How to run unity game from iOS app

Setup

• Create unity project with any custom settings
• If running in iOS simulator
  • change the Target SDK under player settings to Simulator SDK
• Create build for iOS
• Create a new swift UI app from xcode
  • Run it to check if it works fine without any errors
• Create a new workspace from xcode
  • Open workspace
  • Right click on the left project navigation panel and click add files to <workspace-name>
  • Choose Unity-iPhone.xcodeproj from the unity build folder which we created earlier and select create groups for any added folders
  • Choose <swift-ui-app>.xcodeproj from the swift UI app folder which we created earlier and select create groups for any added folders
  • Now, we have both unity build and iOS app together in the xcode workspace

Integrate unity app with swift UI

• Add UnityFramework.framework in iOS app target. It is under Targets > General > Frameworks, Libraries, and Embedded Contenta

• Add Data folder to UnityFramwork. Select Data folder under the Unity project and on the right side panel, check the UnityFramework checkbox under Target Membership

• Add a new swift class to iOS project

  • Paste this below code inside that file

  import Foundation
  import UnityFramework
  
  class Unity: UIResponder, UIApplicationDelegate {
  
      static let shared = Unity()
  
      private let dataBundleId: String = "com.unity3d.framework"
      private let frameworkPath: String = "/Frameworks/UnityFramework.framework"
  
      private var ufw : UnityFramework?
      private var hostMainWindow : UIWindow?
  
      private var isInitialized: Bool {
          ufw?.appController() != nil
      }
  
      func show() {
          if isInitialized {
              showWindow()
          } else {
              initWindow()
          }
      }
  
      func setHostMainWindow(_ hostMainWindow: UIWindow?) {
          self.hostMainWindow = hostMainWindow
      }
  
      private func initWindow() {
          if isInitialized {
              showWindow()
              return
          }
  
          guard let ufw = loadUnityFramework() else {
              print("ERROR: Not able to load Unity")
              return unloadWindow()
          }
  
          self.ufw = ufw
          ufw.setDataBundleId(dataBundleId)
          ufw.register(self)
          ufw.runEmbedded(
              withArgc: CommandLine.argc,
              argv: CommandLine.unsafeArgv,
              appLaunchOpts: nil
          )
      }
  
      private func showWindow() {
          if isInitialized {
              ufw?.showUnityWindow()
          }
      }
  
      private func unloadWindow() {
          if isInitialized {
              ufw?.unloadApplication()
          }
      }
  
      private func loadUnityFramework() -> UnityFramework? {
          let bundlePath: String = Bundle.main.bundlePath + frameworkPath
  
          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
      }
  }
  
  extension Unity: UnityFrameworkListener {
  
      func unityDidUnload(_ notification: Notification!) {
          ufw?.unregisterFrameworkListener(self)
          ufw = nil
          hostMainWindow?.makeKeyAndVisible()
      }
  }

  • Replace ContentView.swift file with this below code

  import SwiftUI
  
  struct ContentView: View {
      var body: some View {
          VStack {
              Image(systemName: "globe")
                  .imageScale(.large)
                  .foregroundStyle(.tint)
              Text("Hello, world!")
              Button(action: {                        
                  Unity.shared.show()
                  }) {
                      Text("Launch Unity")
                  }
          }
          .padding()
      }
  }
  
  #Preview {
      ContentView()
  }

• Run the iOS target, that's all.

• Unity game should launch now by clicking the Launch Unity text in the iOS app.