Question

我想在一个名为“ Likes”的节点下检索数据，然后在其中存储“ postID”（也恰好是发布的键）和一个子“ UID”，其中包含我要检索的所有数据。

我尝试遵循本教程，但未成功。 Android Firebase retrieve data from all nodes (nested) in Fragments

databaseReference = FirebaseDatabase.getInstance().getReference().child("Likes");


        mQuery = databaseReference.orderByChild("uid").equalTo(current_user);
 protected void onStart() {
        super.onStart();


        Toast.makeText(this, house+ " "+mAuth.getCurrentUser().getUid(), Toast.LENGTH_LONG).show();
        final String user_id = mAuth.getCurrentUser().getUid();

    FirebaseRecyclerAdapter<FavHelper, FavouriteActivity.FavViewHolder> firebaseRecyclerAdapter = new FirebaseRecyclerAdapter<FavHelper, FavouriteActivity.FavViewHolder>(FavHelper.class, R.layout.favourite_item, FavouriteActivity.FavViewHolder.class, mQuery) {
        @Override
        protected void populateViewHolder(final FavouriteActivity.FavViewHolder viewHolder, FavHelper model, int position) {



                final String house_id = getRef(position).getKey();

                //if (house_id != null) {
                viewHolder.setPrice(model.getPrice());
                viewHolder.setPlace(model.getPlace());
                viewHolder.setLocation(model.getLocation());
                viewHolder.setImage(getApplicationContext(), model.getImage());

                viewHolder.setFavBtn(house_id);




        }

我想显示只有用户喜欢的帖子。find the pic of the database here

Answer 1

我通过更改数据的存储方式（即，而不是将数据存储在

下）解决了该问题

.child(house_id).child(user_id)，我用过.child(user_id).child(house_id)。但是现在我遇到了一个问题，当我尝试保存多个数据时，它将替换现有数据而不是添加数据。 [该应用的屏幕截图][1]我在做什么错了？

我的代码：

 viewHolder.favBtn.setOnClickListener(new View.OnClickListener() {
                    @Override
                    public void onClick(View v) {
                        mProcessLike = true;

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

                                    if (mProcessLike) {
                                        if (mAuth.getCurrentUser() != null) {
                                            String user = mAuth.getCurrentUser().getUid();
                                            if (dataSnapshot.hasChild(user) ) {
                                                mDatabaseLikes.child(user).child(house_id).removeValue();
                                                mProcessLike = false;

                                            } else {


                                                KejaHelper keja = new KejaHelper(getApplicationContext());
                                                TextView loc = findViewById(R.id.txtLocation);
                                                TextView place = findViewById(R.id.txtPlace);
                                                TextView price = findViewById(R.id.txtPrice);
                                                TextView img = findViewById(R.id.txtKey);
                                            //    String imag = keja.getImage().toString();


                                                dataSnapshot.getValue();


                                                HashMap<String, Object> map = new HashMap<>();
                                                map.put("name", loc.getText().toString());
                                                map.put("place", place.getText().toString());
                                                map.put("price",price.getText().toString());
                                                map.put("image",img.getText().toString());
                                                map.put("fav", "love");




                                                mDatabaseLikes.child(user).child(house_id).updateChildren(map);
                                               // Toast.makeText(MainActivity.this, , Toast.LENGTH_SHORT).show();
                                                mProcessLike = false;
                                            }
                                        }
                                    }
                                }
enter code here
enter code here

如何从Firebase中的嵌套节点检索数据

1 个答案: