Question

我怎样才能查看帖子，只能从朋友那里查看？

在这个例子中，我想在RecyclerView中只显示我朋友的帖子。在这种情况下，用户15（当然是几个朋友，我只举一个例子）

结构 - 数据库：

USERS
-user01 (current user)
-name: John
-age: 20
--friends
----user10
----user15

-POSTS
--idpost_98685754
---user_post: user15
---title_post: Title
---photo: link

-posts
--idpost_41254d4554s1
---user_post: user40
---title_post: Title
---photo: link

-posts
--idpost_121221sss1
---user_post: user15
---title_post: Title 2
---photo: link 2

-posts
--idpost_9865565555
---user_post: user15
---title_post: Title 3
---photo: link 3

我目前只使用documentation中解释的简单顺序和限制功能。这是我第一次需要这样做。

编辑：

CODE - FRAGMENT：

/*Firebase*/
mDb = FirebaseFirestore.getInstance();
mQuery = mDb.collection("Posts");
Query mQueryNew = mQuery.orderBy("timestamp", Query.Direction.DESCENDING);



/* Recycler */
mCardFeedList = (RecyclerView) view.findViewById(id.cardFeedUser_list);
mCardFeedList.setHasFixedSize(true);
mCardFeedList.setItemViewCacheSize(20);
mCardFeedList.setDrawingCacheEnabled(true);


mAdapter = new PostsAdapter(mQueryNew, this){

    @Override
    protected void onDataChanged() {

        if (getItemCount() == 0) {
            mCardFeedList.setVisibility(View.GONE);


        } else {
            mCardFeedList.setVisibility(View.VISIBLE);

        }


    }
};

llmanager = new LinearLayoutManager(getActivity());
mCardFeedList.setLayoutManager(llmanager);
mCardFeedList.setAdapter(mAdapter);


/*START*/
if (mAdapter != null) {
    mAdapter.startListening();

}

ADAPTER：

public class PostsAdapter extends FirestoreAdapter<PostsAdapter.ViewHolder> {


    public interface OnPostsListner{

        void onPostSelected(DocumentSnapshot post);
        void onLikeSelected(DocumentSnapshot like);
        void onCurtidasSelected(DocumentSnapshot curtidas);
        void onFotoSelected(DocumentSnapshot foto);
        void onCommentsSelected(DocumentSnapshot coments);


    }


    private OnPostsListner mListner;
    public PostsAdapter (Query query, OnPostsListner listner){

        super(query);
        mListner = listner;

    }


    @Override
    public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        LayoutInflater inflater = LayoutInflater.from(parent.getContext());
        return new ViewHolder(inflater.inflate(R.layout.card_feed_user_row, parent, false));

    }

    @Override
    public void onBindViewHolder(ViewHolder holder, int position) {
        holder.bind(getSnapshot(position), mListner);
    }


    static class ViewHolder extends RecyclerView.ViewHolder {

        private Boolean mIsliked = false;

        @BindView(R.id.tvCardFeedUser_nome)
        TextView nomeUser;

        @BindView(R.id.tvCardFeedUser_horario)
        TextView horaFeed;

        @BindView(R.id.tvCardFeedUser_desc)
        TextView descFeed;

        @BindView(R.id.ivCardFeedUser_image)
        ImageView imageFeed;

        @BindView(R.id.secaoLike)
        LinearLayout curtir;

        @BindView(R.id.secaoComments)
        LinearLayout comentarios;

        @BindView(R.id.tv_card_feed_linear_curtidas)
        LinearLayout linear_curtidas;

        @BindView(R.id.idBtnLike)
        TextView btnLike;

        @BindView(R.id.tv_card_feed_numero_curtidas)
        TextView curtidas;

        @BindView(R.id.tv_card_feed_nome_curtida)
        TextView nome_curtidas;



        public ViewHolder(View itemView) {
            super(itemView);
            ButterKnife.bind(this, itemView);


        }


        public void bind(final DocumentSnapshot snapshot,
                         final OnPostsListner listener) {

            final Posts ref = snapshot.toObject(Posts.class);
            FirebaseFirestore db = FirebaseFirestore.getInstance();
            FirebaseAuth mAuth = FirebaseAuth.getInstance();
            final FirebaseUser mCurrentUser = mAuth.getCurrentUser();


            nomeUser.setText(ref.getNome_user());
            descFeed.setText(ref.getDesc());
            //Foto
            Picasso.with(itemView.getContext()).load(ref.getImage()).placeholder(R.drawable.bck_padrao).networkPolicy(NetworkPolicy.OFFLINE).into(imageFeed, new Callback() {
                @Override
                public void onSuccess() {

                }

                @Override
                public void onError() {

                    Picasso.with(itemView.getContext()).load(ref.getImage()).placeholder(R.drawable.bck_padrao).into(imageFeed);

                }
            });

            SimpleDateFormat formatter = new SimpleDateFormat("dd/M/yy HH:mm");
            String novaData = formatter.format(ref.getTimestamp());
            horaFeed.setText(novaData);

            /*CLICKS*/
            curtir.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View view) {

                    if (listener != null) {
                        listener.onLikeSelected(snapshot);

                    }

                }
            });

            imageFeed.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View view) {

                    if (listener != null) {
                        listener.onFotoSelected(snapshot);

                    }

                }
            });

            comentarios.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View view) {

                    if (listener != null) {
                        listener.onCommentsSelected(snapshot);
                    }

                }
            });

            linear_curtidas.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View view) {


                    if (listener != null) {
                        listener.onCurtidasSelected(snapshot);

                    }
                }
            });

            // Click listener
            itemView.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View view) {
                    if (listener != null) {
                        listener.onPostSelected(snapshot);
                    }
                }
            });

        }


    }


}

Answer 1

要实现此目的，您需要使用嵌套查询两次查询数据库。首先，您需要查询数据库以获取与单个用户对应的所有朋友ID，然后根据这些ID来第二次查询数据库，以仅显示与这些特定朋友对应的帖子。

需要注意的是，这不能在单个查询中完成。

如何查看用户帖子的朋友 - Firestore

1 个答案: