Use loop to skip an item of a list in a StreamBuilder

Issue

I am retrieving a list of users with a Stream and I need to ignore the current user. I did this once with a Future List, but with StreamBuilder an error appears when defining the list of documents.

So here's what's working (Future):

Future<List<Users>> _getUsers() async {
    Firestore db = Firestore.instance;

    QuerySnapshot querySnapshot = await db
        .collection('users')
        .getDocuments();

    List<Users> usersList = [];
    for (DocumentSnapshot item in querySnapshot.documents) {
      var data = item.data;
      if (data["id"] == _userId) continue;

      Users user = Users();
      user.name = data["name"];
      user.username = data["username"];
      user.id = data["id"];

      usersList.add(user);
    }

    return usersList;
  }

And this is not working (Stream):

startConnecting() {
    return Expanded(
      child: StreamBuilder(
        stream:Firestore.instance.collection('users').snapshots(),
        builder: (context, snapshot) {
          if (!snapshot.hasData) {
            return Center(
              child: Text(
                "Nothing."
                ),
              ),
            );
          }
          return ListView.builder(
            padding: EdgeInsets.only(top: 10),
            scrollDirection: Axis.vertical,
            itemCount: snapshot.data.documents.length,
            itemBuilder: (context, index) =>
                _buildListUsers(context, snapshot.data.documents[index]),
          );
        },
      ),
    );
  }

Widget _buildListUsers(BuildContext context, DocumentSnapshot document) {
    List<Users> usersList = [];
    for (DocumentSnapshot item in document) {

In that last 'document' an error message appears: "The type 'DocumentSnapshot' used in the 'for' loop must implement Iterable."

      var data = item.data;
      if (data["id"] == _userId) continue;

      Users user = Users();
      user.name = document["name"];
      user.username = document["username"];
      user.id = document["id"];

      usersList.add(user);

      return ListTile(
        ...
      );
    }
  }

I looked for this error but did not find anything like it. It must be something simple that I'm missing.

Solution

You don't have to loop through a DocumentSnapshot, because as stated, it's not an iterable object, it's a single document. So change this:

Widget _buildListUsers(BuildContext context, DocumentSnapshot document) {
    List<Users> usersList = [];
    for (DocumentSnapshot item in document) {

To this:

Widget _buildListUsers(BuildContext context, DocumentSnapshot document) {
    List<Users> usersList = [];
    //for (DocumentSnapshot item in document) { ==> comment out this for loop
  var data = document.data;
    //keep your logic here as it

    //remove the closing curly brace at the end, because there is no more for loop.

To answer your second question in the comment, do this:

if (data["id"] != _userId) {

      Users user = Users();
      user.name = data["name"];
      user.username = data["username"];
      user.id = data["id"];

      usersList.add(user);
    }

Answered By - Huthaifa Muayyad