NullPointerException异常将项目添加到列表时 [英] NullPointerException when adding an Item to the list

问题描述

直升机所有，

我有我面临NullPointerException异常问题时，我想将项目添加到列表中，如下图所示：

I have a problem that I am facing NullPointerException when I want to add an item to the List, as shown below:

public List<SearchResponse> sortMPGListViewForNA(List<SearchResponse> response)
    {
        List<SearchResponse> list = response;
        List<SearchResponse> tempMPG = null, tempPrice = null, tempRating = null;
        for(int i=0;i<response.size();i++)
        {
            if(response.get(i).years.get(0).mpg.equalsIgnoreCase("n/a"))
            {
                tempMPG.add(response.get(i));
                list.remove(i);
            }
            if(response.get(i).years.get(0).price.equalsIgnoreCase("n/a"))
            {
                tempPrice.add(response.get(i));
                list.remove(i);
            }
            if(response.get(i).years.get(0).rating.equalsIgnoreCase("n/a"))
            {
                tempRating.add(response.get(i));//NPE Occurs Here
                list.remove(i);
            }
        }
        response.addAll(tempMPG);
        response.addAll(tempPrice);
        response.addAll(tempRating);
        return response;
    }

请给我建议的任何解决方案，就以相同的。

Please suggest me any solution regarding to the same.

在此先感谢。

推荐答案

您需要初始化tempMPG，tempPrice和tempRating：

You need to initialize tempMPG, tempPrice and tempRating:

tempMpg = new ArrayList<SearchResponse>();
tempPrice = new ArrayList<SearchResponse>();
tempRating = new ArrayList<SearchResponse>();

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