How to get Firebase database saved data according to date?

Question

I stored my data on Firebase according to auto-created ID. But now I need to get only today's added data from the database and populate a recycle view with it.

Answer 1

I assume branch users storing users information. You can add child event listener to branch users to get users as follows in your activity or fragment.

private ArrayList<User> userArray = new ArrayList<>();
private DatabaseReference mDatabase;
mDatabase = FirebaseDatabase.getInstance().getReference().getChild("users");

ChildEventListener childEventListener = new ChildEventListener() {
    @Override
    public void onChildAdded(DataSnapshot dataSnapshot, String previousChildName) {
        User user = dataSnapshot.getValue(User.class);
        if(user.getDate().equals(today)){
           userArray .add(user);
        }
    }

    @Override
    public void onChildChanged(DataSnapshot dataSnapshot, String previousChildName) {
       //do somethings
    }

    @Override
    public void onChildRemoved(DataSnapshot dataSnapshot) {
       //...
    }

    @Override
    public void onChildMoved(DataSnapshot dataSnapshot, String previousChildName) {
       //...
    }

    @Override
    public void onCancelled(DatabaseError databaseError) {
       //...
    }
};

Inside activity/fragment method, add the listener to your reference:

ref.addChildEventListener(childEventListener);

The array will be filled out with data from branch users. For more information how to work with list in firebase: https://firebase.google.com/docs/database/android/lists-of-data