ContentProvider#query

EventProvider.java

  @Override
  public Cursor query(Uri uri, String[] projection, String selection, String[] selectionArgs, String sortOrder) {
    SQLiteDatabase db = dbHelper.getReadableDatabase();
    if(sURIMatcher.match(uri) == EVENTS) {
      String selectClauses = "";
      for(int i=0; i < projection.length; i++) {
        if(projection[i] == "participants_count") {
           selectClauses += "(SELECT COUNT(*) FROM participants WHERE participants.event_id = events.event_id)";
        } else {
           selectClauses += projection[i];
        }
      }
      // Handle the where clauses
      String whereClauses = "";
      Cursor c = db.rawQuery("SELECT " + selectClauses
        + " FROM events"
        + " WHERE " + whereClauses;
       return c;
    } else {
    SQLiteQueryBuilder qBuilder = new SQLiteQueryBuilder();
    switch (sURIMatcher.match(uri)) {
      case EVENTS:
        qBuilder.setTables(Tables.EVENTS);
        break;
      case LOCATIONS:
        qBuilder.setTables(Tables.LOCATIONS);
        break;
      case TIMESLOTS:
        qBuilder.setTables(Tables.TIMESLOTS);
        break;
      case PARTICIPANTS:
        qBuilder.setTables(Tables.PARTICIPANTS);
        break;
      case EVENTS_ID:
        qBuilder.setTables(Tables.EVENTS);
        qBuilder.appendWhere("_ID=" + uri.getLastPathSegment());
        break;
      case LOCATIONS_ID:
        qBuilder.setTables(Tables.LOCATIONS);
        qBuilder.appendWhere("_ID=" + uri.getLastPathSegment());
        break;
      case TIMESLOTS_ID:
        qBuilder.setTables(Tables.TIMESLOTS);
        qBuilder.appendWhere("_ID=" + uri.getLastPathSegment());
        break;
      case PARTICIPANTS_ID:
        qBuilder.setTables(Tables.PARTICIPANTS);
        qBuilder.appendWhere("_ID=" + uri.getLastPathSegment());
        break;
      default:
        throw new IllegalArgumentException("Unknown URI " + uri);
    }


    Cursor c = qBuilder.query(db,
            projection,
            selection,
            selectionArgs,
            null,
            null,
            sortOrder);
    c.setNotificationUri(getContext().getContentResolver(), uri);
    return c;
    }
  }