationMode.wrappedValue.dismiss()
}
return controller
}
func updateUIViewController(_ uiViewController: UIActivityViewController, context: UIViewControllerRepresentableContext<ActivityViewController>) {}
}

It's a one time thing currently. .sheet will show it as a sheet, but bringing it up again from the same view will have stale data. Those subsequent shows of the sheet will also not trigger any completion handlers. Basically, makeUIViewController is called only once which is the only way to get the data to share into the UIActivityViewController. updateUIViewController has no way to update the data in your activityItems or reset the controller because those are not visible from an instance of UIActivityViewController.
Note that it doesn't work with UIActivityItemSource or UIActivityItemProvider either. Using those is even worse. The placeholder value doesn't show.
I hacked around some more and decided that maybe the problem with my solution was a sheet that was presenting another sheet, and when one went away then the other stayed.
This indirect way of having a ViewController do the presentation when it appears made it work for me.
class UIActivityViewControllerHost: UIViewController {
var message = ""
var completionWithItemsHandler: UIActivityViewController.CompletionWithItemsHandler? = nil
override func viewDidAppear(_ animated: Bool) {
share()
}
func share() {
// set up activity view controller
let textToShare = [ message ]
let activityViewController = UIActivityViewController(activityItems: textToShare, applicationActivities: nil)
activityViewController.completionWithItemsHandler = completionWithItemsHandler
activityViewController.popoverPresentationController?.sourceView = self.view // so that iPads won't crash
// present the view controller
self.present(activityViewController, animated: true, completion: nil)
}
}
struct ActivityViewController: UIViewControllerRepresentable {
#Binding var text: String
#Binding var showing: Bool
func makeUIViewController(context: Context) -> UIActivityViewControllerHost {
// Create the host and setup the conditions for destroying it
let result = UIActivityViewControllerHost()
result.completionWithItemsHandler = { (activityType, completed, returnedItems, error) in
// To indicate to the hosting view this should be "dismissed"
self.showing = false
}
return result
}
func updateUIViewController(_ uiViewController: UIActivityViewControllerHost, context: Context) {
// Update the text in the hosting controller
uiViewController.message = text
}
}
struct ContentView: View {
#State private var showSheet = false
#State private var message = "a message"
var body: some View {
VStack {
TextField("what to share", text: $message)
Button("Hello World") {
self.showSheet = true
}
if showSheet {
ActivityViewController(text: $message, showing: $showSheet)
.frame(width: 0, height: 0)
}
Spacer()
}
.padding()
}
}

May be its not recommended, but it is really easy and two line of code (was for iPhone) to share text
Button(action: {
let shareActivity = UIActivityViewController(activityItems: ["Text To Share"], applicationActivities: nil)
if let vc = UIApplication.shared.windows.first?.rootViewController{
shareActivity.popoverPresentationController?.sourceView = vc.view
//Setup share activity position on screen on bottom center
shareActivity.popoverPresentationController?.sourceRect = CGRect(x: UIScreen.main.bounds.width / 2, y: UIScreen.main.bounds.height, width: 0, height: 0)
shareActivity.popoverPresentationController?.permittedArrowDirections = UIPopoverArrowDirection.down
vc.present(shareActivity, animated: true, completion: nil)
}
}) {
Text("Share")
}
EDIT: Now works fine on iPad (tested on iPad Pro (9.7 -inch) Simulator)

I want to suggest another implementation that looks more native (half screen height without white gap bottom).
import SwiftUI
struct ActivityView: UIViewControllerRepresentable {
var activityItems: [Any]
var applicationActivities: [UIActivity]? = nil
#Binding var isPresented: Bool
func makeUIViewController(context: Context) -> ActivityViewWrapper {
ActivityViewWrapper(activityItems: activityItems, applicationActivities: applicationActivities, isPresented: $isPresented)
}
func updateUIViewController(_ uiViewController: ActivityViewWrapper, context: Context) {
uiViewController.isPresented = $isPresented
uiViewController.updateState()
}
}
class ActivityViewWrapper: UIViewController {
var activityItems: [Any]
var applicationActivities: [UIActivity]?
var isPresented: Binding<Bool>
init(activityItems: [Any], applicationActivities: [UIActivity]? = nil, isPresented: Binding<Bool>) {
self.activityItems = activityItems
self.applicationActivities = applicationActivities
self.isPresented = isPresented
super.init(nibName: nil, bundle: nil)
}
required init?(coder: NSCoder) {
fatalError("init(coder:) has not been implemented")
}
override func didMove(toParent parent: UIViewController?) {
super.didMove(toParent: parent)
updateState()
}
fileprivate func updateState() {
guard parent != nil else {return}
let isActivityPresented = presentedViewController != nil
if isActivityPresented != isPresented.wrappedValue {
if !isActivityPresented {
let controller = UIActivityViewController(activityItems: activityItems, applicationActivities: applicationActivities)
controller.completionWithItemsHandler = { (activityType, completed, _, _) in
self.isPresented.wrappedValue = false
}
present(controller, animated: true, completion: nil)
}
else {
self.presentedViewController?.dismiss(animated: true, completion: nil)
}
}
}
}
struct ActivityViewTest: View {
#State private var isActivityPresented = false
var body: some View {
Button("Preset") {
self.isActivityPresented = true
}.background(ActivityView(activityItems: ["Hello, World"], isPresented: $isActivityPresented))
}
}
struct ActivityView_Previews: PreviewProvider {
static var previews: some View {
ActivityViewTest()
}
}

I got it to work now using
.sheet(isPresented: $isSheet, content: { ActivityViewController() }
.presentation is deprecated
It takes up the whole screen iOS 13 style.

If you need more granular control over the content displayed in the share sheet, you will probably end implementing UIActivityItemSource.
I tried using Mike W.'s code above but it didn't work at first (the delegate functions weren't being called). The fix was changing the initialisation of UIActivityController within makeUIViewController as follows, now passing [context.coordinator] as activityItems:
let controller = UIActivityViewController(activityItems: [context.coordinator], applicationActivities: applicationActivities)
Also, I wanted to be able to set the icon, title and subtitle in the share sheet, so I have implemented func activityViewControllerLinkMetadata in the Coordinator class.
The following is the complete expanded version of Mike W.'s answer. Please note you will need to add import LinkPresentation to the code.
ActivityViewController
import SwiftUI
import LinkPresentation
struct ActivityViewController: UIViewControllerRepresentable {
var shareable : ActivityShareable?
var applicationActivities: [UIActivity]? = nil
func makeUIViewController(context: UIViewControllerRepresentableContext<ActivityViewController>) -> UIActivityViewController {
let controller = UIActivityViewController(activityItems: [context.coordinator], applicationActivities: applicationActivities)
controller.modalPresentationStyle = .automatic
return controller
}
func updateUIViewController(_ uiViewController: UIActivityViewController, context: UIViewControllerRepresentableContext<ActivityViewController>) {}
func makeCoordinator() -> ActivityViewController.Coordinator {
Coordinator(self.shareable)
}
class Coordinator : NSObject, UIActivityItemSource {
private let shareable : ActivityShareable?
init(_ shareable: ActivityShareable?) {
self.shareable = shareable
super.init()
}
func activityViewControllerPlaceholderItem(_ activityViewController: UIActivityViewController) -> Any {
guard let share = self.shareable else { return "" }
return share.getPlaceholderItem()
}
func activityViewController(_ activityViewController: UIActivityViewController, itemForActivityType activityType: UIActivity.ActivityType?) -> Any? {
guard let share = self.shareable else { return "" }
return share.itemForActivityType(activityType: activityType)
}
func activityViewController(_ activityViewController: UIActivityViewController, subjectForActivityType activityType: UIActivity.ActivityType?) -> String {
guard let share = self.shareable else { return "" }
return share.subjectForActivityType(activityType: activityType)
}
func activityViewControllerLinkMetadata(_ activityViewController: UIActivityViewController) -> LPLinkMetadata? {
guard let share = self.shareable else { return nil }
let metadata = LPLinkMetadata()
// share sheet preview title
metadata.title = share.shareSheetTitle()
// share sheet preview subtitle
metadata.originalURL = URL(fileURLWithPath: share.shareSheetSubTitle())
// share sheet preview icon
if let image = share.shareSheetIcon() {
let imageProvider = NSItemProvider(object: image)
metadata.imageProvider = imageProvider
metadata.iconrovider = imageProvider
}
return metadata
}
}
}
Protocol ActivityShareable
protocol ActivityShareable {
func getPlaceholderItem() -> Any
func itemForActivityType(activityType: UIActivity.ActivityType?) -> Any?
func subjectForActivityType(activityType: UIActivity.ActivityType?) -> String
func shareSheetTitle() -> String
func shareSheetSubTitle() -> String
func shareSheetIcon() -> UIImage?
}
In my case I am using the share sheet to export text, so I created a struct called ActivityShareableText that conforms to ActivityShareable:
struct ActivityShareableText: ActivityShareable {
let text: String
let title: String
let subTitle: String
let icon: UIImage?
func getPlaceholderItem() -> Any {
return text
}
func itemForActivityType(activityType: UIActivity.ActivityType?) -> Any? {
return text
}
func subjectForActivityType(activityType: UIActivity.ActivityType?) -> String {
return "\(title): \(subTitle)"
}
func shareSheetTitle() -> String {
return title
}
func shareSheetSubTitle() -> String {
return subTitle
}
func shareSheetIcon() -> UIImage? {
return icon
}
}
In my code, I call the share sheet as follows:
ActivityViewController(shareable: ActivityShareableText(
text: myShareText(),
title: myShareTitle(),
subTitle: myShareSubTitle(),
icon: UIImage(named: "myAppLogo")
))

FWIW - Providing a slight improvement to answers that includes an implementation for UIActivityItemSource. Code simplified for brevity, specifically around the default return on itemForActivityType and activityViewControllerPlaceholderItem, they must always return the same type.
ActivityViewController
struct ActivityViewController: UIViewControllerRepresentable {
var activityItems: [Any]
var shareable : ActivityShareable?
var applicationActivities: [UIActivity]? = nil
func makeUIViewController(context: UIViewControllerRepresentableContext<ActivityViewController>) -> UIActivityViewController {
let controller = UIActivityViewController(activityItems: activityItems, applicationActivities: applicationActivities)
controller.modalPresentationStyle = .automatic
return controller
}
func updateUIViewController(_ uiViewController: UIActivityViewController, context: UIViewControllerRepresentableContext<ActivityViewController>) {}
func makeCoordinator() -> ActivityViewController.Coordinator {
Coordinator(self.shareable)
}
class Coordinator : NSObject, UIActivityItemSource {
private let shareable : ActivityShareable?
init(_ shareable: ActivityShareable?) {
self.shareable = shareable
super.init()
}
func activityViewControllerPlaceholderItem(_ activityViewController: UIActivityViewController) -> Any {
guard let share = self.shareable else { return "" }
return share.getPlaceholderItem()
}
func activityViewController(_ activityViewController: UIActivityViewController, itemForActivityType activityType: UIActivity.ActivityType?) -> Any? {
guard let share = self.shareable else { return "" }
return share.itemForActivityType(activityType: activityType)
}
func activityViewController(_ activityViewController: UIActivityViewController, subjectForActivityType activityType: UIActivity.ActivityType?) -> String {
guard let share = self.shareable else { return "" }
return share.subjectForActivityType(activityType: activityType)
}
}
}
ActivityShareable
protocol ActivityShareable {
func getPlaceholderItem() -> Any
func itemForActivityType(activityType: UIActivity.ActivityType?) -> Any?
/// Optional
func subjectForActivityType(activityType: UIActivity.ActivityType?) -> String
}
extension ActivityShareable {
func subjectForActivityType(activityType: UIActivity.ActivityType?) -> String {
return ""
}
}
You could pass in the reference for ActivityViewController or the underlying UIActivityViewController but that feels unnecessary.

You could try porting UIActivityViewController to SwiftUI as follows:
struct ActivityView: UIViewControllerRepresentable {
let activityItems: [Any]
let applicationActivities: [UIActivity]?
func makeUIViewController(context: UIViewControllerRepresentableContext<ActivityView>) -> UIActivityViewController {
return UIActivityViewController(activityItems: activityItems,
applicationActivities: applicationActivities)
}
func updateUIViewController(_ uiViewController: UIActivityViewController,
context: UIViewControllerRepresentableContext<ActivityView>) {
}
}
but the app will crash when you try to display it.
I tried: Modal, Popover and NavigationButton.
To test it:
struct ContentView: View {
var body: some Body {
EmptyView
.presentation(Modal(ActivityView()))
}
}
It doesn't seem to be usable from SwiftUI.

Extending upon #Shimanski Artem solution. I think we can write that code more concise. So I basically embed my ActivityViewController in a blank UIViewController and present it from there. This way we don't get the full 'overlay' sheet and you get the native behaviour. Just like #Shimanski Artem did.
struct UIKitActivityView: UIViewControllerRepresentable {
#Binding var isPresented: Bool
let data: [Any]
func makeUIViewController(context: Context) -> UIViewController {
UIViewController()
}
func updateUIViewController(_ uiViewController: UIViewController, context: Context) {
let activityViewController = UIActivityViewController(
activityItems: data,
applicationActivities: nil
)
if isPresented && uiViewController.presentedViewController == nil {
uiViewController.present(activityViewController, animated: true)
}
activityViewController.completionWithItemsHandler = { (_, _, _, _) in
isPresented = false
}
}
}
Usage
struct ActivityViewTest: View {
#State private var isActivityPresented = false
var body: some View {
Button("Preset") {
self.isActivityPresented = true
}
.background(
UIKitActivityView(
isPresented: $viewModel.showShareSheet,
data: ["String"]
)
)
}
}

Example using SwiftUIX
There is a library called SwiftUIX that already has a wrapper for UIActivityViewController. See quick skeleton of how to present it via .sheet() which should be placed somewhere in the var body: some View {}.
import SwiftUIX
/// ...
#State private var showSocialsInviteShareSheet: Bool = false
// ...
.sheet(isPresented: $showSocialsInviteShareSheet, onDismiss: {
print("Dismiss")
}, content: {
AppActivityView(activityItems: [URL(string: "https://www.apple.com")!])
})

Suggest another way to solve it 🤔
You can create the Empty View Controller to present the sheet
struct ShareSheet: UIViewControllerRepresentable {
// To setup the share sheet
struct Config {
let activityItems: [Any]
var applicationActivities: [UIActivity]?
var excludedActivityTypes: [UIActivity.ActivityType]?
}
// Result object
struct Result {
let error: Error?
let activityType: UIActivity.ActivityType?
let completed: Bool
let returnedItems: [Any]?
}
#Binding var isPresented: Bool
private var handler: ((Result) -> Void)?
private let shareSheet: UIActivityViewController
init(
isPresented: Binding<Bool>,
config: Config,
onEnd: ((Result) -> Void)? = nil
) {
self._isPresented = isPresented
shareSheet = UIActivityViewController(
activityItems: config.activityItems,
applicationActivities: config.applicationActivities
)
shareSheet.excludedActivityTypes = config.excludedActivityTypes
shareSheet.completionWithItemsHandler = { activityType, completed, returnedItems, error in
onEnd?(
.init(
error: error,
activityType: activityType,
completed: completed,
returnedItems: returnedItems
)
)
// Set isPresented to false after complete
isPresented.wrappedValue = false
}
}
func makeUIViewController(context: Context) -> UIViewController {
UIViewController()
}
func updateUIViewController(
_ uiViewController: UIViewController,
context: Context
) {
if isPresented, shareSheet.view.window == nil {
uiViewController.present(shareSheet, animated: true, completion: nil)
} else if !isPresented, shareSheet.view.window != nil {
shareSheet.dismiss(animated: true)
}
}
}
You can also create the operator in the view extension
extension View {
func shareSheet(
isPresented: Binding<Bool>,
config: ShareSheet.Config,
onEnd: ((ShareSheet.Result) -> Void)? = nil
) -> some View {
self.background(
ShareSheet(isPresented: isPresented, config: config, onEnd: onEnd)
)
}
}

Thanks for the helpful answers in this thread.
I tried to solve the stale data problem. The issue from not not implementing updateUIViewController in UIViewControllerRepresentable. SwiftUI calls makeUIViewController only once to create the view controller. The method updateUIViewController is responsible to make changes to view controller based on changes of the SwiftUI view.
As UIActivityViewController does not allow to change activityItems and applicationActivities, I used a wrapper view controller. UIViewControllerRepresentable will update the wrapper and the wrapper will create a new UIActivityViewController as needed to perform the update.
Below my code to implement a "share" button in my application. The code is tested on iOS 13.4 beta, which has fixed several SwiftUI bugs - not sure if it works on earlier releases.
struct Share: View {
var document: ReaderDocument // UIDocument subclass
#State var showShareSheet = false
var body: some View {
Button(action: {
self.document.save(to: self.document.fileURL, for: .forOverwriting) { success in
self.showShareSheet = true
}
}) {
Image(systemName: "square.and.arrow.up")
}.popover(isPresented: $showShareSheet) {
ActivityViewController(activityItems: [ self.document.text, self.document.fileURL,
UIPrintInfo.printInfo(), self.printFormatter ])
.frame(minWidth: 320, minHeight: 500) // necessary for iPad
}
}
var printFormatter: UIPrintFormatter {
let fontNum = Preferences.shared.readerFontSize.value
let fontSize = ReaderController.readerFontSizes[fontNum < ReaderController.readerFontSizes.count ? fontNum : 1]
let printFormatter = UISimpleTextPrintFormatter(text: self.document.text)
printFormatter.startPage = 0
printFormatter.perPageContentInsets = UIEdgeInsets(top: 72, left: 72, bottom: 72, right: 72)
return printFormatter
}
}
struct ActivityViewController: UIViewControllerRepresentable {
var activityItems: [Any]
var applicationActivities: [UIActivity]? = nil
#Environment(\.presentationMode) var presentationMode
func makeUIViewController(context: UIViewControllerRepresentableContext<ActivityViewController>)
-> WrappedViewController<UIActivityViewController> {
let controller = WrappedViewController(wrappedController: activityController)
return controller
}
func updateUIViewController(_ uiViewController: WrappedViewController<UIActivityViewController>,
context: UIViewControllerRepresentableContext<ActivityViewController>) {
uiViewController.wrappedController = activityController
}
private var activityController: UIActivityViewController {
let avc = UIActivityViewController(activityItems: activityItems, applicationActivities: applicationActivities)
avc.completionWithItemsHandler = { (_, _, _, _) in
self.presentationMode.wrappedValue.dismiss()
}
return avc
}
}
class WrappedViewController<Controller: UIViewController>: UIViewController {
var wrappedController: Controller {
didSet {
if (wrappedController != oldValue) {
oldValue.removeFromParent()
oldValue.view.removeFromSuperview()
addChild(wrappedController)
view.addSubview(wrappedController.view)
wrappedController.view.frame = view.bounds
}
}
}
init(wrappedController: Controller) {
self.wrappedController = wrappedController
super.init(nibName: nil, bundle: nil)
addChild(wrappedController)
}
required init?(coder: NSCoder) {
fatalError("init(coder:) has not been implemented")
}
override func loadView() {
super.loadView()
view.addSubview(wrappedController.view)
wrappedController.view.frame = view.bounds
}
}

Just use introspect. Then you can easily code something like this:
YourView().introspectViewController { controller in
guard let items = viewModel.inviteLinkParams, viewModel.isSharePresented else { return }
let activity = UIActivityViewController(activityItems: items, applicationActivities: nil)
controller.present(activity, animated: true, completion: nil)
}

Swift 5 / SwiftUI Native
Simple, with completion call-back and native SwiftUI #Binding
import SwiftUI
struct ShareSheet: UIViewControllerRepresentable {
typealias Callback = (_ activityType: UIActivity.ActivityType?, _ completed: Bool, _ returnedItems: [Any]?, _ error: Error?) -> Void
#Binding var isPresented: Bool
#Binding var activityItem: String
let applicationActivities: [UIActivity]? = nil
let excludedActivityTypes: [UIActivity.ActivityType]? = nil
let callback: Callback?
func makeUIViewController(context: Context) -> UIActivityViewController {
let controller = UIActivityViewController(
activityItems: [activityItem],
applicationActivities: applicationActivities)
controller.excludedActivityTypes = excludedActivityTypes
controller.completionWithItemsHandler = { (activityType, completed, returnedItems, error) in
callback?(activityType, completed, returnedItems, error)
isPresented = false
}
return controller
}
func updateUIViewController(_ uiViewController: UIActivityViewController, context: Context) {
}
}
example usage:
ShareSheet(isPresented: $showShareSheet, activityItem: $sharingUrl, callback: { activityType, completed, returnedItems, error in
print("ShareSheet dismissed: \(activityType) \(completed) \(returnedItems) \(error)")
})

Related

NSContactPicker not displaying picker window in SwiftUI on macOS

I have tried to get the NSContactPicker to display a picker window in SwiftUI on macOS. Here is my code. If you click on the button nothing happens. What am I missing?
import SwiftUI
import Contacts
import ContactsUI
let d = MyContactPicker()
class MyContactPicker: NSObject, CNContactPickerDelegate
{
var contactName: String = "No user selected"
func pickContact()
{
let contactPicker = CNContactPicker()
contactPicker.delegate = self
}
func contactPicker(_ picker: CNContactPicker, didSelect contact: CNContact)
{
contactName = contact.givenName
}
}
struct ContentView: View
{
#State var contact: CNContact?
var picker = MyContactPicker()
var body: some View
{
VStack
{
Text(picker.contactName)
Button("Select Contact")
{
picker.pickContact()
}
}
}
}
Here's a possible starting point using NSViewRepresentable and an NSView subclass
class NSContactPickerView: NSView, CNContactPickerDelegate {
let didSelectContact: (CNContact) -> Void
init(didSelectContact: #escaping (CNContact) -> Void) {
self.didSelectContact = didSelectContact
super.init(frame: .zero)
Task {
showPicker()
}
}
required init?(coder: NSCoder) {
fatalError("init(coder:) has not been implemented")
}
func showPicker() {
let picker = CNContactPicker()
picker.delegate = self
picker.showRelative(to: .zero, of: self, preferredEdge: .maxY)
}
func contactPicker(_ picker: CNContactPicker, didSelect contact: CNContact) {
didSelectContact(contact)
}
}
struct ContactPicker: NSViewRepresentable {
let didSelectContact: (CNContact) -> Void
func makeNSView(context: Context) -> NSContactPickerView {
NSContactPickerView(didSelectContact: didSelectContact)
}
func updateNSView(_ nsView: NSContactPickerView, context: Context) {
}
}
struct ContentView: View {
#State var contact: CNContact?
#State private var showPicker = false
var body: some View {
VStack {
Text(contact?.givenName ?? "")
Button("Select Contact") {
showPicker = true
}
}
.sheet(isPresented: $showPicker) {
ContactPicker { contact in
self.contact = contact
}
.frame(width: 1, height: 1)
}
}
}
It works, but it's not very elegant. Maybe someone else can improve on this.

Start / update View in userContentController - Function

I try to start a second view with the help of the WKWebview by clicking a button.
It also works. I get a callback in the function userContentController. How is it possible to start a new view in the app from this function.
struct MyWebView: UIViewRepresentable {
var webPageURL = "https://google.de"
func updateUIView(_ uiView: WKWebView, context: Context) {
let myURL = URL(string:webPageURL)
let myRequest = URLRequest(url: myURL!)
uiView.load(myRequest)
}
func makeUIView(context: Context) -> WKWebView {
let webConfiguration = WKWebViewConfiguration()
let wkcontentController = WKUserContentController()
wkcontentController.add(context.coordinator, name: "doStuffMessageHandler")
webConfiguration.userContentController = wkcontentController
let webView = WKWebView(frame: .zero,configuration: webConfiguration)
context.coordinator.parent = webView // inject as weak
return webView
}
func makeCoordinator() -> ContentController {
ContentController() // let handler be a coordinator
}
}
class ContentController: NSObject, WKScriptMessageHandler {
weak var parent: WKWebView? // weak to avoid reference cycling
func userContentController(_ userContentController: WKUserContentController, didReceive message: WKScriptMessage)
{
if message.name == "doStuffMessageHandler"
{
print(message.body)
}
}
}
struct MyWebView_Previews: PreviewProvider {
static var previews: some View {
MyWebView()
}
}
The possible solution is using notifications (which allows keep those components independent).
extension Notification.Name {
static let didReceiveMessage = Notification.Name("didReceiveMessage")
}
class ContentController: NSObject, WKScriptMessageHandler {
weak var parent: WKWebView? // weak to avoid reference cycling
func userContentController(_ userContentController: WKUserContentController, didReceive message: WKScriptMessage)
{
if message.name == "doStuffMessageHandler"
{
NotificationCenter.default.post(name: .didReceiveMessage, object: message.body)
}
}
}
struct DemoHandleMessage: View {
#State private var showMessage = false
#State private var message: String? = nil
var body: some View {
VStack {
if showMessage {
// switch back via bound flag to showMessage state
MessageView(text: message, dismiss: $showMessage)
} else {
MyWebView()
}
}.onReceive(NotificationCenter.default.publisher(for: .didReceiveMessage)) { notification in
self.message = notification.object as? String
self.showMessage = true
}
}
}

Why does my TabView change back to Home tab when image loads?

I created a TabView with two tabs. One is Home and the other loads text and an image from NASA pic of the day API. When I change to the NASA pic of the day, I see "Loading data" until the data loads. Once the data is loaded, for some reason the tab switches back to the "Home" tab. After this bug happens, I can switch back and forth between the two tabs normally and everything is loaded. Why does the tab get switched back to the home tab? Thank you!!
APIImageView Code:
import SwiftUI
struct ApiImageView: View {
#ObservedObject var apiImage = ApiImage()
var body: some View {
Group {
if apiImage.dataHasLoaded {
VStack {
Text(apiImage.title!)
.font(.largeTitle)
Image(uiImage: apiImage.image!).resizable()
.cornerRadius(10)
.padding()
ScrollView(.vertical, showsIndicators: false) {
Text(apiImage.explanation!)
.font(.subheadline)
.padding()
}
}
} else {
Text("Loading Data")
}
}.onAppear {
self.apiImage.loadImageFromApi(urlString: "https://api.nasa.gov/planetary/apod?api_key=eaRYg7fgTemadUv1bQawGRqCWBgktMjolYwiRrHK")
}
}
}
struct ApiImageView_Previews: PreviewProvider {
static var previews: some View {
ApiImageView()
}
}
APIImage Code:
import SwiftUI
class ApiImage: ObservableObject {
#Published var dataHasLoaded = false
#Published var image: UIImage? = nil
#Published var title: String? = nil
#Published var explanation: String? = nil
}
extension ApiImage {
func loadImageFromApi(urlString: String) {
let url = URL(string: urlString)!
var request = URLRequest(url: url)
request.httpMethod = "GET"
let task = URLSession.shared.dataTask(with: request, completionHandler: parseJsonObject)
task.resume()
}
func parseJsonObject(data: Data?, urlResponse: URLResponse?, error: Error?) {
guard error == nil else {
print("\(error!)")
return
}
guard let content = data else {
print("No data")
return
}
let json = try! JSONSerialization.jsonObject(with: content)
let jsonmap = json as! [String : Any]
let titleText = jsonmap["title"] as! String
let explanationText = jsonmap["explanation"] as! String
let urlString = jsonmap["url"] as! String
print("\(urlString)")
print("\(titleText)")
print("\(explanationText)")
DispatchQueue.main.async {
self.title = titleText
self.explanation = explanationText
}
let url = URL(string: urlString)!
var request = URLRequest(url: url)
request.httpMethod = "GET"
let task = URLSession.shared.dataTask(with: request, completionHandler: setImageFromData)
task.resume()
}
func setImageFromData(data: Data?, urlResponse: URLResponse?, error: Error?) {
guard error == nil else {
print("\(error!)")
return
}
guard let content = data else {
print("No data")
return
}
DispatchQueue.main.async {
self.image = UIImage(data: content)
self.dataHasLoaded = true
}
}
}
MainTabView Code:
import SwiftUI
struct MainTabView: View {
var body: some View {
TabView {
CategoryHome()
.tabItem {
Image(systemName: "house.fill")
Text("Landmarks")
.tag(0)
}
ApiImageView()
.tabItem {
Image(systemName: "flame.fill")
Text("NASA Pic")
//.tag(1)
}
}
}
}
struct MainTabView_Previews: PreviewProvider {
static var previews: some View {
MainTabView()
}
}
Maybe not directly a solution, but also important: it seems that the MainTabView is not entirely correct (the .tag() should be outside the .tabItem closure). This would be a correct version:
import SwiftUI
struct MainTabView: View {
var body: some View {
TabView {
CategoryHome()
.tabItem {
Image(systemName: "house.fill")
Text("Landmarks")
}.tag(0)
ApiImageView()
.tabItem {
Image(systemName: "flame.fill")
Text("NASA Pic")
}.tag(1)
}
}
}
struct MainTabView_Previews: PreviewProvider {
static var previews: some View {
MainTabView()
}
}
Maybe this is already the solution; if not, I hope it is still helpful! :)

Change State with DocumentPicker SwiftUI

I'm trying to get a List View to appear after selecting a document with documentPicker. Getting the following error...
Fatal error: No ObservableObject of type Switcher found.
A View.environmentObject(_:) for Switcher may be missing as an ancestor of this view.: file /BuildRoot/Library/Caches/com.apple.xbs/Sources/Monoceros/Monoceros-30.4/Core/EnvironmentObject.swift, line 55
It seems like I should use an EnviromentObject binding to have all views be able to read, access and update the Switcher class. Under the Coordinator Class in CSVDocumentPicker.swift is where things seem to go wrong.
I'm using #EnvironmentObject var switcher:Switcher and using the documentPicker function to toggle the switcher state so the Lists View will be displayed. I'm stumped.
SceneDelegate.swift
import UIKit
import SwiftUI
class SceneDelegate: UIResponder, UIWindowSceneDelegate {
var window: UIWindow?
var switcher = Switcher()
func scene(_ scene: UIScene, willConnectTo session: UISceneSession, options connectionOptions: UIScene.ConnectionOptions) {
let contentView = ContentView().environmentObject(Switcher())
if let windowScene = scene as? UIWindowScene {
let window = UIWindow(windowScene: windowScene)
window.rootViewController = UIHostingController(rootView: contentView.environmentObject(switcher))
self.window = window
window.makeKeyAndVisible()
}
}
func sceneDidDisconnect(_ scene: UIScene) {
}
func sceneDidBecomeActive(_ scene: UIScene) {
}
func sceneWillResignActive(_ scene: UIScene) {
}
func sceneWillEnterForeground(_ scene: UIScene) {
}
func sceneDidEnterBackground(_ scene: UIScene) {
}
}
CSVDocumentPicker.swift
import Combine
import SwiftUI
class Switcher: ObservableObject {
var didChange = PassthroughSubject<Bool, Never>()
var isEnabled = false {
didSet {
didChange.send(self.isEnabled)
}
}
}
struct CSVDocumentPicker: View {
#EnvironmentObject var switcher:Switcher
#State private var isPresented = false
var body: some View {
VStack{
Text("csvSearch")
Button(action: {self.isPresented = true
})
{Text("import")
Image(systemName: "folder").scaledToFit()
}.sheet(isPresented: $isPresented) {
() -> DocumentPickerViewController in
DocumentPickerViewController.init(onDismiss: {
self.isPresented = false
})
}
if switcher.isEnabled {
ListView()
}
}
}
}
struct CSVDocumentPicker_Previews: PreviewProvider {
static var previews: some View {
CSVDocumentPicker().environmentObject(Switcher())
}
}
/// Wrapper around the `UIDocumentPickerViewController`.
struct DocumentPickerViewController {
private let supportedTypes: [String] = ["public.item"]
// Callback to be executed when users close the document picker.
private let onDismiss: () -> Void
init(onDismiss: #escaping () -> Void) {
self.onDismiss = onDismiss
}
}
// MARK: - UIViewControllerRepresentable
extension DocumentPickerViewController: UIViewControllerRepresentable {
typealias UIViewControllerType = UIDocumentPickerViewController
func makeUIViewController(context: Context) -> DocumentPickerViewController.UIViewControllerType {
let documentPickerController = UIDocumentPickerViewController(documentTypes: supportedTypes, in: .import)
documentPickerController.allowsMultipleSelection = false
documentPickerController.delegate = context.coordinator
return documentPickerController
}
func updateUIViewController(_ uiViewController: DocumentPickerViewController.UIViewControllerType, context: Context) {}
// MARK: Coordinator
func makeCoordinator() -> Coordinator {
Coordinator(self)
}
class Coordinator: NSObject, UIDocumentPickerDelegate, ObservableObject {
#EnvironmentObject var switcher:Switcher
var parent: DocumentPickerViewController
init(_ documentPickerController: DocumentPickerViewController) {
parent = documentPickerController
}
func documentPicker(_ controller: UIDocumentPickerViewController, didPickDocumentAt url: URL) {
globalPathToCsv = url
loadCSV()
switcher.isEnabled.toggle()
}
func documentPickerWasCancelled(_ controller: UIDocumentPickerViewController) {
parent.onDismiss()
}
}
}
ContentView.swift
import SwiftUI
import UIKit
var globalPathToCsv:URL!
var csvArray = [[String:String]]()
var csv = CSVaccessability()
func loadCSV(){
csv.csvToList()
// print(csvArray)
}
struct ContentView: View {
#EnvironmentObject var switcher:Switcher
var body: some View {
VStack{
CSVDocumentPicker().environmentObject(Switcher())
}
}
}
struct ContentView_Previews: PreviewProvider {
static var previews: some View {
ContentView().environmentObject(Switcher())
}
}
ListView.swift
import SwiftUI
struct ListView: View {
var body: some View {
HStack{
List {
ForEach(csvArray, id:\.self) { dict in Section {DataList(dict: dict)} }
}
}}
}
struct DataList : View {
#State var dict = [String: String]()
var body: some View {
let keys = dict.map{$0.key}
let values = dict.map {$0.value}
return ForEach(keys.indices) {index in
HStack {
Text(keys[index])
Text("\(values[index])")
}
}
}
}
struct ListView_Previews: PreviewProvider {
static var previews: some View {
ListView()
}
}
CSVaccessability.swift
import Foundation
import SwiftCSV
var csvData:[[String]]!
var headers:[String] = []
class CSVaccessability {
var numberOfColumns:Int!
var masterList = [[String:Any]]()
func csvToList(){
if let url = globalPathToCsv {
do {
print(url)
let csvFile: CSV = try CSV(url: globalPathToCsv)
let csv = csvFile
//print(stream)
//print(csvFile)
headers = csv.header
csvArray=csv.namedRows
} catch {print("contents could not be loaded")}}
else {print("the URL was bad!")}
}
}
I've imported SwiftCSV for this project...
Created a new class...
ToggleView.swift
import Foundation
class ToggleView: ObservableObject {
#Published var toggleView: Bool = false
}
Added the Environment Object to ContentView.swift
#EnvironmentObject var viewToggle: ToggleView
Also added .environmentObject(ToggleView()) to any view that would be called and cause a crash the crash logs helped with this...
Text("csvSearch")
Button(action: {self.isPresented = true
self.viewToggle.toggleView.toggle()
// self.switcher = true
})
{Text("import")
Image(systemName: "folder").scaledToFit()
}.sheet(isPresented: $isPresented) {
() -> DocumentPickerViewController in
DocumentPickerViewController.init()
}
if self.picker {
DocumentPickerViewController().environmentObject(ToggleView())
}
if self.viewToggle.toggleView{
ListView()
}
}
}
}
Did you ever get this working? The only problem I found was with the line var csv = CSVaccessability() in the ContentView. CSVaccessability does not exist.
This is my solution for the Catalyst app for Mac, but to avoid pressing theImage (systemName: "book")button a second time to update the data in the text fields, I have implemented a hidden view in GeoFolderReadFileView to force the view update.
//File: GeoFolderCodStruct
import Foundation
struct GeoFolderCodStruct:Codable {
var isActive:Bool = true
var dataCreazione:Date = Date()
var geoFolderPath:String = ""
var nomeCartella:String = ""
var nomeCommittente:String = ""
var nomeArchivio:String = ""
var note:String = ""
var latitudine:Double? = nil
var longitudine:Double? = nil
var radiusCircle:Int16? = nil
//Roma 42.1234 13.1234
}
//File: PickerForReadFile
import SwiftUI
final class PickerForReadFile: NSObject, UIViewControllerRepresentable, ObservableObject {
#Published var geoFolder = GeoFolderCodStruct()
lazy var viewController:UIDocumentPickerViewController = {
let vc = UIDocumentPickerViewController(documentTypes: ["geof"], in: .open)
vc.allowsMultipleSelection = false
vc.delegate = self
return vc
}()
func makeUIViewController(context: UIViewControllerRepresentableContext<PickerForReadFile>) -> UIDocumentPickerViewController {
viewController.delegate = self
return viewController
}
func updateUIViewController(_ uiViewController: UIDocumentPickerViewController, context: UIViewControllerRepresentableContext<PickerForReadFile>) {
print("updateUIViewController")
}
}
extension PickerForReadFile: UIDocumentPickerDelegate {
func documentPicker(_ controller: UIDocumentPickerViewController, didPickDocumentsAt urls: [URL]) {
if urls.count > 0 {
DispatchQueue.main.async {
let url = urls[0]
do {
let data = try Data(contentsOf: url)
let decoder = JSONDecoder()
decoder.dateDecodingStrategy = .formatted(dateFormatter)
let jsonData = try decoder.decode(GeoFolderCodStruct.self, from: data)
self.geoFolder = jsonData
print("geoFolder: \(self.geoFolder.nomeArchivio)")
} catch {
print("error:\(error)")
}
}
}
}
func documentPickerWasCancelled(_ controller: UIDocumentPickerViewController) {
controller.dismiss(animated: true) {
print("Cancel from picker view controller")
}
}
}
//File: GeoFolderReadFileView
import SwiftUI
struct GeoFolderReadFileView: View {
#ObservedObject var picker = PickerForReadFile()
#Binding var geoFolder: GeoFolderCodStruct
var body: some View {
VStack(alignment: .trailing){
Button(action: {
#if targetEnvironment(macCatalyst)
print("Press open file")
let vc = UIApplication.shared.windows[0].rootViewController!
vc.present(self.picker.viewController, animated: true) {
self.geoFolder = self.picker.geoFolder
}
#endif
}) {
Image(systemName: "book")
}
urlPickedView()
.hidden()
}
}
private func urlPickedView() -> some View {
DispatchQueue.main.async {
let geoF = self.picker.geoFolder
print("Committente: \(geoF.nomeCommittente) - Archivio: \(geoF.nomeArchivio)")
self.geoFolder = geoF
}
return TextField("", text: $geoFolder.geoFolderPath)
}
}
//File: ContentView
import SwiftUI
struct ContentView: View {
#State private var geoFolder = GeoFolderCodStruct()
var body: some View {
VStack {
HStack {
Text("Open GeoFolder File:")
.padding()
Spacer()
GeoFolderReadFileView(geoFolder: $geoFolder)
.padding()
}
.padding()
Group {
TextField("", text: $geoFolder.geoFolderPath)
.textFieldStyle(RoundedBorderTextFieldStyle())
.padding()
TextField("", text: $geoFolder.nomeCartella)
.textFieldStyle(RoundedBorderTextFieldStyle())
.padding()
TextField("", text: $geoFolder.nomeCommittente)
.textFieldStyle(RoundedBorderTextFieldStyle())
.padding()
TextField("", text: $geoFolder.nomeArchivio)
.textFieldStyle(RoundedBorderTextFieldStyle())
.padding()
TextField("", text: $geoFolder.note)
.textFieldStyle(RoundedBorderTextFieldStyle())
.padding()
}
.padding()
}
}
}
struct ContentView_Previews: PreviewProvider {
static var previews: some View {
ContentView()
}
}
and the last, the json file to read for test the code.
{
"nomeCommittente" : "Appple",
"note" : "Image from Cupertino (CA).",
"latitudine" : 37.332161,
"longitudine" : -122.030352,
"nomeCartella" : "Foto",
"geoFolderPath" : "\/Users\/cesare\/Desktop",
"radiusCircle" : 50,
"dataCreazione" : "20\/03\/2020",
"nomeArchivio" : "AppleCampus-Image",
"isActive" : true
}
I was unable to implement the solution proposed by #Mdoyle1. I hope someone can edit the code to make it work as it should, without create hidden view.

UIView[Controller]Representable: SwiftUI Subview is shown in Debugger, but not when run

Because the ScrollView does not provide a function to set the contentOffset, I'm trying to use the UIScrollView as UIViewRepresentable. The attached code shows both, the caller and the definition of the view and the view controller.
When running the code in simulator or previews, just a blue area is shown. When debugging the display, the Text is shown, as expected.
If have no idea about the reason - is it because I'm doing something wrong, or because there's a bug in Xcode or SwiftUI?
Here the custom scroll view:
struct PositionableScrollView<Content>: UIViewRepresentable where Content: View {
var content: () -> Content
init(#ViewBuilder content: #escaping () -> Content) {
self.content = content
}
func makeUIView(context: UIViewRepresentableContext<PositionableScrollView<Content>>) -> UIScrollView {
let scrollViewVC = PositionableScrollViewVC<Content>(nibName: nil, bundle: nil)
scrollViewVC.add(content: content)
let control = scrollViewVC.scrollView
return control
}
func updateUIView(_ uiView: UIScrollView, context: UIViewRepresentableContext<PositionableScrollView<Content>>) {
// Do nothing at the moment.
}
}
The view controller:
final class PositionableScrollViewVC<Content>: UIViewController where Content: View {
var scrollView: UIScrollView = UIScrollView()
var contentView: UIView!
var contentVC: UIViewController!
override init(nibName nibNameOrNil: String?, bundle nibBundleOrNil: Bundle?) {
super.init(nibName: nibNameOrNil, bundle: nibBundleOrNil)
setup()
}
required init?(coder: NSCoder) {
super.init(coder: coder)
setup()
}
func setup() {
self.view.addSubview(self.scrollView)
self.scrollView.leadingAnchor.constraint(equalTo: view.leadingAnchor).isActive = true
self.scrollView.trailingAnchor.constraint(equalTo: view.trailingAnchor).isActive = true
self.scrollView.topAnchor.constraint(equalTo: view.topAnchor).isActive = true
self.scrollView.bottomAnchor.constraint(equalTo: view.bottomAnchor).isActive = true
self.scrollView.translatesAutoresizingMaskIntoConstraints = false
}
override func viewDidLoad() {
super.viewDidLoad()
debugPrint("self:", self.frame())
debugPrint("self.view:", self.view!.frame)
debugPrint("self.view.subviews:", self.view.subviews)
// debugPrint("self.view.subviews[0]:", self.view.subviews[0])
// debugPrint("self.view.subviews[0].subviews:", self.view.subviews[0].subviews)
}
func add(#ViewBuilder content: #escaping () -> Content) {
self.contentVC = UIHostingController(rootView: content())
self.contentView = self.contentVC.view!
self.scrollView.addSubview(contentView)
self.contentView.leadingAnchor.constraint(equalTo: self.scrollView.leadingAnchor).isActive = true
self.contentView.trailingAnchor.constraint(equalTo: self.scrollView.trailingAnchor).isActive = true
self.contentView.topAnchor.constraint(equalTo: self.scrollView.topAnchor).isActive = true
self.contentView.bottomAnchor.constraint(equalTo: self.scrollView.bottomAnchor).isActive = true
self.contentView.translatesAutoresizingMaskIntoConstraints = false
self.contentView.widthAnchor.constraint(greaterThanOrEqualTo: self.scrollView.widthAnchor).isActive = true
}
}
extension PositionableScrollViewVC: UIViewControllerRepresentable {
func makeUIViewController(context: UIViewControllerRepresentableContext<PositionableScrollViewVC>) -> PositionableScrollViewVC {
let vc = PositionableScrollViewVC()
return vc
}
func updateUIViewController(_ uiViewController: PositionableScrollViewVC, context: UIViewControllerRepresentableContext<PositionableScrollViewVC>) {
// Do nothing at the moment.
}
}
The callers:
struct TimelineView: View {
#State private var posX: CGFloat = 0
var body: some View {
GeometryReader { geo in
VStack {
Text("\(self.posX) || \(geo.frame(in: .global).width)")
PositionableScrollView() {
VStack {
Spacer()
Text("Hallo")
.background(Color.yellow)
Spacer()
}
.frame(width: 1000, height: 200, alignment: .bottomLeading)
}
.background(Color.blue)
}
}
}
}
struct TimelineView_Previews: PreviewProvider {
static var previews: some View {
TimelineView()
}
}
The display, when run, and in debugger:

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