Unity2D: Creating a Cross-Platform Multi-Player Game in Unity Error!

Question

i'm following this tutorial on raywenderlich to do with multiplayer, since Unity updated, they have added a new method for the participant lefting the event. So I am getting this error on Unity:

Assets/Script/Multiplayer/GPG Multiplayer/MultiplayerController.cs(8,14): error CS0738: MultiplayerController' does not implement interface member GooglePlayGames.BasicApi.Multiplayer.RealTimeMultiplayerListener.OnParticipantLeft(GooglePlayGames.BasicApi.Multiplayer.Participant)' and the best implementing candidate MultiplayerController.OnRoomSetupProgress(float)' return typevoid' does not match interface member return type `void'

Whilst following the tutorial, I saw that someone in the comment section had the same error as me and someone replied back, however I wasn't sure how I should implement it as he didn't really explain it in great and clear detail!I also do not know how to create my own OnParticipantLeft(Participant leavingPlayer) method, which is why I was following the tutorial!

Hmm... looks like since this tutorial was written, they've added a new method or two to that interface. Here's the new method they're expecting to see

/// /// Raises the participant left event. /// This is called during room setup if a player declines an invitation /// or leaves. The status of the participant can be inspected to determine /// the reason. If all players have left, the room is closed automatically. /// /// Participant that left void OnParticipantLeft(Participant participant); If you just want to get your project going again, you can add your own OnParticipantLeft(Participant leavingPlayer) method to your MultiplayerController object and have it print out a debug message or two.

In an actual game, you could probably use this to make sure, say, your lobby display doesn't get messed up if a player joins, then leaves while you're waiting for a third or fourth player to join.

So anyway does anyone know how to fix this error? Below is my code:

 using UnityEngine;
 using UnityEngine.SceneManagement;
 using System.Collections;
 using GooglePlayGames;
 using GooglePlayGames.BasicApi.Multiplayer;
 using System.Collections.Generic;

 public class MultiplayerController : RealTimeMultiplayerListener 
 {
public MPLobbyListener lobbyListener;
private static MultiplayerController _instance = null;
private uint minimumOpponents = 1;
private uint maximumOpponents = 1;
private uint gameVariation = 0;
private byte _protocolVersion = 1;
// Byte + Byte + 2 floats for position + 2 floats for velcocity + 1 float for rotZ
private int _updateMessageLength = 22;
private List<byte> _updateMessage;
public MPUpdateListener updateListener;



public string GetMyParticipantId() {
    return PlayGamesPlatform.Instance.RealTime.GetSelf().ParticipantId;
}

public List<Participant> GetAllPlayers() {
    return PlayGamesPlatform.Instance.RealTime.GetConnectedParticipants ();
}

private void StartMatchMaking() {
    PlayGamesPlatform.Instance.RealTime.CreateQuickGame (minimumOpponents, maximumOpponents, gameVariation, this);
}

private MultiplayerController() {
    _updateMessage = new List<byte>(_updateMessageLength);
PlayGamesPlatform.DebugLogEnabled = true;
    PlayGamesPlatform.Activate ();
}

private void ShowMPStatus(string message) {
    Debug.Log(message);
    if (lobbyListener != null) {
        lobbyListener.SetLobbyStatusMessage(message);
    }
}

public void SendMyUpdate(float posX, float posY, Vector2 velocity, float rotZ) {
    _updateMessage.Clear ();
    _updateMessage.Add (_protocolVersion);
    _updateMessage.Add ((byte)'U');
    _updateMessage.AddRange (System.BitConverter.GetBytes (posX));  
    _updateMessage.AddRange (System.BitConverter.GetBytes (posY));  
    _updateMessage.AddRange (System.BitConverter.GetBytes (velocity.x));
    _updateMessage.AddRange (System.BitConverter.GetBytes (velocity.y));
    _updateMessage.AddRange (System.BitConverter.GetBytes (rotZ));
    byte[] messageToSend = _updateMessage.ToArray(); 
    Debug.Log ("Sending my update message  " + messageToSend + " to all players in the room");
    PlayGamesPlatform.Instance.RealTime.SendMessageToAll (false, messageToSend);
}

public void SignInAndStartMPGame() {
    if (! PlayGamesPlatform.Instance.localUser.authenticated) {
        PlayGamesPlatform.Instance.localUser.Authenticate((bool success) => {
            if (success) {
                Debug.Log ("We're signed in! Welcome " + PlayGamesPlatform.Instance.localUser.userName);
                StartMatchMaking();
            } else {
                Debug.Log ("Oh... we're not signed in.");
            }
        });
    } else {
        Debug.Log ("You're already signed in.");
        StartMatchMaking();
    }
}

public void SignOut() {
    PlayGamesPlatform.Instance.SignOut ();
}

public bool IsAuthenticated() {
    return PlayGamesPlatform.Instance.localUser.authenticated;
}

public void TrySilentSignIn() {
    if (! PlayGamesPlatform.Instance.localUser.authenticated) {
        PlayGamesPlatform.Instance.Authenticate ((bool success) => {
            if (success) {
                Debug.Log ("Silently signed in! Welcome " + PlayGamesPlatform.Instance.localUser.userName);
            } else {
                Debug.Log ("Oh... we're not signed in.");
            }
        }, true);
    } else {
        Debug.Log("We're already signed in");
    }
}

public static MultiplayerController Instance {
    get {
        if (_instance == null) {
            _instance = new MultiplayerController();
        }
        return _instance;
    }
}

public void OnRoomSetupProgress (float percent)
{
    ShowMPStatus ("We are " + percent + "% done with setup");
}

public void OnRoomConnected (bool success)
{
    if (success) {
        ShowMPStatus ("We are connected to the room! I would probably start our game now.");
        lobbyListener.HideLobby();
        lobbyListener = null;
        SceneManager.LoadScene("MainGame");
    } else {
        ShowMPStatus ("Uh-oh. Encountered some error connecting to the room.");
    }
}

public void OnLeftRoom ()
{
    ShowMPStatus ("We have left the room. We should probably perform some clean-up tasks.");
}

public void OnPeersConnected (string[] participantIds)
{
    foreach (string participantID in participantIds) {
        ShowMPStatus ("Player " + participantID + " has joined.");
    }
}

public void OnPeersDisconnected (string[] participantIds)
{
    foreach (string participantID in participantIds) {
        ShowMPStatus ("Player " + participantID + " has left.");
    }
}

public void OnRealTimeMessageReceived (bool isReliable, string senderId, byte[] data)
{
    // We'll be doing more with this later...
    byte messageVersion = (byte)data[0];
    // Let's figure out what type of message this is.
    char messageType = (char)data[1];
    if (messageType == 'U' && data.Length == _updateMessageLength) { 
        float posX = System.BitConverter.ToSingle(data, 2);
        float posY = System.BitConverter.ToSingle(data, 6);
        float velX = System.BitConverter.ToSingle(data, 10);
        float velY = System.BitConverter.ToSingle(data, 14);
        float rotZ = System.BitConverter.ToSingle(data, 18);
        Debug.Log ("Player " + senderId + " is at (" + posX + ", " + posY + ") traveling (" + velX + ", " + velY + ") rotation " + rotZ);
        // We'd better tell our GameController about this.
        if (updateListener != null) {
            updateListener.UpdateReceived(senderId, posX, posY, velX, velY, rotZ);
           }
       }
   }
}

Answer 1

You're missing some members from the interface RealTimeMultiplayerListener. According to your error, you need to implement GooglePlayGames.BasicApi.Multiplayer.RealTimeMultiplayerListener.OnParticipantLeft(GooglePlayGames.BasicApi.Multiplayer.Participant)

You could fix it adding this code to your MultiplayerController:

public void OnParticipantLeft(Participant participant)
{
    // Your code for this case (log, message, etc)
}