Android Open Source - RSSNewsReaderApp Helper

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License

The source code is released under:
GNU General Public License
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Java Source Code

package com.romanostrechlis.rssnews.auxiliary;
/*www  .j a  v a 2s.co m*/
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.CopyOnWriteArrayList;
import java.util.concurrent.ExecutionException;

import org.json.JSONException;
import org.json.JSONObject;

import android.app.Activity;
import android.content.Context;
import android.content.SharedPreferences;
import android.content.SharedPreferences.Editor;
import android.content.res.AssetManager;
import android.net.ConnectivityManager;
import android.net.NetworkInfo;
import android.util.Log;
import android.widget.Toast;

import com.romanostrechlis.rssnews.content.RssFeed;
import com.romanostrechlis.rssnews.content.RssItem;

/**
 * Provides static methods for the application
 * 
 * <p><h3>Methods Implemented</h3>
 * <ul>
 * <li>{@link #addItemFeed(RssFeed)}: add a new RssFeed to the database.</li>
 * <li>{@link #createDB(DatabaseHandler, AssetManager, Context)}: populates database based on the json elements inside assets folder.</li>
 * <li>{@link #readRSSAll(DatabaseHandler)}: gets a list with all RssFeed objects in database.</li>
 * <li>{@link $makeUpdateList(List): populates the {@link #ITEMS} List for update purposes.</li>
 * <li>{@link #downloadContent(DatabaseHandler)}: downloads the content from the web and parse it into RssItem objects.</li>
 * <li>{@link #isConnected(Activity)}: checks whether application has Internet connection.</li>
 * <li>{@link #getUpdateInterval(Context)}: retrieves the number of milliseconds that the UpdateService sleeps.</li>
 * <li>{@link #setUpdateInterval(Context, int)}: sets the new interval that the UpdateService should sleep.</li>
 * </ul>
 * 
 * @author Romanos Trechlis
 */
public class Helper {

  public static List<RssFeed> ITEMS = new CopyOnWriteArrayList<RssFeed>(); //new ArrayList<RssFeed>();
  public static Map<String, RssFeed> ITEM_MAP = new ConcurrentHashMap<String, RssFeed>(); //new HashMap<String, RssFeed>();

  public static List<RssFeed> ITEMS_TOTAL = new ArrayList<RssFeed>();
  public static Map<String, RssFeed> ITEM_MAP_TOTAL = new HashMap<String, RssFeed>();

  /** variable sets the sleep time in ms */
  public static String PREFERENCES = "AppPreferences";
  private static SharedPreferences sharedPreferences;
  private static int DEF_INTERVAL = 60000; // 1min
  
  /**
   * Retrieves the number of milliseconds that the UpdateService sleeps.
   * 
   * @param context
   * @return number of milliseconds to sleep before the next update
   */
  public static int getUpdateInterval(Context context) {
    sharedPreferences = context.getSharedPreferences(PREFERENCES, Context.MODE_PRIVATE);
    int interval = sharedPreferences.getInt("UpdateInterval", DEF_INTERVAL);
    // Log.d(TAG, "New Interval: " + interval);
    return interval;
  }
  
  /**
   * Sets the new interval that the UpdateService should sleep.
   * 
   * @param context
   * @param newInterval
   */
  public static void setUpdateInterval(Context context, int newInterval) {
    sharedPreferences = context.getSharedPreferences(PREFERENCES, Context.MODE_PRIVATE);
    Editor editor = sharedPreferences.edit();
    editor.putInt("UpdateInterval", newInterval);
    editor.commit();
    // Log.d(TAG, "New Interval: " + getUpdateInterval(context));
  }
  
  private static final String TAG = "Content";

  private static int savedGroupPosition;
  public static void setSavedGroupPosition(int groupPosition) { savedGroupPosition = groupPosition; }
  public static int getSavedGroupPostion() { return savedGroupPosition; }
  
  /** Auto-generated code. */
  private static void addItem(RssFeed item) {
    Helper.ITEMS.add(item);
    Helper.ITEM_MAP.put(item.getId(), item);
  }

  /**
   * Gets all RssFeed objects from database and populates ITEMS_TOTAL and ITEM_MAP_TOTAL.
   * 
   * <p>Used by ManageActivity.
   * 
   * @param db
   */
  public static void readRSSAll(DatabaseHandler db) {
    Helper.ITEMS_TOTAL.clear();
    Helper.ITEM_MAP_TOTAL.clear();

    // Taking ALL RssFeed from the database and append them to Content.ITEMS_TOTAL
    // Log.d(LOGCAT, "Getting All RssFeed from db!!!");
    List<RssFeed> list = db.getAllRssFeed();
    // Log.d(LOGCAT, String.valueOf(list.size()));
    for (RssFeed mFeed : list) {
      // Log.d(LOGCAT, "mFeed.getEnabled(): " + String.valueOf(mFeed.getEnabled()));
      Helper.ITEMS_TOTAL.add(mFeed);
      Helper.ITEM_MAP_TOTAL.put(mFeed.getId(), mFeed);
    }
    // Log.d(LOGCAT, "ITEMS_TOTAL size: " + String.valueOf(Helper.ITEMS_TOTAL.size()));
  }

  /**
   * Populates database based on the json elements inside assets folder
   * 
   * @param db
   * @param assetManager
   * @param context
   */
  public static void createDB(DatabaseHandler db, AssetManager assetManager, Context context) {
    JSONObject json;
    RssFeed feed;
    BufferedReader br;
    Helper.ITEMS.clear();
    Helper.ITEM_MAP.clear();

    /** This code should only run the first time. */
    InputStream is;
    String line;
    if (db.getAllRssFeed().size() == 0) {
      // Log.d(LOGCAT, "This clause is not executed because db.getAllRssFeed().size() = " + db.getAllRssFeed().size());
      try {
        is = assetManager.open("rssfeeds.txt");
        br = new BufferedReader(new InputStreamReader(is));
        while ((line = br.readLine()) != null) {
          json = new JSONObject(line);
          feed = new RssFeed(json.get("id").toString(), 
              json.get("name").toString(), 
              json.get("url").toString(),
              json.get("category").toString());
          feed.setContent("");
          feed.setEnabled(true);
          feed.setNewContent(false);
          feed.setHashCode(0);
          // Log.d(LOGCAT, json.toString());
          db.addRssFeed(feed);
        }
        br.close();
        is.close();
      } catch (IOException | JSONException e) {
        Toast.makeText(context, "Error opening rssfeeds.txt", Toast.LENGTH_LONG).show();
      }
    }
  }

  /**
   * Populates the {@link #ITEMS} List for update purposes.
   * 
   * @param list
   */
  public static void makeUpdateList(List<RssFeed> list) {
    // Taking the enabled RssFeed from the database and append them to Content.ITEMS
    for (RssFeed mFeed : list) {
      addItem(mFeed);
    }
    // Log.d(LOGCAT, String.valueOf(Helper.ITEMS.size()));
  }

  /**
   * Adds an RssItem to database.
   * 
   * @param item  rss feed item with the relevant information.
   * @return true  if successfully adds the rss feed.
   */
  public static Boolean addItemFeed(DatabaseHandler db, RssFeed mFeed) {
    mFeed.setEnabled(true);
    addItem(mFeed);
    return db.addRssFeed(mFeed);
  } 

  /**
   * Checks whether application has Internet connection.
   */
  public static boolean isConnected(Activity a){
    ConnectivityManager connMgr = (ConnectivityManager) a.getSystemService(Activity.CONNECTIVITY_SERVICE);
    NetworkInfo networkInfo = connMgr.getActiveNetworkInfo();
    if (networkInfo != null && networkInfo.isConnected()) 
      return true;
    else
      return false;    
  }

  /**
   * Update individual RssFeed.
   * 
   * @param db
   * @return true   if update was successful
   */
  public static Boolean downloadFeedContent(RssFeed mFeed, DatabaseHandler db, Context context) {
    String data = null;
    // Log.d(LOGCAT, "We 've got so far!!!");
    RetrieveFeedTask rft = new RetrieveFeedTask();
    rft.execute(mFeed.getUrl());
    try {
      data = rft.get();
      mFeed.setContent(data);
      db.updateRssFeed(mFeed);
      mFeed.parseXML();
      for (RssItem ri : mFeed.getList()) {
        db.addRssItem(ri);
      }
      return true;
    } catch (InterruptedException | ExecutionException e) {
      Toast.makeText(context, "Error" + e, Toast.LENGTH_LONG).show();
      return false;
    } 
  }

  /** 
   * Downloads, parse and inserts content and RssItem objects to database
   * 
   * <p> Calls {@link #feedContent(RssFeed, DatabaseHandler)}.
   * @param db
   */
  public static void downloadContent(DatabaseHandler db, Context context) {
    db.dropRssItemTable();
    for (RssFeed mFeed : ITEMS) {
      Helper.downloadFeedContent(mFeed, db, context);
    }
  }
  
  /**
   * Called only by NewFeedsActivity.
   * 
   * @param db
   * @return true   if update was successful
   */
  public static Boolean checkDownloadFeedContent(RssFeed mFeed, DatabaseHandler db, Context context) {
    String data = null;
    // Log.d(LOGCAT, "We 've got so far!!!");
    RetrieveFeedTask rft = new RetrieveFeedTask();
    rft.execute(mFeed.getUrl());
    try {
      data = rft.get();
      if (data != null)
        return true;
      else 
        return false;
    } catch (InterruptedException | ExecutionException e) {
      Toast.makeText(context, "Error" + e, Toast.LENGTH_LONG).show();
      return false;
    } 
  }
}
Java Source Code List
