Android Studio中的参数错误

Question

当我将mPostFef作为参数添加时，出现错误，我不知道它是什么意思：

我认为这可能不是编码的正确方法。预先感谢您的任何建议。

private RecyclerView mPostRV;
    private FirebaseRecyclerAdapter<Post, PostViewHolder> mPostAdapter;
    private DatabaseReference mPostRef;
private void initialiseScreen() {
    mPostRV = (RecyclerView) findViewById(R.id.post_rv);
    mPostRV.setLayoutManager(new LinearLayoutManager(MainActivity.this));
    mPostRef = FirebaseDatabase.getInstance().getReference(Constants.POSTS);
    setupAdapter();
}

private void setupAdapter() {
    mPostAdapter = new FirebaseRecyclerAdapter<Post, PostViewHolder>(
            Post.class,
            R.layout.item_layout_post,
            PostViewHolder.class,
            mPostRef
    ) {
        @Override
        protected void onBindViewHolder(PostViewHolder holder, int position, Post model) {

        }

        @NonNull
        @Override
        public PostViewHolder onCreateViewHolder(@NonNull ViewGroup viewGroup, int i) {
            return null;
        }
    }
}

public static class PostViewHolder extends RecyclerView.ViewHolder {
    public PostViewHolder(View itemView) {
        super(itemView);
    }
}