ArticleListFragment.java

package vit.vithandbook.fragment;


import android.content.Intent;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.os.AsyncTask;
import android.os.Bundle;
import android.support.v7.widget.LinearLayoutManager;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ProgressBar;

import java.util.ArrayList;

import vit.vithandbook.R;
import vit.vithandbook.activity.ArticleActivity;
import vit.vithandbook.adapter.ArticleListAdapter;
import vit.vithandbook.adapter.onItemClickListener;
import vit.vithandbook.helperClass.DataBaseHelper;

public class ArticleListFragment extends BackHandlerFragment{

    ArrayList<String> topics;
    String articleSubCategory;
    ArticleListAdapter rvAdapter;
    ProgressBar load;
    android.support.v7.widget.RecyclerView recyclerView;

    public ArticleListFragment() {
    }
    public static ArticleListFragment newInstance(String SubCategory) {
        ArticleListFragment frag = new ArticleListFragment();
        frag.articleSubCategory = SubCategory;
        return frag;
    }


    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        View view = inflater.inflate(R.layout.fragment_article_list, container, false);
        load = (ProgressBar) view.findViewById(R.id.alprogressbar);
        recyclerView = (android.support.v7.widget.RecyclerView) view.findViewById(R.id.article_rv_list);
        new AsyncTask<Void, Void, Void>() {

            @Override
            protected void onPreExecute() {
                load.setVisibility(View.VISIBLE);
            }

            @Override
            protected Void doInBackground(Void... params) {
                fetchArticleData();
                // sample data remove to test with actual data
                return null;
            }

            @Override
            protected void onPostExecute(Void res) {
                load.setVisibility(View.GONE);
                rvAdapter = new ArticleListAdapter(getActivity(),topics);
                rvAdapter.setOnItemClickListener(new onItemClickListener() {
                    @Override
                    public void onItemClick(String data) {
                        onListItemClick(data);

                    }
                });
                recyclerView.setAdapter(rvAdapter);
                recyclerView.setLayoutManager(new LinearLayoutManager(getActivity()));
            }
        }.execute();
        return view;
    }

    @Override
    public boolean onBackPressed() {

        return false;
    }

    public void onListItemClick(String data) {
        Intent intent = new Intent(getActivity(), ArticleActivity.class);
        intent.putExtra("topic", data);
        startActivity(intent);
    }

    void fetchArticleData() {
        SQLiteDatabase db = null;
        Cursor cursor = null;
        try {
            db = SQLiteDatabase.openDatabase(DataBaseHelper.DB_PATH + DataBaseHelper.DB_NAME, null, SQLiteDatabase.OPEN_READWRITE);
            cursor = db.rawQuery("SELECT distinct `topic` from `articles` Where sub_category = ?", new String[]{articleSubCategory});
            topics = new ArrayList<String>();
            cursor.moveToFirst();
            while (!cursor.isAfterLast()) {
                topics.add(cursor.getString(0));
                cursor.moveToNext();
            }
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            cursor.close();
            db.close();
        }

    }


}