java - 尝试在空对象引用 Firebase 上调用虚拟方法“boolean java.lang.String.equals(java.lang.Object)”

Question

对于这行代码，我一直收到相同的错误消息，我已经尝试了所有可能的方法来尝试解决这个问题，但根本没有任何效果。如果 if 语句If (!user.getid().equals(firebaseUser.getUid()))我被卡住并且变得如此沮丧，我再次尝试了一切。

public class UsersFragment extends Fragment {

    private  RecyclerView recyclerView;
    private List<User> mUsers;
    private UserAdapter userAdapter;

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {

        View view = inflater.inflate(R.layout.fragment_users, container, false);


        recyclerView = view.findViewById(R.id.recycler_view);
        recyclerView.setHasFixedSize(true);
        recyclerView.setLayoutManager(new LinearLayoutManager(getContext()));
        recyclerView.setAdapter(userAdapter);

        mUsers = new ArrayList<>();

        readUsers();

        return view; 
    }

    private void readUsers() {

        final FirebaseUser firebaseUser = FirebaseAuth.getInstance().getCurrentUser();

        DatabaseReference reference = FirebaseDatabase.getInstance().getReference("Users");

        reference.addValueEventListener(new ValueEventListener() {
            @Override
            public void onDataChange(@NonNull DataSnapshot snapshot) {
                mUsers.clear();
                for (DataSnapshot ignored : snapshot.getChildren()) {
                    User user = snapshot.getValue(User.class);


                    assert user != null;
                    assert firebaseUser != null;

                    if (!user.getId().equals(firebaseUser.getUid())) {
                        mUsers.add(user);
                    }

                }

                userAdapter = new UserAdapter(getContext(), mUsers, false);
                recyclerView.setAdapter(userAdapter);
            }

            @Override
            public void onCancelled(@NonNull DatabaseError error) {

            }
        });


    }

标签： javaandroidfirebase-realtime-databasefirebase-authentication