null指针异常解析json与gson android

时间:2012-03-14 10:22:36

标签: android json gson

您好我正在尝试使用gson库解析Json.My Json String就是这个

{
"data": [
    {
        "atb_atestwebservice_cities": [
            {
                "id": "3",
                "cities": "Ajmer",
                "date": "2012-03-01 19:30:32"
            }
        ]
    },
    {
        "atb_atestwebservice_states": [
            {
                "id": "2",
                "states": "goa",
                "date": "2012-02-28 12:53:51"
            }
        ]
    }
]

} 以下课程

public class Cities {

@SerializedName("id")
private String id;

@SerializedName("cities")
private String cities;

@SerializedName("date")
private String date;

public Cities(String id,String city,String date)
{
    this.id=id;
    this.date=date;
    this.cities=city;

}
public String getId()
{
    return id;
}
public String getCity()
{
    return cities;
}
public String getDate()
{
    return date;
}

}  和

public class States {
@SerializedName("id")
private String id;

@SerializedName("states")
private String states;

@SerializedName("date")
private String date;

 public States(String id,String states,String date)
{
    this.id=id;
    this.date=date;
    this.states=states;

}
public String getId()
{
    return id;
}
public String getCity()
{
    return states;
}
public String getDate()
{
    return date;
}

}

和数据类

public class Data {



 private List<Cities> atb_atestwebservice_cities;

 private List<States> atb_atestwebservice_states;

 public Data(List<Cities> cityList,List<States>stateList)
 {
     this.atb_atestwebservice_cities=cityList;
     this.atb_atestwebservice_states=stateList;
 }


 public List<Cities> getCityList()
 {
     return atb_atestwebservice_cities;
 }

 public void setCityList(List<Cities> cityList)
 {
     this.atb_atestwebservice_cities=cityList;
 }

 public List<States> getSateList()
 {
     return atb_atestwebservice_states;
 }

 public void setDatList(List<States> stateList)
 {
     this.atb_atestwebservice_states=stateList;
 }

}  和反序列化json字符串的代码

Gson gson = new Gson();
Data data = gson.fromJson(jsonString,Data.class);

问题是我得到空指针exception.i已经引用了这个link进行解析。我不确定是什么问题。我的POJO类是正确的还是我需要修改或添加更多类? 编辑:这是我的原木猫

  03-14 14:59:31.694: ERROR/AndroidRuntime(323): java.lang.NullPointerException
03-14 14:59:31.694: ERROR/AndroidRuntime(323):     at com.jimesh.ShowData$LongOperation.onPostExecute(ShowData.java:88)
03-14 14:59:31.694: ERROR/AndroidRuntime(323):     at com.jimesh.ShowData$LongOperation.onPostExecute(ShowData.java:1)
03-14 14:59:31.694: ERROR/AndroidRuntime(323):     at android.os.AsyncTask.finish(AsyncTask.java:417)
03-14 14:59:31.694: ERROR/AndroidRuntime(323):     at android.os.AsyncTask.access$300(AsyncTask.java:127)
03-14 14:59:31.694: ERROR/AndroidRuntime(323):     at android.os.AsyncTask$InternalHandler.handleMessage(AsyncTask.java:429)
03-14 14:59:31.694: ERROR/AndroidRuntime(323):     at android.os.Handler.dispatchMessage(Handler.java:99)
03-14 14:59:31.694: ERROR/AndroidRuntime(323):     at android.os.Looper.loop(Looper.java:123)
03-14 14:59:31.694: ERROR/AndroidRuntime(323):     at android.app.ActivityThread.main(ActivityThread.java:4627)
03-14 14:59:31.694: ERROR/AndroidRuntime(323):     at java.lang.reflect.Method.invokeNative(Native Method)
03-14 14:59:31.694: ERROR/AndroidRuntime(323):     at java.lang.reflect.Method.invoke(Method.java:521)
03-14 14:59:31.694: ERROR/AndroidRuntime(323):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868)
03-14 14:59:31.694: ERROR/AndroidRuntime(323):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626)
03-14 14:59:31.694: ERROR/AndroidRuntime(323):     at dalvik.system.NativeStart.main(Native Method)

1 个答案:

答案 0 :(得分:3)

您的Data.class没有正确编写以正确解析您的json数据。您需要以下结构才能获得所有响应。

您需要使用以下类来获取结果数据。

Gson gson = new Gson();
Data data = gson.fromJson(jsonString,Data.class);

这是您的数据类

 public class Data {

 @SerializedName("data")
 public List<ResultData> mResultData;
}

  public class ResultData {

    @SerializedName("atb_atestwebservice_cities")
    public List<City> mCityList;

    @SerializedName("atb_atestwebservice_states")
    public List<State> mStateList;

  }


public class City {

/*"id": "3",
"cities": "Ajmer",
"date": "2012-03-01 19:30:32"*/

    @SerializedName("id")
    public String id;

    @SerializedName("cities")
    public String mCitie;

    @SerializedName("date")
    public String mData;

}


  public class State {


/*"id": "2",
"states": "goa",
"date": "2012-02-28 12:53:51"*/

@SerializedName("id")
public String id;

@SerializedName("states")
public String mState;

@SerializedName("date")
public String mDate;

 }

您需要在包中添加所有这些课程。