How can I get and display the amount of comments each post have? Flutter/Firebase

I'm trying to display the amount of comments every post has. Currently, the like count works so I tried to do something similar to what the likeCount function was doing. Once that didn't work, I went searching online everywhere to see if there were any other solutions, so far nothing has worked for me. This is what I have.

This is the function I think is having the problem. I tested adding a comment and it didn't write to Firebase.

getUserCommentCount() async {
    bool commented = comments[currentOnlineUserId] == true;
    if (commented) {
      postsReference
          .document(ownerId)
          .collection("usersPosts")
          .document(postId)
          .updateData({"commented.$currentOnlineUserId": true});

      setState(() {
        //print(commentCount);
        commentCount = commentCount + 1;
        commented = true;
        comments[currentOnlineUserId] = true;
      });
    }
  }

int getTotalNumberOfLikes(likes) {
    if (likes == null) {
      return 0;
    }
    int counter = 0;
    likes.values.forEach((eachValue) {
      {
        counter = counter + 1;
      }
    });
    return counter;
  }

  int getTotalNumberOfComments(comments) {
    if (comments == null) {
      return 0;
    }
    int counter = 0;
    comments.values.forEach((eachValue) {
      {
        counter = counter + 1;
      }
    });
    return counter;
  }

This is my function that adds and subtracts the likes. It works perfectly

controlUserLikePost() {
    bool _liked = likes[currentOnlineUserId] == true;

    if (_liked) {
      postsReference
          .document(ownerId)
          .collection("usersPosts")
          .document(postId)
          .updateData({"likes.$currentOnlineUserId": false});

      removeLike();

      setState(() {
        likeCount = likeCount - 1;
        isLiked = false;
        likes[currentOnlineUserId] = false;
      });
    } else if (!_liked) {
      postsReference
          .document(ownerId)
          .collection("usersPosts")
          .document(postId)
          .updateData({"likes.$currentOnlineUserId": true});

      addLike();

      setState(() {
        likeCount = likeCount + 1;
        isLiked = true;
        likes[currentOnlineUserId] = true;
        showHeart = true;
      });
      Timer(Duration(milliseconds: 800), () {
        setState(() {
          showHeart = false;
        });
      });
    }
  }

And this is how the likeCount and commentCount are called. The likeCount works correctly. CommentCount just shows 0 comments

Row(
          children: <Widget>[
            Container(
              margin: EdgeInsets.only(left: 15.0),
              child: Text(
                "$likeCount likes",
                style:
                    TextStyle(color: Colors.black, fontWeight: FontWeight.bold),
              ),
            ),
          ],
        ),
        Row(
          children: <Widget>[
            Container(
              margin: EdgeInsets.only(left: 15.0),
              child: Text(
                "$commentCount comments",
                style:
                    TextStyle(color: Colors.black, fontWeight: FontWeight.bold),
              ),
            ),
          ],
        ),

Any help would be much appreciated! Thanks