I am looking for a good solution to take data from a child of children.

As You can see in my "users" database i have nodes with users uid's, and in this nodes i have stored users data such as avatar, username etc. but i have problem with getting data from example "followers" node - So far I have been creating a new OnChildAddedListener in main OnChildAddedListener (listener for "users" node) but I am 100% sure I am doing it wrong - among other things because I never know when all the data has been loaded.

Database Structure:

• Users (NODE)
  • User uid (NODE)
    • username (string)
    • avatar (string)
    • firstname (string)
    • lastname (string)
    • followers (NODE) <- How to get data from this node without making new OnChildListener
    • albums (NODE) <- Same as "followers"

The way I tried to do it

FirebaseDatabase database;
        DatabaseReference userReference;
        DatabaseReference userFollowersReference;

        String loggedUserUid = "uid"; // Logged User UID

        database = FirebaseDatabase.getInstance("url");
        userReference = database.getReference("users").child(loggedUserUid);
        userFollowersReference = database.getReference("users").child(loggedUserUid).child("followers");

        userReference.addChildEventListener(new ChildEventListener() {
            @Override
            public void onChildAdded(@NonNull DataSnapshot snapshot, @Nullable String previousChildName) {
                String username = snapshot.child("username").getValue(String.class);
                String avatar = snapshot.child("avatar").getValue(String.class);
            }
        });

        userFollowersReference.addChildEventListener(new ChildEventListener() {
            @Override
            public void onChildAdded(@NonNull DataSnapshot snapshot, @Nullable String previousChildName) {
                List<String> followers = new ArrayList<>();

                followers.add(snapshot.child("followerUid").getValue(String.class));
            }
        });

So - is there a simpler and a better looking way to not clutter the code and to know when all the needed data is loaded?

CodePudding user response：

The snapshot contains everything in the node where you attached the listener. You just need to dig into it to find all the data.

snapshot
    .child("username")
    .child("followers")
    .child("followerUid")
    .getValue(String.class);