How to pass data from SwiftUI to ViewController - ios

Question

hoping someone can help me with this, I am building an iOS app with Swift and SwiftUI that launches different Unity scenes with the click of different buttons. I have the Unity part working well thanks to some good tutorials but I am having trouble being able to change scene with different button clicks. The tutorials I have followed set up the Unity code in a view controller that is then launched from a navigation view. I can launch the view controller and change the sceneNumber to whichever one I want and it will load that scene. I can't find away to do that in a way that is set before I launch the view controller.
Here is my View where the LauncherView has two buttons that will launch the view controller, I would like to change which sceneNumber is sent to the ViewController. I also have the problem of when I go back in the app and click through again nothing is displaying. I think this is because the UnityBridge class is already created and in the background somewhere.
Any help would be greatly appreciated! Thanks.
Here is my view code:
var sceneNumber: String = ""
struct MyViewController: UIViewControllerRepresentable {
func makeUIViewController(context: Context) -> UIViewController {
let vc = UIViewController()
UnityBridge.getInstance().onReady = {
print("Unity is now ready!")
UnityBridge.getInstance().show(controller: vc)
let api = UnityBridge.getInstance().api
api.test(sceneNumber)
}
return vc
}
func updateUIViewController(_ viewController: UIViewController, context: Context) {}
}
struct ContentView: View {
var body: some View {
VStack{
MyViewController()
}
}
}
struct FirstView: View {
var body: some View {
NavigationView{
VStack{
NavigationLink(destination: ContentView()) { //+ code to set sceneNumber to "1"
Text("Launch Unity Scene 1")
}
Text("")
NavigationLink(destination: ContentView()) { //+code to set sceneNumber to "2"
Text("Launch Unity Scene 2")
}
}
}
}
}
And here is the UnityBridge class code:
import Foundation
import UnityFramework
import SwiftUI
class API: NativeCallsProtocol {
internal weak var bridge: UnityBridge!
/**
Function pointers to static functions declared in Unity
*/
private var testCallback: TestDelegate!
/**
Public API
*/
public func test(_ value: String) {
self.testCallback(value)
}
/**
Internal methods are called by Unity
*/
internal func onUnityStateChange(_ state: String) {
switch (state) {
case "ready":
self.bridge.unityGotReady()
default:
return
}
}
internal func onSetTestDelegate(_ delegate: TestDelegate!) {
self.testCallback = delegate
}
}
class UnityBridge: UIResponder, UIApplicationDelegate, UnityFrameworkListener {
private static var instance : UnityBridge?
internal(set) public var isReady: Bool = false
public var api: API
private let ufw: UnityFramework
public var view: UIView? {
get { return self.ufw.appController()?.rootView }
}
public var onReady: () -> () = {}
public static func getInstance() -> UnityBridge {
print("Hello1.1")
//UnityBridge.instance?.unload()
if UnityBridge.instance == nil {
print("Hello1.2")
UnityBridge.instance = UnityBridge()
}
print("Hello1.3")
return UnityBridge.instance!
}
private static func loadUnityFramework() -> UnityFramework? {
print("Hello2")
let bundlePath: String = Bundle.main.bundlePath + "/Frameworks/UnityFramework.framework"
let bundle = Bundle(path: bundlePath)
if bundle?.isLoaded == false {
bundle?.load()
}
let ufw = bundle?.principalClass?.getInstance()
if ufw?.appController() == nil {
let machineHeader = UnsafeMutablePointer<MachHeader>.allocate(capacity: 1)
machineHeader.pointee = _mh_execute_header
ufw!.setExecuteHeader(machineHeader)
}
return ufw
}
internal override init() {
print("Hello3")
self.ufw = UnityBridge.loadUnityFramework()!
self.ufw.setDataBundleId("com.unity3d.framework")
self.api = API()
super.init()
self.api.bridge = self
self.ufw.register(self)
FrameworkLibAPI.registerAPIforNativeCalls(self.api)
ufw.runEmbedded(withArgc: CommandLine.argc, argv: CommandLine.unsafeArgv, appLaunchOpts: nil)
}
public func show(controller: UIViewController) {
print("Hello4")
if self.isReady {
self.ufw.showUnityWindow()
}
if let view = self.view {
controller.view?.addSubview(view)
}
}
public func unload() {
print("Hello5")
self.ufw.unloadApplication()
}
internal func unityGotReady() {
print("Hello6")
self.isReady = true
onReady()
}
internal func unityDidUnload(_ notification: Notification!) {
print("Hello7")
ufw.unregisterFrameworkListener(self)
UnityBridge.instance = nil
}
}