如何显示按最喜欢的评论过滤的recyclerview项目？

Posted 2023-02-24

【中文标题】如何显示按最喜欢的评论过滤的recyclerview项目？

【英文标题】：How to show recyclerview items filtered by most-liked comments?

【发布时间】：2019-12-18 00:40:36

【问题描述】：

我想创建一个小型社交应用。我几乎完成了，但我不知道如何在 RecyclerView 中显示评论项，基于最喜欢的那些。

这里是代码

 //This is commentAdapter
 public void onBindViewHolder(@NonNull final Myholder myHolder, final int i) 
    final ModelComments modelComments = commentsList.get(i);
    String cLikes = commentsList.get(i).getcLikes(); //this is for like

myHolder.user_comment.setText(modelComments.getComment());
    myHolder.clickBtn.setText(cLikes);//to show how many likes the user get



//This is commentsActivity
 RecyclerView recyclerView;
FirebaseAuth firebaseAuth;
FirebaseUser user;
private CommentAdapter commentAdapter;
private List<ModelComments> commentsList;

recyclerView = findViewById(R.id.comment_recycler);
LinearLayoutManager layoutManager = new LinearLayoutManager(this);
    //show newest comment first and then old
    layoutManager.setStackFromEnd(true);
    layoutManager.setReverseLayout(true);
    recyclerView.setLayoutManager(layoutManager);
    commentsList = new ArrayList<>();
    commentAdapter= new CommentAdapter(this, commentsList);
    recyclerView.setAdapter(commentAdapter);

showAllComment();


private void showAllComment() 
 try 
        DatabaseReference reference = FirebaseDatabase.getInstance().getReference("comments");
        reference.addValueEventListener(new ValueEventListener() 
            @Override
            public void onDataChange(@NonNull DataSnapshot dataSnapshot) 
                commentsList.clear();
                for (DataSnapshot snapshot : dataSnapshot.getChildren()) 
                    ModelComments modelComments = snapshot.getValue(ModelComments.class);
                    commentsList.add(modelComments);
                

                commentAdapter.notifyDataSetChanged();
            

            @Override
            public void onCancelled(@NonNull DatabaseError databaseError) 

            
        );
     catch (Exception e) 
        e.printStackTrace();
    

再一次，有什么办法可以做到这一点？如果您不明白，请在此问题上发表评论。

【问题讨论】：

排序列表然后绑定到适配器

但是怎么绑定呢？

【参考方案1】：

如我们所见，您已经通过以下操作完成了绑定

commentsList.clear();
for (DataSnapshot snapshot : dataSnapshot.getChildren()) 
    ModelComments modelComments = snapshot.getValue(ModelComments.class);
    commentsList.add(modelComments);

commentAdapter.notifyDataSetChanged();

首先，您清除了列表，然后添加了 cmets，最后调用了 notifyDataSetChanged。您错过的是在通知数据更改之前对列表进行排序

请查看此链接以了解如何对列表进行排序。 Sort ArrayList of custom Objects by property