How to sort RecyclerView item in android

Question

I'm working on a android chatting application. When I called my api it returns me the chat list sorted by a user_id. But what I need to do is serialized by message_id as I want to show last message first.Here is my onBindViewHolder method in which i get the values.

public void onBindViewHolder(final MyAdapter_HomeViewHolder holder, final int position) {

    holder.userNameTV.setText(data.get(position).getUserInfo().getFullName());
    holder.msgBodyTV.setText(data.get(position).getBody());
    holder.originator_iD.setText(data.get(position).getUserInfo().getId().toString());

    //message ID. I need to serialize my recyclerView by this ID.biggest id should appear first.
    holder.messageId.setText(data.get(position).getId().toString());

    holder.owner_type_ET.setText("1");
    holder.subject_ET.setText("Message");

}

In case of you need to see the full code, https://pastebin.com/Zxmq36Gn

Answer 1

try this before passing your list to the adapter (after API call and before adapter notifydatasetchanged):

 Collections.sort(data, new Comparator<CustomData>() {
            @Override
            public int compare(CustomData lhs, CustomData rhs) {
                // -1 - less than, 1 - greater than, 0 - equal, all inversed for descending
                return lhs.getId() > rhs.getId() ? -1 : (lhs.customInt < rhs.customInt ) ? 1 : 0;
            }
        });

Answer 2

Add this lines of code before passing to RecyclerView Adapter

Collections.sort(yourLists, new Comparator<YourList>() {
        @Override
        public int compare(YourList lhs, YourList rhs) {
            return lhs.getId().compareTo(rhs.getId());
        }
    });

Answer 3

 Collections.sort(response.body(), new Comparator<All_posts>() {
                        @Override
                        public int compare(All_posts lhs, All_posts rhs) {
                            if(lhs.getId() > rhs.getId()) {
                                return -1;
                            } else {
                                return 1;
                            }
                        }
                    });

• "response.body" is the arraylist I got from json, this is what I pass to the recycler view adapter,

• "All_posts" is the "Model" class, the one which contains only fields;

• And getId is the value I want comparison to take place on it, it's from my model class,

I wrote this before I set my adapter to my recycler view. and after I set my adpater to my recyclerView, I wrote recyclerView.getAdapter().notifyDataSetChanged();

Answer 4

in Kotlin use like this after loading data in array:

myItems.sortWith(Comparator { lhs, rhs ->
            // -1 - less than, 1 - greater than, 0 - equal, all inversed for descending
            if (lhs.name > rhs.name) -1 else if (lhs.id < rhs.id) 1 else 0
        })

After that apply:

myItemAdapter.notifyDataSetChanged()

Answer 5

Before passing the data to RecyclerView adapter

data.sort(new Comparator<Datum>() {
            @Override
            public int compare(Datum o1, Datum o2) {
                return o1.get(position).getMessageId().compareTo(o2.get(position).getMessageId());
            }
        });

then pass (notify) the sorted list to the adapter.