Firebase：如何获取父节点的父节点？

Question

我有节点，我正在尝试使节点成为父节点。

我正在尝试获取黑线数据。

MAX(id)

这行代码Query query = FirebaseDatabase.getInstance().getReference(Params.GENRESCOMMENTS).child(video.getGenre()) .child(video.getVideoID()); Log.d(TAG,"Query: " + query.toString()); options = new FirebaseRecyclerOptions.Builder<Comment>().setQuery(query,Comment.class).build(); adapter = new FirebaseRecyclerAdapter<Comment,CommentsSingleVideoView>(options) { @Override public CommentsSingleVideoView onCreateViewHolder(ViewGroup parent, int viewType) { View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.comment_item,parent,false); return new CommentsSingleVideoView(view); } @Override protected void onBindViewHolder(CommentsSingleVideoView holder, int position, final Comment model) { Log.d(TAG,"Model: " + model.toString()); final String videoID = (String) this.getSnapshots().getSnapshot(position).getKey(); Log.d(TAG,"Video ID: " + videoID); final String userCommentUID = model.getUserCommentUID(); holder.tvUserName.setText(model.getUserName()); holder.tvComment.setText(model.getComment()); holder.tvDate.setText(model.getUploadDate()); 仅使我得到红线。 我需要获取黑线数据。 我该怎么办？

Answer 1

要获取父节点，请在onBindViewHolder内尝试以下操作：

 String videoID = this.getRef(position).getKey();

---

getRef(position)将返回引用的源位置，而getKey()将检索该节点。

firebaseui文档中的代码：

@NonNull
@Override
public DatabaseReference  getRef(int position) {
    return mSnapshots.getSnapshot(position).getRef();
}

https://github.com/firebase/FirebaseUI-Android/blob/master/database/src/main/java/com/firebase/ui/database/FirebaseRecyclerAdapter.java#L113