Question

我的数据库：

我想从firebase数据库中检索用户ID。我怎么能这样做？

我的代码是：

///////////// Recycler Firebase /////////////

firebaseRecyclerAdapter = new FirebaseRecyclerAdapter<Post, PostViewHolder>(
        Post.class,
        R.layout.post_row,
        PostViewHolder.class,
        dbpostShow
) {

    @Override
    protected void populateViewHolder(final PostViewHolder viewHolder, Post model, int position) {

        String listPostKey = getRef(position).getKey();



        viewHolder.setTextPost(model.getText_post());
        viewHolder.setHospitalName(model.getHospital_name());
        viewHolder.setFullNameUserPoster(model.getPoster_name());
        viewHolder.setAgeUserPoster(model.getPoster_age());

        String lastSeenAgo = GetTimeAgo.getTimeAgo(model.getTime_post_ago(), getContext());
        viewHolder.setTimePostAgo(lastSeenAgo);

        viewHolder.setTypeBloodneedPoster(model.getPoster_type_blood());
        Toast.makeText(getActivity(), model.getPoster_type_blood(), Toast.LENGTH_SHORT).show();

    }
};


recyclerView.setAdapter(firebaseRecyclerAdapter);

Answer 1

如果您已在userId类中创建变量Post并使用getter获取值。

否则，您可以使用addListenerForSingleValueEvent获取值：

以下是如何使用它的示例。

firebaseRecyclerAdapter = new FirebaseRecyclerAdapter<Post, PostViewHolder>(
                Post.class,
                R.layout.post_row,
                PostViewHolder.class,
                dbpostShow
        ) {

            @Override
            protected void populateViewHolder(final PostViewHolder viewHolder, Post model, int position) {

                String listPostKey = getRef(position).getKey();



                DatabaseReference ref = FirebaseDatabase.getInstance().getReference().child("Post").child("country").child("city").child(listPostKey).child("userId");

                        ref.addListenerForSingleValueEvent(new ValueEventListener() {
                            @Override
                            public void onDataChange(DataSnapshot dataSnapshot) {

                                String userID = String.valueOf(dataSnapshot.getValue());

                            }

                            @Override
                            public void onCancelled(DatabaseError databaseError) {

                            }
                        });
            }
        };
        recyclerView.setAdapter(firebaseRecyclerAdapter);

Answer 2

在下面的代码中添加了您的用户ID时，您无法跟踪价值，并确保您的父级位置正确

yourRef.addChildEventListener(new ChildEventListener() {
                            @Override
                            public void onChildAdded(DataSnapshot dataSnapshot, String s) {

                            }

                            @Override
                            public void onChildChanged(DataSnapshot dataSnapshot, String s) {

                            }

                            @Override
                            public void onChildRemoved(DataSnapshot dataSnapshot) {

                            }

                            @Override
                            public void onChildMoved(DataSnapshot dataSnapshot, String s) {

                            }

                            @Override
                            public void onCancelled(DatabaseError databaseError) {

                            }
                        })

如何在firebaseRecyclerAdapter上获取用户标识的值

2 个答案: