Relevant image

最终的FirebaseUser fUser = FirebaseAuth.getInstance()。getCurrentUser();
DatabaseReference ref = FirebaseDatabase.getInstance()。getReference(“ Students”);

    final DatabaseReference refOne = FirebaseDatabase.getInstance().getReference("Users");



    ref.addValueEventListener(new ValueEventListener() {
        @Override
        public void onDataChange(@NonNull DataSnapshot dataSnapshot) {
            userList.clear();
            for (DataSnapshot ds:dataSnapshot.getChildren()){
                ModelUser modelUser = ds.getValue(ModelUser.class);



                {
                    userList.add(modelUser);
                }

                //adapter
                adapterUsers = new AdapterUser(Parent_LoginActivity.this, userList);
                //set adapter to recyclerview
                recyclerView.setAdapter(adapterUsers);
            }
        }

最佳答案

您可能需要先检索数据并将其插入列表,然后比较并检索所需的数据。 Firebase方法对查询的作用不及SQL。

10-08 14:10