当我尝试从回收站视图调用user1时，此代码向我显示错误

Question

当我尝试从recyclerview调用user1时，它崩溃了，我想尝试解决它几个小时，但是如果仍然无法解决，那么如果您能帮助我，我会提出申请

private void readChats() {
        users = new ArrayList<>();
        reference = FirebaseDatabase.getInstance().getReference("teacher");

        reference.addValueEventListener(new ValueEventListener() {
            @Override
            public void onDataChange(@NonNull DataSnapshot dataSnapshot) {
                users.clear();

                for (DataSnapshot snapshot : dataSnapshot.getChildren()) {
                    User user = snapshot.getValue(User.class);

                    for (String id : usersList) {
                        if (user.getId().equals(id)) {
                            if (users.size() != 0) {
                                for (User user1 : users) {
                                    if (!user.getId().equals(user1.getId())) {
                                        users.add(user);
                                    }
                                }
                            }else {
                                users.add(user);
                            }
                        }
                    }
                }
                userAdapter = new UserAdapter(getContext(), users);
                recyclerView.setAdapter(userAdapter);
            }

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

            }
        });
    }

日志猫向我显示此代码for (User user1 : users)上的错误 预先感谢