There and Back Again - Unity to Swift communication

There was some feedback in learning about starting a SharePlay session, about how to do it if your app was made using Unity.

You need a C# class that can send messages to swift. I call mine SwiftBridge:

public class SwiftBridge
{
[DllImport("__Internal")]
    private static extern void StartSharePlaySession();

public static void StartSharePlay()
    {
        try
        {
            StartSharePlaySession();
        }
        catch (Exception e)
        {
            D.Log(e.ToString());
        }
    }
}

In the Plugins folder I add SharePlayBridge.swift. But it's best to name it something relevant to your needs.

//Received messages from function above
@objc public class SharePlayBridge: NSObject {
    @_cdecl("StartSharePlaySession")
    public func StartSharePlaySession() {
        SharePlayBridge.startSession()
    }
}

@_silgen_name("UnitySendMessage")
func UnitySendMessage(_ obj: UnsafePointer<CChar>, _ method: UnsafePointer<CChar>, _ msg: UnsafePointer<CChar>)

//Sends messages to Unity
@objc public class SwiftUnityBridge: NSObject {
    @objc public static func sendToUnity(gameObject: String, method: String, message: String) {
        gameObject.withCString { gameObjectPtr in
            method.withCString { methodPtr in
                message.withCString { messagePtr in
                    UnitySendMessage(gameObjectPtr, methodPtr, messagePtr)
                }
            }
        }
    }
}

and then call this function whenever you want to send messages back to Unity.

SwiftUnityBridge.sendToUnity(gameObject: "[GAMEOBJECT_NAME]", method: "[METHOD_NAME_IN_MONOBEHAVIOUR_ON_GAMEOBJECT]", message: "[MESSAGE]")

If you are digging in to visionOS development, I can highly recommend the Step into Vision website and group. That's where a lot of the discussion for these posts originates from, so you can get sneak peeks, by heading over there.