Currently I'm the one not getting it.
Problem:
Trying to connect to a View Method from a Scene Delegate e.g.:
class SceneDelegate: UIResponder, UIWindowSceneDelegate {
var window: UIWindow?
...
func scene(_ scene: UIScene, continue userActivity: NSUserActivity) {
// guard let contentView = ???? as? ContentView else { return }
// contentView.callMethod(parameter: true)
}
}
struct ContentView: View {
var body: some View {
...
}
func callMethode(parameter: Bool) {
print("called")
}
}
Any clue how to connect to the View and call a method in-between?
thx
Jo
This is counter to the design of the SwiftUI framework. You should not have any persistent view around to call methods on. Instead, views are created and displayed as needed in response to your app's state changing.
For example, if your SceneDelegate had a reference to an instance of a model class, and your view depended on that model, you could modify the model in scene(_:continue:) and your view would update automatically.
If you can provide more specifics on what you're attempting to do, I may be able to give a more specific answer.
Many thanks. Fully understood... Will read the docs...
So is this a possible way as an example:
class SceneDelegate: UIResponder, UIWindowSceneDelegate {
var window: UIWindow?
let activity = UserActivityManager()
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(activity))
self.window = window
window.makeKeyAndVisible()
if let userActvity = connectionOptions.userActivities.first {
guard let title = userActvity.title else { return }
activity.doAction(action: title)
}
}
}
func scene(_ scene: UIScene, continue userActivity: NSUserActivity) {
guard let title = userActivity.title else { return }
activity.doAction(action: title)
}
}
Related
i tried to make a view like bellow in SwiftUi without any success Customized info window swift ui
Since this question doesn't have too much detail, I will be going off of some assumptions. First, I am assuming that you are calling the MapView through a UIViewControllerRepresentable.
I am not too familiar with the Google Maps SDK, but this is possible through the GMSMapViewDelegate Methods. After implementing the proper GMSMapViewDelegate method, you can use ZStacks to present the image that you would like to show.
For example:
struct MapView: UIViewControllerRepresentable {
var parentView: ContentView
func makeUIViewController(context: Context) {
let mapView = GMSMapView()
return mapView
}
func updateUIViewController(_ uiViewController: GMSMapView, context: Context) {
}
func makeCoordinator() -> Coordinator {
return Coordinator(self)
}
class Coordinator: NSObject, GMSMapViewDelegate {
var parent: MapView
init(_ parent: MapView) {
self.parent = parent
}
//Use the proper Google Maps Delegate method to find out if a marker was tapped and then show the image by doing: parent.parentView.isShowingInformationImage = true.
}
}
In your SwiftUI view that you would like to put this MapView in, you can do the following:
struct ContentView: View {
#State var isShowingInformationImage = false
var body: some View {
ZStack {
if isShowingInformationImage {
//Call the View containing the image
}
MapView(parentView: self)
}
}
}
I have a UI where you can navigate/push views like this:
AView -> BView -> CView -> DView
I want to pop a couple of views (get to BView from DView) instead of placing a new view (BView) on top of existing stack and I found the way to do this:
(UIApplication.shared.connectedScenes.first?.delegate as?
SceneDelegate)?.toBView()
What I don't understand is why does it call CView's init() when I try to return from DView to BView?
Here's the output i get in debug console:
AView init
BView init
CView init
DView init
contract.
button pressed
BView init
**CView init**
Why does it call CView's init() and how to avoid this behaviour?
AView.swift:
import SwiftUI
struct AView: View {
init() {
print("AView init")
}
var body: some View {
NavigationView {
VStack {
NavigationLink(destination: BView()) {
Text("This is View A, now go to View B.")
}
}
}
}
}
struct BView: View {
init() {
print("BView init")
}
var body: some View {
NavigationLink(destination: CView()) {
Text("This is View B, now go to View C.")
}
}
}
struct CView: View {
init() {
print("CView init")
}
var body: some View {
NavigationLink(destination: DView()) {
Text("This is View C, now go to View D.")
}
}
}
struct DView: View {
init() {
print("DView init")
}
var body: some View {
Button(action: {
print("button pressed")
(UIApplication.shared.connectedScenes.first?.delegate as? SceneDelegate)?.toBView()
},
label: {
Text("Back!")
})
}
}
SceneDelegate.swift:
import UIKit
import SwiftUI
class SceneDelegate: UIResponder, UIWindowSceneDelegate {
var window: UIWindow?
func scene(_ scene: UIScene, willConnectTo session: UISceneSession, options connectionOptions: UIScene.ConnectionOptions) {
// Create the SwiftUI view that provides the window contents.
let aView = AView()
// Use a UIHostingController as window root view controller.
if let windowScene = scene as? UIWindowScene {
let window = UIWindow(windowScene: windowScene)
window.rootViewController = UIHostingController(rootView: AView)
self.window = window
window.makeKeyAndVisible()
}
}
func toBView() {
let bView = BView()
window?.rootViewController = UIHostingController(rootView: bView)
}
}
This behavior is not wrong. If you start your app and display AView you will see in the console that it prints init from A and B.
It's because BView() is already initialized in your AView, even though you haven't activated the NavigationLink.
NavigationLink(destination: BView()) {
So this behavior is not specific to your pop back action, happens already at the beginning. See this solution from Asperi regarding multiple init() aswell, if you are concerned about calling init() more than once
I did a exmaple long time ago how to send a simple message from an iPhone to a Apple Watch using Swift:
import UIKit
import WatchConnectivity
class ViewController: UIViewController, WCSessionDelegate {
// MARK: Outlets
#IBOutlet weak var textField: UITextField!
// MARK: Variables
var wcSession : WCSession! = nil
// MARK: Overrides
override func viewDidLoad() {
super.viewDidLoad()
wcSession = WCSession.default
wcSession.delegate = self
wcSession.activate()
}
// MARK: Button Actions
#IBAction func sendText(_ sender: Any) {
let txt = textField.text!
let message = ["message":txt]
wcSession.sendMessage(message, replyHandler: nil) { (error) in
print(error.localizedDescription)
}
}
// MARK: WCSession Methods
func session(_ session: WCSession, activationDidCompleteWith activationState: WCSessionActivationState, error: Error?) {
// Code
}
func sessionDidBecomeInactive(_ session: WCSession) {
// Code
}
func sessionDidDeactivate(_ session: WCSession) {
// Code
}
}
Now I'm trying to do the same using SwiftUI but no success so far.
Can anyone help with this problem?
I just need to know how to use the WCSession Class and the WCSessionDelegate with SwiftUI.
Thanks
I just had the same question as you and I figured it out:
First you need to implement a class that conforms to WCSessionDelegate. I like to use a separate class for that:
import WatchConnectivity
class ConnectivityProvider: NSObject, WCSessionDelegate {
private let session: WCSession
init(session: WCSession = .default) {
self.session = session
super.init()
self.session.delegate = self
}
func send(message: [String:Any]) -> Void {
session.sendMessage(message, replyHandler: nil) { (error) in
print(error.localizedDescription)
}
}
func session(_ session: WCSession, activationDidCompleteWith activationState: WCSessionActivationState, error: Error?) {
// code
}
func sessionDidBecomeInactive(_ session: WCSession) {
// code
}
func sessionDidDeactivate(_ session: WCSession) {
// code
}
}
Now you need a ViewModel that takes your ConnectivityProvider as an argument. The ViewModel will be responsible for the connection of your View and the ConnectivityProvider. It also holds the value for the Textfield that later gets defined inside your View.
import SwiftUI
final class ViewModel: ObservableObject {
private(set) var connectivityProvider: ConnectivityProvider
var textFieldValue: String = ""
init(connectivityProvider: ConnectivityProvider) {
self.connectivityProvider = connectivityProvider
}
func sendMessage() -> Void {
let txt = textFieldValue
let message = ["message":txt]
connectivityProvider.send(message: message)
}
}
Now you can build a simple View that consists of a Textfield and a Button. Your View will be dependent on your ViewModel that you just defined.
import SwiftUI
struct ContentView: View {
#ObservedObject var viewModel: ViewModel
var body: some View {
VStack {
TextField("Message Content", text: $viewModel.textFieldValue)
Button(action: {
self.viewModel.sendMessage()
}) {
Text("Send Message")
}
}
}
}
Last but not least you need to combine your ConnectivityProvider, ViewModel and View inside of your SceneDelegate:
let viewModel = ViewModel(connectivityProvider: ConnectivityProvider())
let contentView = ContentView(viewModel: viewModel)
...
window.rootViewController = UIHostingController(rootView: contentView)
==================================
Update: How to activate the Session?
First add a new function to your ConnectivityProvider that activates the session:
class ConnectivityProvider: NSObject, WCSessionDelegate {
...
func connect() {
guard WCSession.isSupported() else {
print("WCSession is not supported")
return
}
session.activate()
}
...
}
Now you can call the connect function whenever you need your WCSession to be connected. You should be able to connect it everywhere, like in your SceneDelegate, inside your ViewModel, or even directly inside of the init of your ConnectivityProvider:
ConnectivityProvider init:
class ConnectivityProvider: NSObject, WCSessionDelegate {
private let session: WCSession
init(session: WCSession = .default) {
self.session = session
super.init()
self.session.delegate = self
self.connect()
}
...
}
ViewModel:
import SwiftUI
final class ViewModel: ObservableObject {
private(set) var connectivityProvider: ConnectivityProvider
var textFieldValue: String = ""
init(connectivityProvider: ConnectivityProvider) {
self.connectivityProvider = connectivityProvider
self.connectivityProvider.connect()
}
func sendMessage() -> Void {
let txt = textFieldValue
let message = ["message":txt]
connectivityProvider.send(message: message)
}
}
SceneDelegate:
let connectivityProvider = ConnectivityProvider()
connectivityProvider.connect()
let viewModel = ViewModel(connectivityProvider: connectivityProvider)
let contentView = ContentView(viewModel: viewModel)
...
window.rootViewController = UIHostingController(rootView: contentView)
So I have a ParentView, which has a NavigationLink, leading to a UIViewControllerRepresentable-conforming PageViewController.
Now that ParentView also has some subscription on some publisher. Whenever that one is fired, not only will the ParentView redraw all its content (which it should), it will also re-initialize the (already presenting) PageViewController.
That leads to stuttering/glitching, because the PageViewController is already presenting and using the controllers that are continually being resetted.
Below is the ParentView and PageViewController (without the Coordinator stuff), both is pretty vanilla. The commented guard line is a hack I tried to prevent it from updating if displayed already. It helps but it's still stuttering on every swipe.
So the question is: How can we prevent the updating of a presented ViewController-wrapped-View when its presenting View is redrawn?
struct ParentView: View {
#Binding var something: Bool
var body: some View {
NavigationLink(destination: PageViewController(controllers: controllers)) {
Text("Push me")
}
}
}
final class PageViewController: UIViewControllerRepresentable {
var controllers: [UIViewController]
private var currentPage = 0
init(controllers: [UIViewController]) {
self.controllers = controllers
}
func makeCoordinator() -> Coordinator {
Coordinator(self)
}
func makeUIViewController(context: Context) -> UIPageViewController {
let pageViewController = UIPageViewController(
transitionStyle: .scroll,
navigationOrientation: .horizontal)
pageViewController.dataSource = context.coordinator
pageViewController.delegate = context.coordinator
return pageViewController
}
func updateUIViewController(_ pageViewController: UIPageViewController, context: Context) {
// I tried this: guard pageViewController.viewControllers!.isEmpty else { return }
pageViewController.setViewControllers(
[controllers[currentPage]], direction: .forward, animated: true)
}
}
If your controllers don't change after being displayed once, you can simply call:
pageViewController.setViewControllers([controllers[currentPage]], direction: .forward, animated: true)
from the makeUIViewController(context:) function instead of the updateUIViewController(:) function.
I want to launch a View as a standalone View without the navigation hierarchy. The reason that I don't want to use a NavigationButton is that I don't want the user to return to the calling form.
I have tried the following approach that is similar to how the first view is launched in ScenceDelegate but nothing happens:
let appDelegate = UIApplication.shared.delegate as! AppDelegate
let window = appDelegate.getNewWindow()
window.rootViewController = UIHostingController(rootView: NewView())
window.makeKeyAndVisible()
I have a legitimate reason not to use the navigation UI, I'm leaving the explanation out to keep this short. I'm avoiding Storyboards to keep this as a simple as possible.
Thank you for any solution suggestions.
This is how I accomplished loading a new root View.
I added the following to the AppDelegate code
#UIApplicationMain
class AppDelegate: UIResponder, UIApplicationDelegate {
var window: UIWindow?
...
func loadNewRootSwiftUIView(rootViewController: UIViewController)
{
let window = UIWindow(frame: UIScreen.main.bounds)
window.rootViewController = rootViewController
self.window = window
window.makeKeyAndVisible()
}
}
And placed the following in my form:
struct LaunchView : View {
var body: some View {
VStack {
Button(
action: {
LaunchLoginView()
},
label: {
Text("Login")
}
)
}
}
}
func LaunchLoginView(){
let appDelegate = UIApplication.shared.delegate as! AppDelegate
let vContoller = UIHostingController(rootView: LoginView())
appDelegate.loadNewRootSwiftUIView(rootViewController: vContoller)
}