Question

当json响应值为空时，我得到以上错误

{
"restaurant_area_min_order":null,
"restaurant_id":null
}.

上面的错误出现在try catch块中。当restaurant_area_min_order和restaurant_id中有值时，该函数正常工作且没有错误。如何检查响应数据是否为空并继续执行该函数而没有任何错误？

这是我的代码。

private void getAreaMinOrders()
{
    for(int i = 0; i < Utils.cart_restaurants.size(); i++)
    {
        RestaurantModel restaurant = Utils.cart_restaurants.get(i);
        String restaurant_id = restaurant.getId();

        String url = LinksConstants.BASE_URL + LinksConstants.CHECK_MINIMUM_ORDER;

        RequestParams params = new RequestParams();
        params.put("restaurant_id", restaurant_id);
        params.put("area_id", city_id);

        NetworkRestClient.post(url, params, new JsonHttpResponseHandler()
        {
            @Override
            public void onStart()
            {
                super.onStart();
                progressActivity.showLoading();
            }

            @Override
            public void onSuccess(int statusCode, Header[] headers, JSONObject response)
            {
                super.onSuccess(statusCode, headers, response);
                try
                {
                    if (response != null)
                    {
                        String restaurant_id = response.getString("restaurant_id");

                        String rest_area_min_order = null;

                        if(rest_area_min_order != null)
                        {
                            rest_area_min_order = response.getString("restaurant_area_min_order");
                        }
                        HashMap<String, Object> items_hash = (HashMap<String, Object>) rest_cart_hash.get(restaurant_id);
                        items_hash.put("rest_area_min_order", rest_area_min_order);
                    }
                    progressActivity.showContent();
                }
                catch (Exception ex)
                {
                    GSLogger.e(ex);
                    showError();
                }
            }


            @Override
            public void onFailure(int statusCode, Header[] headers, String errorResponse, Throwable throwable)
            {
                super.onFailure(statusCode, headers, errorResponse, throwable);
                showError();
                if (AppConstants.DEBUG_MODE)
                    showToast(errorResponse);
            }


        }); //end of NetworkRestClient.post
    } //end of for
}

Answer 1

您可以使用JSONObject.isNull()方法检查是否为空。

response.isNull("your_key"); // returns true if the value of that key is null

但是根据您发布的详细信息，您的代码中的HashMap<String, Object> items_hash似乎为空。

添加空检查：

if(restaurant_id != null) {
      HashMap<String, Object> items_hash = (HashMap<String, Object>) rest_cart_hash.get(restaurant_id);
      items_hash.put("rest_area_min_order", rest_area_min_order);
}

尝试调用虚方法＆＃39; java.lang.Object java.util.HashMap.put（java.lang.Object，java.lang.Object）＆＃39;在null对象引用上

1 个答案: