public void addItemToOrder(Context context, final Order order, final Item item) {
    final SQLiteDatabase db = this.getWritableDatabase();
    final Toast errorToast = Toast.makeText(context, "Problema en el servidor", Toast.LENGTH_SHORT);
    final Context mContext = context;
    ApiClient.getRestAppApiClient(context)
        .addItemToOrder(
            order.getId(),
            item.getId(),
            1,
            new Callback<com.tesis.restapp.restapp.database.Response>() {
              @Override
              public void success(
                  com.tesis.restapp.restapp.database.Response data,
                  retrofit.client.Response response) {

                if (data.wasSuccessful()) {
                  ContentValues values = new ContentValues();

                  values.put(KEY_ID, data.getId());
                  values.put(KEY_ORDER_ID, order.getId());
                  values.put(KEY_ITEM_ID, item.getId());
                  values.put(KEY_QUANTITY, 1);
                  values.put(KEY_PRICE, item.getPrice());
                  // Inserting Row
                  db.insert(TABLE_ORDER_ITEM, null, values);

                  itemsInOrderAdapter.notifyDataSetChanged();
                  ordersAdapter.aNotifyDataSetChanged();
                } else {
                  Toast.makeText(mContext, data.getMessage(), Toast.LENGTH_SHORT).show();
                }
                db.close(); // Closing database connection
              }

              @Override
              public void failure(RetrofitError error) {
                errorToast.show();
                Log.e(this.getClass().getSimpleName(), error.getMessage());
                db.close();
              }
            });
  }
  public void removeItemFromOrder(
      Context context, final Order order, final Item item, final ImageButton btn) {
    final SQLiteDatabase db = this.getWritableDatabase();

    final Toast errorToast = Toast.makeText(context, "Problema en el servidor", Toast.LENGTH_SHORT);
    final Context mContext = context;
    String selectQuery =
        "SELECT * FROM "
            + TABLE_ORDER_ITEM
            + " WHERE "
            + TABLE_ORDER_ITEM
            + "."
            + KEY_ITEM_ID
            + "="
            + item.getId()
            + " AND "
            + TABLE_ORDER_ITEM
            + "."
            + KEY_ORDER_ID
            + " ="
            + order.getId();

    Cursor cursor = db.rawQuery(selectQuery, null);

    // looping through all rows and adding to list
    if (cursor.moveToFirst()) {

      ApiClient.getRestAppApiClient(context)
          .removeItemFromOrder(
              cursor.getInt(cursor.getColumnIndex(KEY_ID)),
              new Callback<com.tesis.restapp.restapp.database.Response>() {
                @Override
                public void success(
                    com.tesis.restapp.restapp.database.Response apiResponse, Response response) {
                  if (apiResponse.wasSuccessful()) {
                    db.delete(
                        TABLE_ORDER_ITEM,
                        "id = ?",
                        new String[] {String.valueOf(apiResponse.getId())});
                    order.removeItem(item);
                    itemsInOrderAdapter.notifyDataSetChanged();
                  } else {
                    Toast.makeText(mContext, apiResponse.getMessage(), Toast.LENGTH_SHORT).show();
                    btn.post(
                        new Runnable() {
                          @Override
                          public void run() {
                            btn.setVisibility(View.VISIBLE);
                          }
                        });
                  }
                  db.close(); // Closing database connection
                }

                @Override
                public void failure(RetrofitError error) {
                  errorToast.show();
                  db.close();
                  btn.post(
                      new Runnable() {
                        @Override
                        public void run() {
                          btn.setVisibility(View.VISIBLE);
                        }
                      });
                }
              });
    }
  }