Unity - Firebase realtime database - Get my rank in leaderboard

Question

I have a mini-game with a leaderboard using firebase database realtime.

After I got list of user-score from firebase, I would like to get the score of the current user who was out of the list.

It's easy to get the score of the current user but how to know the rank in list which was OrderByChild("score").

This is the code to get the leaderboard.

List<UserScore> leaderBoard = new List<UserScore>();
FirebaseDatabase.DefaultInstance
                .GetReference("user-scores")
                .OrderByChild("score")
                .LimitToLast(10)
                .GetValueAsync()
                .ContinueWith(task =>
        {
            if (task.IsFaulted)
            {
                Debug.Log("Fail To Load");
            }
            else if (task.IsCompleted)
            {
                DataSnapshot snapshot = task.Result;
                foreach (DataSnapshot h in snapshot.Children)
                {
                    UserScore userScore = new UserScore(h.Child("uid").Value.ToString(), h.Child("name").Value.ToString(), h.Child("photo").Value.ToString(),int.Parse(h.Child("score").Value.ToString()));
                    leaderBoard.Add(userScore);
                }
            }
        });

Answer 1

Try this for find user-rank in leaderboard.this works for me

sample image after code

    email_arrayList = new ArrayList();

    var currentUser = FirebaseAuth.DefaultInstance.CurrentUser;

    int rank = 0;
     playerId = currentUser.UserId;
     Debug.Log(playerId);

    FirebaseDatabase.DefaultInstance.GetReference("users").ValueChanged += FirebaseSaveLoadScript_ValueChanged;

    FirebaseDatabase.DefaultInstance
      .GetReference("users").OrderByChild("userScore")
      .ValueChanged += (object sender2, ValueChangedEventArgs e2) => {
          if (e2.DatabaseError != null)
          {
              Debug.LogError(e2.DatabaseError.Message);
              return;
          }
          Debug.Log("Received values for Leaders.");
          string title = leaderBoard[0].ToString();
          leaderBoard.Clear();
          leaderBoard.Add(title);
          if (e2.Snapshot != null && e2.Snapshot.ChildrenCount > 0)
          {
              foreach (var childSnapshot in e2.Snapshot.Children)
              {
                  if (childSnapshot.Child("userScore") == null
                || childSnapshot.Child("userScore").Value == null)
                  {
                      Debug.LogError("Bad data in sample.  Did you forget to call SetEditorDatabaseUrl with your project id?");
                      break;
                  }
                  else
                  {
                      Debug.Log("Leaders entry : " +
                    childSnapshot.Child("userEmail").Value.ToString() + " - " +
                    childSnapshot.Child("userScore").Value.ToString());

                      email_arrayList.Add(childSnapshot.Child("userEmail").Value.ToString());

                      leaderBoard.Insert(1, childSnapshot.Child("userScore").Value.ToString()
                    + "  " + childSnapshot.Child("userEmail").Value.ToString());

                      displayScores.text = "";
                      foreach (string item in leaderBoard)
                      {
                          displayScores.text += "\n" + item;

                      }
                  }

              }
          }

          email_arrayList.Reverse();
          foreach (string obj in email_arrayList)
          {
              rank++;
              if (obj == currentUser.Email)
              {
                  int rank_final = rank;
                  Debug.Log("I'm number " + rank_final + " in the rankings");
                  userRank.text = "Your Rank is " + rank_final;
                  rank = 0;
                  break;
              }

              Debug.Log(obj);

          }

      };

Answer 2

how to know my rank

That depends a bit on who "my" is. But say you have the UID of the current user in a variable uid. You can then determine their rank in this top 10 with:

int rank = 0;
foreach (DataSnapshot h in snapshot.Children)
{
    rank = rank + 1;
    UserScore userScore = new UserScore(
      h.Child("uid").Value.ToString(), 
      h.Child("name").Value.ToString(), 
      h.Child("photo").Value.ToString(),
      int.Parse(h.Child("score").Value.ToString()));
    leaderBoard.Add(userScore);
    if (h.Child("uid").Value.ToString() == uid) {
      Debug.Log("I'm number "+rank+" in the rankings");
    }
}