Max Billionaire Max Billionaire - 23 days ago 4
Android Question

How to show recently added items first in recyclerview

I'm creating an app similar to the instagram app but only admin can add contents. i used python django for my backend but when i add new item to my django database, it comes last on the recyclerview. I want it to be in a way that, when i add new item, it comes first when you open my app like the way instagram shows recent items first.
This is my custom Adapter class

public class DealAdapter extends RecyclerView.Adapter<DealAdapter.DealHolder> {

Context context;
ArrayList<Deal> arrayList;


public DealAdapter(Context context, ArrayList<Deal> arrayList) {
this.context = context;
this.arrayList = arrayList;
}

@Override
public DealHolder onCreateViewHolder(ViewGroup parent, int viewType) {
LayoutInflater inflater = LayoutInflater.from(context);
View v = inflater.inflate(R.layout.deal_cardview, parent, false);
DealHolder dealHolder = new DealHolder(v);
return dealHolder;
}

@Override
public void onBindViewHolder(DealHolder holder, int position) {
Deal deal = arrayList.get(position);
holder.title.setText(deal.getTitle());
Picasso.with(context).
load(deal.getImage()).
placeholder(R.drawable.loading).
error(android.R.drawable.stat_notify_error).
into(holder.image);

}

@Override
public int getItemCount() {
if(arrayList != null) {
return arrayList.size();
}else {
return 0;
}
}


public class DealHolder extends RecyclerView.ViewHolder {
TextView title;
ImageView image;

public DealHolder(View itemView) {
super(itemView);
title = (TextView) itemView.findViewById(R.id.tvTitle);
image = (ImageView) itemView.findViewById(R.id.ivImage);
}
}
}


This is my main Activity class

public class MainActivity extends AppCompatActivity {
RecyclerView recyclerView;
String TAG = "MainActivity";
ImageButton ibMore;



@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);

recyclerView = (RecyclerView) findViewById(R.id.rvRecyclerview);
LinearLayoutManager layoutManager = new LinearLayoutManager(this);
recyclerView.setLayoutManager(layoutManager);

String url = "http://192.168.43.2/api/deals/?format=json";
StringRequest stringRequest = new StringRequest(Request.Method.GET, url,
new Response.Listener<String>() {
@Override
public void onResponse(String response) {
ArrayList<Deal> userList = new JsonConverter<Deal>().
toArrayList(response, Deal.class);
DealAdapter adapter = new DealAdapter(getApplicationContext(), userList);
recyclerView.setAdapter(adapter);

}
},
new Response.ErrorListener() {
@Override
public void onErrorResponse(VolleyError error) {
Log.d(TAG, error.toString());
Toast.makeText(getApplicationContext(), "Something Went wrong: " + "'" + error + "'", Toast.LENGTH_LONG).show();

}
});

MySingleton.getInstance(getApplicationContext()).addToRequestQueue(stringRequest);

}
}

Answer

Okay so this is what worked for me. After getting JSON and converting to ArrayList, i called it in "Collections.reverse(arrayList);" before adding it to the adapter as shown below.

new Response.Listener<String>() {
            @Override
            public void onResponse(String response) {
                ArrayList<Deal> userList = new JsonConverter<Deal>().
                        toArrayList(response, Deal.class);

                Collections.reverse(userList);

                DealAdapter adapter = new DealAdapter(getApplicationContext(), userList);
                recyclerView.setAdapter(adapter);

            }
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