Android Open Source - tum-campus Event 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;
//from www  .j  a  v a 2 s . c om
import java.net.URLEncoder;

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;

/**
 * Event Manager, handles database stuff, external imports
 */
public class EventManager {

  /**
   * 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 EventManager(Context context) {
    db = DatabaseManager.getDb(context);

    // create table if needed
    db.execSQL("CREATE TABLE IF NOT EXISTS events (id VARCHAR PRIMARY KEY, name VARCHAR, start VARCHAR, "
        + "end VARCHAR, location VARCHAR, description VARCHAR, link VARCHAR, image VARCHAR)");
  }

  /**
   * Download events 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, 21600)) { // 6h
      return;
    }

    String url = "https://graph.facebook.com/162327853831856/events?"
        + "fields=id,name,start_time,end_time,location,description&limit=50&access_token=";
    String token = "141869875879732|FbjTXY-wtr06A18W9wfhU8GCkwU";

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

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

    db.beginTransaction();
    try {
      for (int i = 0; i < jsonArray.length(); i++) {
        replaceIntoDb(getFromJson(jsonArray.getJSONObject(i)));
      }
      SyncManager.replaceIntoDb(db, this);
      db.setTransactionSuccessful();
    } finally {
      db.endTransaction();
    }
    // update last insert counter
    lastInserted += Utils.dbGetTableCount(db, "events") - count;
  }

  /**
   * Get all upcoming or unfinished events from the database
   * 
   * @return Database cursor (image, name, weekday, start_de, end_de, location, _id)
   */
  public Cursor getNextFromDb() {
    return db.rawQuery("SELECT image, name, strftime('%w', start) as weekday, "
        + "strftime('%d.%m.%Y %H:%M', start) as start_de, strftime('%H:%M', end) as end_de, "
        + "location, id as _id FROM events WHERE end > datetime('now', 'localtime') "
        + "ORDER BY start ASC LIMIT 25", null);
  }

  /**
   * Get all finished events from the database
   * 
   * @return Database cursor (image, name, weekday, start_de, end_de, location, _id)
   */
  public Cursor getPastFromDb() {
    return db.rawQuery("SELECT image, name, strftime('%w', start) as weekday, "
        + "strftime('%d.%m.%Y %H:%M', start) as start_de, strftime('%H:%M', end) as end_de, "
        + "location, id as _id FROM events WHERE end <= datetime('now', 'localtime') "
        + "ORDER BY start DESC LIMIT 50", null);
  }

  /**
   * Get event details form the database
   * 
   * <pre>
   * @param id Event-ID
   * @return Database cursor (image, name, weekday, start_de, end_de, location, description, link, _id)
   * </pre>
   */
  public Cursor getDetailsFromDb(String id) {
    return db.rawQuery("SELECT image, name, strftime('%w', start) as weekday, "
        + "strftime('%d.%m.%Y %H:%M', start) as start_de, strftime('%H:%M', end) as end_de, "
        + "location, description, link, id as _id FROM events WHERE id = ?", new String[] { id });
  }

  /**
   * Convert JSON object to Event, download event picture
   * 
   * Example JSON: e.g. { "id": "166478443419659", "owner": { "name": "TUM Campus App for Android", "category": "Software", "id": "162327853831856" }, "name":
   * "R\u00fcckmeldung f\u00fcr Wintersemester 2011/12", "description": "..." , "start_time": "2011-08-15T00:00:00", "end_time": "2011-08-15T03:00:00",
   * "location": "TU M\u00fcnchen", "privacy": "OPEN", "updated_time": "2011-06-25T06:26:14+0000" }
   * 
   * <pre>
   * @param json see above
   * @return Event
   * @throws Exception
   * </pre>
   */
  public static Event getFromJson(JSONObject json) throws Exception {

    String eventId = json.getString("id");

    String picture = "http://graph.facebook.com/" + eventId + "/Picture?type=large";

    String target = Utils.getCacheDir("events/cache") + eventId + ".jpg";
    Utils.downloadFileThread(picture, target);

    String description = "";
    if (json.has("description")) {
      description = json.getString("description");
    }
    String location = "";
    if (json.has("location")) {
      location = json.getString("location");
    }
    // Link only available in event/feed
    String link = "";

    return new Event(eventId, json.getString("name"), Utils.getDateTime(json.getString("start_time")),
        Utils.getDateTime(json.getString("end_time")), location, description, link, target);
  }

  /**
   * Replace or Insert a event in the database
   * 
   * <pre>
   * @param e Event object
   * @throws Exception
   * </pre>
   */
  public void replaceIntoDb(Event e) throws Exception {
    if (e.id.length() == 0) {
      throw new Exception("Invalid id.");
    }
    if (e.name.length() == 0) {
      throw new Exception("Invalid name.");
    }
    db.execSQL("REPLACE INTO events (id, name, start, end, location, description, link, image) "
        + "VALUES (?, ?, ?, ?, ?, ?, ?, ?)", new String[] { e.id, e.name, Utils.getDateTimeString(e.start),
        Utils.getDateTimeString(e.end), e.location, e.description, e.link, e.image });
  }

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

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

Java Source Code List

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