In UIKit I used below code to present a modal Viewcontroller with presentation style crossDissolve
controller.modalTransitionStyle = .crossDissolve
controller.modalPresentationStyle = .overFullScreen
UIApplication.topViewController()?.present(controller, animated: true, completion: nil)
But how I can achieve this in swiftUI?
You can make an extension on UIViewController like this:
struct ViewControllerHolder {
weak var value: UIViewController?
}
struct ViewControllerKey: EnvironmentKey {
static var defaultValue: ViewControllerHolder {
return ViewControllerHolder(value: UIApplication.shared.windows.first?.rootViewController)
}
}
extension EnvironmentValues {
var viewController: UIViewController? {
get { return self[ViewControllerKey.self].value }
set { self[ViewControllerKey.self].value = newValue }
}
}
extension UIViewController {
func present<Content: View>(style: UIModalPresentationStyle = .automatic, transitionStyle: UIModalTransitionStyle = .coverVertical, #ViewBuilder builder: () -> Content) {
let toPresent = UIHostingController(rootView: AnyView(EmptyView()))
toPresent.modalPresentationStyle = style
toPresent.modalTransitionStyle = transitionStyle
toPresent.rootView = AnyView(
builder()
.environment(\.viewController, toPresent)
)
self.present(toPresent, animated: true, completion: nil)
}
}
and use it as you want in your SwiftUI code:
struct ContentView: View {
#Environment(\.viewController) private var viewControllerHolder: UIViewController?
private var viewController: UIViewController? {
self.viewControllerHolder
}
var body: some View {
Button(action: {
self.viewController?.present(style: .fullScreen, transitionStyle: .coverVertical) {
Text("OK")
}
}) {
Text("Present me!")
}
}
}
In this way, you have an ability to change your presentation and transition style as you want
Related
I'm using a UITabController in my SwiftUI app and it works well, except for one issue.
When I have a NavigationView that uses a large title, it changes to inline as I scroll, as expected. So far so good.
When I switch tabs, then switch back again, it should remember the scroll position and therefore be inline. Instead, it very briefly flickers as a large title before moving to inline.
This only seems to happen on device.
Screen recording of the issue
Is anyone able to help me with a workaround?
struct ContentView: View {
var body: some View {
CustomTabView([
Tab(view: FirstView(),
barItem: UITabBarItem(title: "First", image: UIImage(systemName: "1.circle"), selectedImage: nil)),
Tab(view: SecondView(),
barItem: UITabBarItem(title: "Second", image: UIImage(systemName: "2.circle"), selectedImage: nil))
])
}
}
struct FirstView: View {
var body: some View {
NavigationView {
List {
ForEach( 0...40, id: \.self ) {
Text("\($0)")
.padding()
}
}
.navigationTitle("First View")
}
}
}
struct SecondView: View {
var body: some View {
NavigationView {
List {
ForEach( 41...80, id: \.self ) {
Text("\($0)")
.padding()
}
}
.navigationTitle("Second View")
}
}
}
struct TabBarController: UIViewControllerRepresentable {
var controllers: [UIViewController]
func makeUIViewController(context: Context) -> UITabBarController {
let tabBarController = UITabBarController()
tabBarController.viewControllers = controllers
tabBarController.delegate = context.coordinator
return tabBarController
}
func updateUIViewController(_ uiViewController: UITabBarController, context: Context) {}
func makeCoordinator() -> Coordinator {
Coordinator()
}
class Coordinator: NSObject, UITabBarControllerDelegate {
func tabBarController(_ tabBarController: UITabBarController, shouldSelect viewController: UIViewController) -> Bool {
guard let fromView = tabBarController.selectedViewController?.view, let toView = viewController.view else {
return false
}
if fromView != toView {
fromView.superview!.addSubview(toView)
}
return true
}
}
}
struct CustomTabView: View {
var viewControllers: [UIHostingController<AnyView>]
init(_ tabs: [Tab]) {
self.viewControllers = tabs.map {
let host = UIHostingController(rootView: $0.view)
host.tabBarItem = $0.barItem
return host
}
}
var body: some View {
TabBarController(controllers: viewControllers)
.edgesIgnoringSafeArea(.all)
}
}
struct Tab {
var view: AnyView
var barItem: UITabBarItem
init<V: View>(view: V, barItem: UITabBarItem) {
self.view = AnyView(view)
self.barItem = barItem
}
}
I have found a workaround / fix.
I needed to use a custom UIHostingController, find the navigation controller, and add a line to the viewWillAppear function:
public class MyHostingController: UIHostingController<AnyView> {
override open func viewWillAppear(_ animated: Bool) {
if let navigationController = navigationController() {
navigationController.view.setNeedsUpdateConstraints()
}
super.viewWillAppear(animated)
}
}
private extension UIViewController {
func navigationController() -> UINavigationController? {
var controller: UINavigationController?
if let navigationController = self as? UINavigationController {
return navigationController
}
children.forEach {
if let navigationController = $0 as? UINavigationController {
controller = navigationController
} else {
controller = $0.navigationController()
}
}
return controller
}
}
And then obvious replaced the two usages of UIHostingController in my original code with MyHostingController.
The most important line is this though:
navigationController.view.setNeedsUpdateConstraints()
Hope this helps anyone else that finds a similar issue.
It seems if you use UIViewControllerRepresentable to implement a view controller in your SwiftUI app, when you present it via sheet you cannot swipe to dismiss it. Is there something you need to do to support swipe to dismiss?
struct ContentView: View {
#State var showingPicker = false
var body: some View {
Text("Hello, world!")
.onAppear {
showingPicker = true
}
.sheet(isPresented: $showingPicker, content: {
PHPicker() //cannot swipe to dismiss
//Text("Test") //can swipe to dismiss
})
}
}
struct PHPicker: UIViewControllerRepresentable {
func makeUIViewController(context: UIViewControllerRepresentableContext<PHPicker>) -> PHPickerViewController {
let config = PHPickerConfiguration()
return PHPickerViewController(configuration: config)
}
func updateUIViewController(_ uiViewController: PHPickerViewController, context: UIViewControllerRepresentableContext<PHPicker>) { }
}
Possible solution is to add something like handle to drag (no styling - simplified for demo),
.sheet(isPresented: $showingPicker, content: {
VStack {
RoundedRectangle(cornerRadius: 8).fill(Color.gray)
.frame(width: 60, height: 8)
.padding(.top, 8)
PHPicker()
}
})
Alternate: the solution is to make presentation by UIKit completely and just pass activation binding inside representable.
Here is a demo of possible approach. Tested with Xcode 12.1 / iOS 14.1
struct PHPickerContentView: View {
#State var showingPicker = false
var body: some View {
Button("Picker") {
showingPicker = true
}
.background(PHPicker(isPresented: $showingPicker)) // << here !!
}
}
struct PHPicker: UIViewControllerRepresentable {
#Binding var isPresented: Bool
func makeUIViewController(context: Context) -> UIViewController {
UIViewController() // << picker presenter
}
func updateUIViewController(_ uiViewController: UIViewController, context: Context) {
// react on binding & show if not shown
if isPresented && uiViewController.presentedViewController == nil {
let config = PHPickerConfiguration()
let picker = PHPickerViewController(configuration: config)
picker.delegate = context.coordinator
uiViewController.present(picker, animated: true)
picker.presentationController?.delegate = context.coordinator
}
}
func makeCoordinator() -> Coordinator {
Coordinator(self)
}
class Coordinator: NSObject, PHPickerViewControllerDelegate, UIAdaptivePresentationControllerDelegate {
let owner: PHPicker
init(_ owner: PHPicker) {
self.owner = owner
}
func picker(_ picker: PHPickerViewController, didFinishPicking results: [PHPickerResult]) {
// picked image handling code here
picker.presentingViewController?.dismiss(animated: true)
owner.isPresented = false // << reset on action !!
}
func presentationControllerDidDismiss(_ presentationController: UIPresentationController) {
owner.isPresented = false // << reset on swipe !!
}
}
}
I know I can globally change the navigation bar using init:
init() {
UINavigationBar.appearance().largeTitleTextAttributes = [
.foregroundColor: UIColor.red
]
}
How would I do this for the current view only? I only want to set the navigation title color for the current view, not all views of the app.
The simplest case is as follows (you can also store/restore previous settings in some local var):
var body: some View {
NavigationView(){
List {
// Some content is here
}
.navigationBarTitle("Title")
.onAppear(perform: {
UINavigationBar.appearance().largeTitleTextAttributes = [
.foregroundColor: UIColor.red
]
})
.onDisappear(perform: {
UINavigationBar.appearance().largeTitleTextAttributes = nil
})
}
}
Here's a solution that sets attributes when a child view is shown, and resets them when the child view disappears:
import SwiftUI
struct ExampleView: View {
var body: some View {
NavigationView {
NavigationLink(destination: NestedView()) {
Label("Navigate", systemImage: "folder")
}
.navigationTitle("Home")
}
// This is important, it doesn't work without it.
.navigationViewStyle(.stack)
}
}
struct NestedView: View {
var body: some View {
ZStack {
NavigationControllerAccessor(viewWillAppear: { nav in
nav.navigationBar.largeTitleTextAttributes = [
.foregroundColor: UIColor.red
]
}, viewWillDisappear: { nav in
nav.navigationBar.largeTitleTextAttributes = nil
})
Text("In nested view")
}
.navigationTitle("Nested")
}
}
struct NavigationControllerAccessor: UIViewControllerRepresentable {
var viewWillAppear: (UINavigationController) -> Void
var viewWillDisappear: ((UINavigationController) -> Void)? = nil
private let proxyController = ViewController()
func makeUIViewController(context: UIViewControllerRepresentableContext<NavigationControllerAccessor>) -> UIViewController {
proxyController.viewWillAppearCallback = viewWillAppear
if let viewWillDisappear = viewWillDisappear {
proxyController.viewWillDisappearCallback = viewWillDisappear
}
return proxyController
}
func updateUIViewController(_ uiViewController: UIViewController, context: UIViewControllerRepresentableContext<NavigationControllerAccessor>) {}
private class ViewController: UIViewController {
var viewWillAppearCallback: (UINavigationController) -> Void = { _ in }
var viewWillDisappearCallback: (UINavigationController) -> Void = { _ in }
override func viewWillAppear(_ animated: Bool) {
super.viewWillAppear(animated)
if let nav = navigationController {
viewWillAppearCallback(nav)
}
}
override func viewWillDisappear(_ animated: Bool) {
super.viewWillDisappear(animated)
if let nav = navigationController {
viewWillDisappearCallback(nav)
}
}
}
}
struct ExampleView_Previews: PreviewProvider {
static var previews: some View {
ExampleView()
}
}
Demo:
Not sure do you have this issue now.
I have searched for this issue and find a great article about this, you could wrap the settings of navigation bar style as a view modifier.
Check this Link.
struct NavigationBarModifier: ViewModifier {
var backgroundColor: UIColor?
var titleColor: UIColor?
init(backgroundColor: UIColor?, titleColor: UIColor?) {
self.backgroundColor = backgroundColor
let coloredAppearance = UINavigationBarAppearance()
coloredAppearance.configureWithTransparentBackground()
coloredAppearance.backgroundColor = backgroundColor
coloredAppearance.titleTextAttributes = [.foregroundColor: titleColor ?? .white]
coloredAppearance.largeTitleTextAttributes = [.foregroundColor: titleColor ?? .white]
UINavigationBar.appearance().standardAppearance = coloredAppearance
UINavigationBar.appearance().compactAppearance = coloredAppearance
UINavigationBar.appearance().scrollEdgeAppearance = coloredAppearance
}
func body(content: Content) -> some View {
ZStack{
content
VStack {
GeometryReader { geometry in
Color(self.backgroundColor ?? .clear)
.frame(height: geometry.safeAreaInsets.top)
.edgesIgnoringSafeArea(.top)
Spacer()
}
}
}
}
}
extension View {
func navigationBarColor(backgroundColor: UIColor?, titleColor: UIColor?) -> some View {
self.modifier(NavigationBarModifier(backgroundColor: backgroundColor, titleColor: titleColor))
}
}
After that, apply like this:
.navigationBarColor(backgroundColor: .clear, titleColor: .white)
So when I make a list in SwiftUI, I get the master-detail split view for "free".
So for instance with this:
import SwiftUI
struct ContentView : View {
var people = ["Angela", "Juan", "Yeji"]
var body: some View {
NavigationView {
List {
ForEach(people, id: \.self) { person in
NavigationLink(destination: Text("Hello!")) {
Text(person)
}
}
}
Text("🤪")
}
}
}
#if DEBUG
struct ContentView_Previews : PreviewProvider {
static var previews: some View {
ContentView()
}
}
#endif
I get a splitView if an iPad simulator is in landscape, and the first detail screen is the emoji. But if people tap on a name, the detail view is "Hello!"
All that is great.
However, if I run the iPad in portrait, the user is greeted by the emoji, and then there is no indication that there is a list. You have to swipe from left to right to make the list appear from the side.
Does anyone know of a way to get even a navigation bar to appear that would let the user tap to see the list of items on the left? So that it's not a screen with the emoji only?
I would hate to leave a note that says "Swipe in from the left to see the list of files/people/whatever"
I remember UISplitViewController had a collapsed property that could be set. Is there anything like that here?
In Xcode 11 beta 3, Apple has added .navigationViewStyle(style:) to NavigationView.
Updated for Xcode 11 Beta 5.
create MasterView() & DetailsView().
struct MyMasterView: View {
var people = ["Angela", "Juan", "Yeji"]
var body: some View {
List {
ForEach(people, id: \.self) { person in
NavigationLink(destination: DetailsView()) {
Text(person)
}
}
}
}
}
struct DetailsView: View {
var body: some View {
Text("Hello world")
.font(.largeTitle)
}
}
inside my ContentView :
var body: some View {
NavigationView {
MyMasterView()
DetailsView()
}.navigationViewStyle(DoubleColumnNavigationViewStyle())
.padding()
}
Output:
For now, in Xcode 11.2.1 it is still nothing changed.
I had the same issue with SplitView on iPad and resolved it by adding padding like in Ketan Odedra response, but modified it a little:
var body: some View {
GeometryReader { geometry in
NavigationView {
MasterView()
DetailsView()
}
.navigationViewStyle(DoubleColumnNavigationViewStyle())
.padding(.leading, leadingPadding(geometry))
}
}
private func leadingPadding(_ geometry: GeometryProxy) -> CGFloat {
if UIDevice.current.userInterfaceIdiom == .pad {
return 0.5
}
return 0
}
This works perfectly in the simulator. But when I submit my app for review, it was rejected. This little hack doesn't work on the reviewer device. I don't have a real iPad, so I don't know what caused this. Try it, maybe it will work for you.
While it doesn't work for me, I requested help from Apple DTS.
They respond to me that for now, SwiftUI API can't fully simulate UIKit`s SplitViewController behavior. But there is a workaround.
You can create custom SplitView in SwiftUI:
struct SplitView<Master: View, Detail: View>: View {
var master: Master
var detail: Detail
init(#ViewBuilder master: () -> Master, #ViewBuilder detail: () -> Detail) {
self.master = master()
self.detail = detail()
}
var body: some View {
let viewControllers = [UIHostingController(rootView: master), UIHostingController(rootView: detail)]
return SplitViewController(viewControllers: viewControllers)
}
}
struct SplitViewController: UIViewControllerRepresentable {
var viewControllers: [UIViewController]
#Environment(\.splitViewPreferredDisplayMode) var preferredDisplayMode: UISplitViewController.DisplayMode
func makeUIViewController(context: Context) -> UISplitViewController {
return UISplitViewController()
}
func updateUIViewController(_ splitController: UISplitViewController, context: Context) {
splitController.preferredDisplayMode = preferredDisplayMode
splitController.viewControllers = viewControllers
}
}
struct PreferredDisplayModeKey : EnvironmentKey {
static var defaultValue: UISplitViewController.DisplayMode = .automatic
}
extension EnvironmentValues {
var splitViewPreferredDisplayMode: UISplitViewController.DisplayMode {
get { self[PreferredDisplayModeKey.self] }
set { self[PreferredDisplayModeKey.self] = newValue }
}
}
extension View {
/// Sets the preferred display mode for SplitView within the environment of self.
func splitViewPreferredDisplayMode(_ mode: UISplitViewController.DisplayMode) -> some View {
self.environment(\.splitViewPreferredDisplayMode, mode)
}
}
And then use it:
SplitView(master: {
MasterView()
}, detail: {
DetailView()
}).splitViewPreferredDisplayMode(.allVisible)
On an iPad, it works. But there is one issue (maybe more..).
This approach ruins navigation on iPhone because both MasterView and DetailView have their NavigationView.
UPDATE:
Finally, in Xcode 11.4 beta 2 they added a button in Navigation Bar that indicates hidden master view.
Minimal testing in the Simulator, but this should be close to a real solution. The idea is to use an EnvironmentObject to hold a published var on whether to use a double column NavigationStyle, or a single one, then have the NavigationView get recreated if that var changes.
The EnvironmentObject:
final class AppEnvironment: ObservableObject {
#Published var useSideBySide: Bool = false
}
In the Scene Delegate, set the variable at launch, then observe device rotations and possibly change it (the "1000" is not the correct value, starting point):
class SceneDelegate: UIResponder, UIWindowSceneDelegate {
var appEnvironment = AppEnvironment()
#objc
func orientationChanged() {
let bounds = UIScreen.main.nativeBounds
let orientation = UIDevice.current.orientation
// 1000 is a starting point, should be smallest height of a + size iPhone
if orientation.isLandscape && bounds.size.height > 1000 {
if appEnvironment.useSideBySide == false {
appEnvironment.useSideBySide = true
print("SIDE changed to TRUE")
}
} else if orientation.isPortrait && appEnvironment.useSideBySide == true {
print("SIDE changed to false")
appEnvironment.useSideBySide = false
}
}
func scene(_ scene: UIScene, willConnectTo session: UISceneSession, options connectionOptions: UIScene.ConnectionOptions) {
let contentView = ContentView()
if let windowScene = scene as? UIWindowScene {
let window = UIWindow(windowScene: windowScene)
window.rootViewController = UIHostingController(rootView: contentView.environmentObject(appEnvironment))
self.window = window
window.makeKeyAndVisible()
orientationChanged()
NotificationCenter.default.addObserver(self, selector: #selector(orientationChanged), name: UIDevice.orientationDidChangeNotification, object: nil)
UIDevice.current.beginGeneratingDeviceOrientationNotifications()
}
In the top level content view, where the NavigationView is created, use a custom modifier instead of using a navigationViewStyle directly:
struct ContentView: View {
#State private var dates = [Date]()
var body: some View {
NavigationView {
MV(dates: $dates)
DetailView()
}
.modifier( WTF() )
}
struct WTF: ViewModifier {
#EnvironmentObject var appEnvironment: AppEnvironment
func body(content: Content) -> some View {
Group {
if appEnvironment.useSideBySide == true {
content
.navigationViewStyle(DoubleColumnNavigationViewStyle())
} else {
content
.navigationViewStyle(StackNavigationViewStyle())
}
}
}
}
}
As mentioned earlier, just Simulator testing, but I tried launching in both orientations, rotating with Master showing, rotating with Detail showing, it all looks good to me.
For current version (iOS 13.0-13.3.x), you can use my code.
I use a UIViewUpdater to access the underlaying UIView and its UIViewController to adjust the bar item.
I think the UIViewUpdater way to solve this problem is the most Swifty and robust way, and you can use it to access and modify other UIView, UIViewController related UIKit mechanism.
ContentView.swift
import SwiftUI
struct ContentView : View {
var people = ["Angela", "Juan", "Yeji"]
var body: some View {
NavigationView {
List {
ForEach(people, id: \.self) { person in
NavigationLink(destination: DetailView()) { Text(person) }
}
}
InitialDetailView()
}
}
}
struct DetailView : View {
var body: some View {
Text("Hello!")
}
}
struct InitialDetailView : View {
var body: some View {
NavigationView {
Text("🤪")
.navigationBarTitle("", displayMode: .inline) // .inline is neccesary for showing the left button item
.updateUIViewController {
$0.splitViewController?.preferredDisplayMode = .primaryOverlay // for showing overlay at initial
$0.splitViewController?.preferredDisplayMode = .automatic
}
.displayModeButtonItem()
}.navigationViewStyle(StackNavigationViewStyle())
}
}
#if DEBUG
struct ContentView_Previews : PreviewProvider {
static var previews: some View {
ContentView()
}
}
#endif
Utility code for the solution. Put it in any Swift file for the project.
Utility.swift
// View decoration
public extension View {
func updateUIView(_ action: #escaping (UIView) -> Void) -> some View {
background(UIViewUpdater(action: action).opacity(0))
}
func updateUIViewController(_ action: #escaping (UIViewController) -> Void) -> some View {
updateUIView {
guard let viewController = $0.viewController else { return }
action(viewController)
}
}
func displayModeButtonItem(_ position: NavigationBarPostion = .left) -> some View {
updateUIViewController { $0.setDisplayModeButtonItem(position) }
}
}
// UpdateUIView
struct UIViewUpdater : UIViewRepresentable {
let action: (UIView) -> Void
typealias UIViewType = InnerUIView
func makeUIView(context: UIViewRepresentableContext<Self>) -> UIViewType {
UIViewType(action: action)
}
func updateUIView(_ uiView: UIViewType, context: UIViewRepresentableContext<Self>) {
// DispatchQueue.main.async { [action] in action(uiView) }
}
class InnerUIView : UIView {
let action: (UIView) -> Void
init(action: #escaping (UIView) -> Void) {
self.action = action
super.init(frame: .zero)
}
required init?(coder: NSCoder) {
fatalError("init(coder:) has not been implemented")
}
override func didMoveToWindow() {
super.didMoveToWindow()
update()
}
func update() {
action(self)
}
}
}
// UIView.viewController
public extension UIView {
var viewController: UIViewController? {
var i: UIResponder? = self
while i != nil {
if let vc = i as? UIViewController { return vc }
i = i?.next
}
return nil
}
}
// UIViewController.setDisplayModeButtonItem
public enum NavigationBarPostion {
case left
case right
}
public extension UIViewController {
func setDisplayModeButtonItem(_ position: NavigationBarPostion) {
guard let splitViewController = splitViewController else { return }
switch position {
case .left:
// keep safe to avoid replacing other left bar button item, e.g. navigation back
navigationItem.leftItemsSupplementBackButton = true
navigationItem.leftBarButtonItem = splitViewController.displayModeButtonItem
case .right:
navigationItem.rightBarButtonItem = splitViewController.displayModeButtonItem
}
}
}
import SwiftUI
var hostingController: UIViewController?
func showList() {
let split = hostingController?.children[0] as? UISplitViewController
UIView.animate(withDuration: 0.3, animations: {
split?.preferredDisplayMode = .primaryOverlay
}) { _ in
split?.preferredDisplayMode = .automatic
}
}
func hideList() {
let split = hostingController?.children[0] as? UISplitViewController
split?.preferredDisplayMode = .primaryHidden
}
// =====
struct Dest: View {
var person: String
var body: some View {
VStack {
Text("Hello! \(person)")
Button(action: showList) {
Image(systemName: "sidebar.left")
}
}
.onAppear(perform: hideList)
}
}
struct ContentView : View {
var people = ["Angela", "Juan", "Yeji"]
var body: some View {
NavigationView {
List {
ForEach(people, id: \.self) { person in
NavigationLink(destination: Dest(person: person)) {
Text(person)
}
}
}
VStack {
Text("🤪")
Button(action: showList) {
Image(systemName: "sidebar.left")
}
}
}
}
}
import PlaygroundSupport
hostingController = UIHostingController(rootView: ContentView())
PlaygroundPage.current.setLiveView(hostingController!)
At WWDC 2019, Apple announced a new "card-style" look for modal presentations, which brought along with it built-in gestures for dismissing modal view controllers by swiping down on the card. They also introduced the new isModalInPresentation property on UIViewController so that you can disallow this dismissal behavior if you so choose.
So far, though, I have found no way to emulate this behavior in SwiftUI. Using the .presentation(_ modal: Modal?), does not, as far as I can tell, allow you to disable the dismissal gestures in the same way. I also attempted putting the modal view controller inside a UIViewControllerRepresentable View, but that didn't seem to help either:
struct MyViewControllerView: UIViewControllerRepresentable {
func makeUIViewController(context: UIViewControllerRepresentableContext<MyViewControllerView>) -> UIHostingController<MyView> {
return UIHostingController(rootView: MyView())
}
func updateUIViewController(_ uiViewController: UIHostingController<MyView>, context: UIViewControllerRepresentableContext<MyViewControllerView>) {
uiViewController.isModalInPresentation = true
}
}
Even after presenting with .presentation(Modal(MyViewControllerView())) I was able to swipe down to dismiss the view. Is there currently any way to do this with existing SwiftUI constructs?
Update for iOS 15
As per pawello2222's answer below, this is now supported by the new interactiveDismissDisabled(_:) API.
struct ContentView: View {
#State private var showSheet = false
var body: some View {
Text("Content View")
.sheet(isPresented: $showSheet) {
Text("Sheet View")
.interactiveDismissDisabled(true)
}
}
}
Pre-iOS-15 answer
I wanted to do this as well, but couldn't find the solution anywhere. The answer that hijacks the drag gesture kinda works, but not when it's dismissed by scrolling a scroll view or form. The approach in the question is less hacky also, so I investigated it further.
For my use case I have a form in a sheet which ideally could be dismissed when there's no content, but has to be confirmed through a alert when there is content.
My solution for this problem:
struct ModalSheetTest: View {
#State private var showModally = false
#State private var showSheet = false
var body: some View {
Form {
Toggle(isOn: self.$showModally) {
Text("Modal")
}
Button(action: { self.showSheet = true}) {
Text("Show sheet")
}
}
.sheet(isPresented: $showSheet) {
Form {
Button(action: { self.showSheet = false }) {
Text("Hide me")
}
}
.presentation(isModal: self.showModally) {
print("Attempted to dismiss")
}
}
}
}
The state value showModally determines if it has to be showed modally. If so, dragging it down to dismiss will only trigger the closure which just prints "Attempted to dismiss" in the example, but can be used to show the alert to confirm dismissal.
struct ModalView<T: View>: UIViewControllerRepresentable {
let view: T
let isModal: Bool
let onDismissalAttempt: (()->())?
func makeUIViewController(context: Context) -> UIHostingController<T> {
UIHostingController(rootView: view)
}
func updateUIViewController(_ uiViewController: UIHostingController<T>, context: Context) {
context.coordinator.modalView = self
uiViewController.rootView = view
uiViewController.parent?.presentationController?.delegate = context.coordinator
}
func makeCoordinator() -> Coordinator {
Coordinator(self)
}
class Coordinator: NSObject, UIAdaptivePresentationControllerDelegate {
let modalView: ModalView
init(_ modalView: ModalView) {
self.modalView = modalView
}
func presentationControllerShouldDismiss(_ presentationController: UIPresentationController) -> Bool {
!modalView.isModal
}
func presentationControllerDidAttemptToDismiss(_ presentationController: UIPresentationController) {
modalView.onDismissalAttempt?()
}
}
}
extension View {
func presentation(isModal: Bool, onDismissalAttempt: (()->())? = nil) -> some View {
ModalView(view: self, isModal: isModal, onDismissalAttempt: onDismissalAttempt)
}
}
This is perfect for my use case, hope it helps you or someone else out as well.
By changing the gesture priority of any view you don't want to be dragged, you can prevent DragGesture on any view. For example for Modal it can be done as bellow:
Maybe it is not a best practice, but it works perfectly
struct ContentView: View {
#State var showModal = true
var body: some View {
Button(action: {
self.showModal.toggle()
}) {
Text("Show Modal")
}.sheet(isPresented: self.$showModal) {
ModalView()
}
}
}
struct ModalView : View {
#Environment(\.presentationMode) var presentationMode
let dg = DragGesture()
var body: some View {
ZStack {
Rectangle()
.fill(Color.white)
.frame(width: UIScreen.main.bounds.width, height: UIScreen.main.bounds.height)
.highPriorityGesture(dg)
Button("Dismiss Modal") {
self.presentationMode.wrappedValue.dismiss()
}
}
}
}
Note: This code has been edited for clarity and brevity.
Using a way to get the current window scene from here you can get the top view controller by this extension here from #Bobj-C
extension UIApplication {
func visibleViewController() -> UIViewController? {
guard let window = UIApplication.shared.windows.first(where: { $0.isKeyWindow }) else { return nil }
guard let rootViewController = window.rootViewController else { return nil }
return UIApplication.getVisibleViewControllerFrom(vc: rootViewController)
}
private static func getVisibleViewControllerFrom(vc:UIViewController) -> UIViewController {
if let navigationController = vc as? UINavigationController,
let visibleController = navigationController.visibleViewController {
return UIApplication.getVisibleViewControllerFrom( vc: visibleController )
} else if let tabBarController = vc as? UITabBarController,
let selectedTabController = tabBarController.selectedViewController {
return UIApplication.getVisibleViewControllerFrom(vc: selectedTabController )
} else {
if let presentedViewController = vc.presentedViewController {
return UIApplication.getVisibleViewControllerFrom(vc: presentedViewController)
} else {
return vc
}
}
}
}
and turn it into a view modifier like this:
struct DisableModalDismiss: ViewModifier {
let disabled: Bool
func body(content: Content) -> some View {
disableModalDismiss()
return AnyView(content)
}
func disableModalDismiss() {
guard let visibleController = UIApplication.shared.visibleViewController() else { return }
visibleController.isModalInPresentation = disabled
}
}
and use like:
struct ShowSheetView: View {
#State private var showSheet = true
var body: some View {
Text("Hello, World!")
.sheet(isPresented: $showSheet) {
TestView()
.modifier(DisableModalDismiss(disabled: true))
}
}
}
For everyone who has problems with #Guido's solution and NavigationView. Just combine the solution of #Guido and #SlimeBaron
class ModalHostingController<Content: View>: UIHostingController<Content>, UIAdaptivePresentationControllerDelegate {
var canDismissSheet = true
var onDismissalAttempt: (() -> ())?
override func willMove(toParent parent: UIViewController?) {
super.willMove(toParent: parent)
parent?.presentationController?.delegate = self
}
func presentationControllerShouldDismiss(_ presentationController: UIPresentationController) -> Bool {
canDismissSheet
}
func presentationControllerDidAttemptToDismiss(_ presentationController: UIPresentationController) {
onDismissalAttempt?()
}
}
struct ModalView<T: View>: UIViewControllerRepresentable {
let view: T
let canDismissSheet: Bool
let onDismissalAttempt: (() -> ())?
func makeUIViewController(context: Context) -> ModalHostingController<T> {
let controller = ModalHostingController(rootView: view)
controller.canDismissSheet = canDismissSheet
controller.onDismissalAttempt = onDismissalAttempt
return controller
}
func updateUIViewController(_ uiViewController: ModalHostingController<T>, context: Context) {
uiViewController.rootView = view
uiViewController.canDismissSheet = canDismissSheet
uiViewController.onDismissalAttempt = onDismissalAttempt
}
}
extension View {
func interactiveDismiss(canDismissSheet: Bool, onDismissalAttempt: (() -> ())? = nil) -> some View {
ModalView(
view: self,
canDismissSheet: canDismissSheet,
onDismissalAttempt: onDismissalAttempt
).edgesIgnoringSafeArea(.all)
}
}
Usage:
struct ContentView: View {
#State var isPresented = false
#State var canDismissSheet = false
var body: some View {
Button("Tap me") {
isPresented = true
}
.sheet(
isPresented: $isPresented,
content: {
NavigationView {
Text("Hello World")
}
.interactiveDismiss(canDismissSheet: canDismissSheet) {
print("attemptToDismissHandler")
}
}
)
}
}
As of iOS 14, you can use .fullScreenCover(isPresented:, content:) (Docs) instead of .sheet(isPresented:, content:) if you don't want the dismissal gestures.
struct FullScreenCoverPresenterView: View {
#State private var isPresenting = false
var body: some View {
Button("Present Full-Screen Cover") {
isPresenting.toggle()
}
.fullScreenCover(isPresented: $isPresenting) {
Text("Tap to Dismiss")
.onTapGesture {
isPresenting.toggle()
}
}
}
}
Note: fullScreenCover is unavailable on macOS, but it works well on iPhone and iPad.
Note: This solution doesn't allow you to enable the dismissal gesture when a certain condition is met. To enable and disable the dismissal gesture with a condition, see my other answer.
iOS 15+
Starting from iOS 15 we can use interactiveDismissDisabled:
func interactiveDismissDisabled(_ isDisabled: Bool = true) -> some View
We just need to attach it to the sheet:
struct ContentView: View {
#State private var showSheet = false
var body: some View {
Text("Content View")
.sheet(isPresented: $showSheet) {
Text("Sheet View")
.interactiveDismissDisabled(true)
}
}
}
If needed, you can also pass a variable to control when the sheet can be disabled:
.interactiveDismissDisabled(!userAcceptedTermsOfUse)
You can use this method to pass the content of the modal view for reuse.
Use NavigationView with gesture priority to disable dragging.
import SwiftUI
struct ModalView<Content: View>: View
{
#Environment(\.presentationMode) var presentationMode
let content: Content
let title: String
let dg = DragGesture()
init(title: String, #ViewBuilder content: #escaping () -> Content) {
self.content = content()
self.title = title
}
var body: some View
{
NavigationView
{
ZStack (alignment: .top)
{
self.content
}
.navigationBarTitleDisplayMode(.inline)
.toolbar(content: {
ToolbarItem(placement: .principal, content: {
Text(title)
})
ToolbarItem(placement: .navigationBarTrailing, content: {
Button("Done") {
self.presentationMode.wrappedValue.dismiss()
}
})
})
}
.highPriorityGesture(dg)
}
}
In Content View:
struct ContentView: View {
#State var showModal = true
var body: some View {
Button(action: {
self.showModal.toggle()
}) {
Text("Show Modal")
}.sheet(isPresented: self.$showModal) {
ModalView (title: "Title") {
Text("Prevent dismissal of modal view.")
}
}
}
}
Result!
We have created an extension to make controlling the modal dismission effortless, at https://gist.github.com/mobilinked/9b6086b3760bcf1e5432932dad0813c0
/// Example:
struct ContentView: View {
#State private var presenting = false
var body: some View {
VStack {
Button {
presenting = true
} label: {
Text("Present")
}
}
.sheet(isPresented: $presenting) {
ModalContent()
.allowAutoDismiss { false }
// or
// .allowAutoDismiss(false)
}
}
}
This solution worked for me on iPhone and iPad. It uses isModalInPresentation. From the docs:
The default value of this property is false. When you set it to true, UIKit ignores events outside the view controller's bounds and prevents the interactive dismissal of the view controller while it is onscreen.
Your attempt is close to what worked for me. The trick is setting isModalInPresentation on the hosting controller's parent in willMove(toParent:)
class MyHostingController<Content: View>: UIHostingController<Content> {
var canDismissSheet = true
override func willMove(toParent parent: UIViewController?) {
super.willMove(toParent: parent)
parent?.isModalInPresentation = !canDismissSheet
}
}
struct MyViewControllerView<Content: View>: UIViewControllerRepresentable {
let content: Content
let canDismissSheet: Bool
func makeUIViewController(context: Context) -> UIHostingController<Content> {
let viewController = MyHostingController(rootView: content)
viewController.canDismissSheet = canDismissSheet
return viewController
}
func updateUIViewController(_ uiViewController: UIHostingController<Content>, context: Context) {
uiViewController.parent?.isModalInPresentation = !canDismissSheet
}
}
it supports most of the iOS version
no need of making wrappers just do this
extension UINavigationController {
open override func viewDidLoad() {
super.viewDidLoad()
interactivePopGestureRecognizer?.isEnabled = false
interactivePopGestureRecognizer?.delegate = nil
}}