Android Open Source - tum-campus News Manager

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License

The source code is released under:

GNU General Public License

Java Source Code

?package de.tum.in.tumcampus.models;
/*w w w. jav a 2 s . c  om*/
import java.net.URLEncoder;
import java.util.Arrays;
import java.util.Date;

import org.json.JSONArray;
import org.json.JSONObject;

import de.tum.in.tumcampus.common.Utils;

import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;

/**
 * News Manager, handles database stuff, external imports
 */
public class NewsManager {

  /**
   * Database connection
   */
  private SQLiteDatabase db;

  /**
   * Last insert counter
   */
  public static int lastInserted = 0;

  /**
   * Constructor, open/create database, create table if necessary
   * 
   * <pre>
   * @param context Context
   * </pre>
   */
  public NewsManager(Context context) {
    db = DatabaseManager.getDb(context);

    // create table if needed
    db.execSQL("CREATE TABLE IF NOT EXISTS news (id VARCHAR PRIMARY KEY, message VARCHAR, link VARCHAR, "
        + "image VARCHAR, date VARCHAR)");
  }

  /**
   * Download news from external interface (JSON)
   * 
   * <pre>
   * @param force True to force download over normal sync period, else false
   * @throws Exception
   * </pre>
   */
  public void downloadFromExternal(boolean force) throws Exception {

    if (!force && !SyncManager.needSync(db, this, 86400)) {
      return;
    }

    String url = "https://graph.facebook.com/162327853831856/feed/?limit=100&access_token=";
    String token = "141869875879732|FbjTXY-wtr06A18W9wfhU8GCkwU";

    JSONArray jsonArray = Utils.downloadJson(url + URLEncoder.encode(token)).getJSONArray("data");

    cleanupDb();
    int count = Utils.dbGetTableCount(db, "news");

    db.beginTransaction();
    try {
      int countItems = 0;
      for (int i = 0; i < jsonArray.length(); i++) {
        JSONObject obj = jsonArray.getJSONObject(i);

        String[] types = new String[] { "photo", "link", "video" };
        String[] ids = new String[] { "162327853831856_228060957258545", "162327853831856_228060957258545",
            "162327853831856_224344127630228" };

        // filter out events, empty items
        if ((!Arrays.asList(types).contains(obj.getString("type")) && !Arrays.asList(ids).contains(
            obj.getString("id")))
            || !obj.getJSONObject("from").getString("id").equals("162327853831856")) {
          continue;
        }
        if (obj.has("name") && obj.getString("name").equals("Kurz notiert")) {
          continue;
        }
        if (countItems > 24) {
          break;
        }
        replaceIntoDb(getFromJson(obj));
        countItems++;
      }
      SyncManager.replaceIntoDb(db, this);
      db.setTransactionSuccessful();
    } finally {
      db.endTransaction();
    }
    // update last insert counter
    lastInserted += Utils.dbGetTableCount(db, "news") - count;
  }

  /**
   * Get all news from the database
   * 
   * @return Database cursor (image, message, date_de, link, _id)
   */
  public Cursor getAllFromDb() {
    return db.rawQuery("SELECT image, message, strftime('%d.%m.%Y', date) as date_de, link, id as _id "
        + "FROM news ORDER BY date DESC", null);
  }

  /**
   * Convert JSON object to News and download news image
   * 
   * Example JSON: e.g. { "id": "162327853831856_174943842570257", "from": { ... }, "message": "Testing ...", "picture":
   * "http://photos-d.ak.fbcdn.net/hphotos-ak-ash4/268937_174943835903591_162327853831856_476156_7175901_s.jpg" , "link":
   * "https://www.facebook.com/photo.php?fbid=174943835903591&set=a.174943832570258.47966.162327853831856&type=1" , "name": "Wall Photos", "icon":
   * "http://static.ak.fbcdn.net/rsrc.php/v1/yz/r/StEh3RhPvjk.gif", "type": "photo", "object_id": "174943835903591", "created_time":
   * "2011-07-04T01:58:25+0000", "updated_time": "2011-07-04T01:58:25+0000" },
   * 
   * <pre>
   * @param json see above
   * @return News
   * @throws Exception
   * </pre>
   */
  public static News getFromJson(JSONObject json) throws Exception {

    String target = "";
    if (json.has("picture")) {
      String picture = json.getString("picture");
      target = Utils.getCacheDir("news/cache") + Utils.md5(picture) + ".jpg";
      Utils.downloadFileThread(picture, target);
    }
    String link = "";
    if (json.has("link") && !json.getString("link").contains("www.facebook.com")) {
      link = json.getString("link");
    }
    if (link.length() == 0 && json.has("object_id")) {
      link = "http://graph.facebook.com/" + json.getString("object_id") + "/Picture?type=normal";
    }

    // message empty => description empty => caption
    String message = "";
    if (json.has("message")) {
      message = json.getString("message");
    } else if (json.has("description")) {
      message = json.getString("description");
    } else if (json.has("caption")) {
      message = json.getString("caption");
    } else if (json.has("name")) {
      message = json.getString("name");
    }
    Date date = Utils.getDate(json.getString("created_time"));

    return new News(json.getString("id"), message, link, target, date);
  }

  /**
   * Replace or Insert a event in the database
   * 
   * <pre>
   * @param n News object
   * @throws Exception
   * </pre>
   */
  public void replaceIntoDb(News n) throws Exception {
    Utils.log(n.toString());

    if (n.id.length() == 0) {
      throw new Exception("Invalid id.");
    }
    if (n.message.length() == 0) {
      throw new Exception("Invalid message.");
    }
    db.execSQL("REPLACE INTO news (id, message, link, image, date) VALUES (?, ?, ?, ?, ?)", new String[] { n.id,
        n.message, n.link, n.image, Utils.getDateString(n.date) });
  }

  /**
   * Removes all cache items
   */
  public void removeCache() {
    db.execSQL("DELETE FROM news");
    Utils.emptyCacheDir("news/cache");
  }

  /**
   * Removes all old items (older than 3 months)
   */
  public void cleanupDb() {
    db.execSQL("DELETE FROM news WHERE date < date('now','-3 month')");
  }
}

Java Source Code List

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