Question

I am developing application in which i am use Gson parsing for serialize json object which contain array of some data.. but here some issue with method that i am parse… it not getting me successfully parse.. i have never tried to parse json data with Gson library with Serialize annotation.can you please let me know where is my mistak…

here is code..

    InputStream source = retrieveStream(url);

    Gson gson = new Gson();

    Reader reader = new InputStreamReader(source);
    GetAllAssetsResult response = gson.fromJson(reader, GetAllAssetsResult.class);

   private InputStream retrieveStream(String url) {

    DefaultHttpClient client = new DefaultHttpClient(); 

    HttpGet getRequest = new HttpGet(url);

    try {

           HttpResponse getResponse = client.execute(getRequest);
           final int statusCode = getResponse.getStatusLine().getStatusCode();

           if (statusCode != HttpStatus.SC_OK) { 
              Log.w(getClass().getSimpleName(), 
                  "Error " + statusCode + " for URL " + url); 
              return null;
           }

           HttpEntity getResponseEntity = getResponse.getEntity();
           return getResponseEntity.getContent();

    } 
    catch (IOException e) {
       getRequest.abort();
       Log.w(getClass().getSimpleName(), "Error for URL " + url, e);
    }

    return null;

 }

here is Serialize annotaion base Pojo:

  package com.DemoGsonLib;

    import java.util.List;

    import com.google.gson.annotations.SerializedName;

        public class GetAllAssetsResult {

            public List<GetAllAssetsResult> getAllAssetsResult;

                @SerializedName("ATCOCode")
                public String ATCOCode;

                @SerializedName("AssetID")
                public String AssetID;

                @SerializedName("Bearing")
                public String Bearing;

                @SerializedName("CommonName")
                public String CommonName;

                @SerializedName("Locality")
                public String Locality;

                @SerializedName("Location")
                public String Location;

                @SerializedName("SMSNumber")
                public String SMSNumber;

                @SerializedName("Street")
                public String Street;
        }

Json Data :

{
  "GetAllAssetsResult": [
    {
      "ATCOCode": null,
      "AssetID": 1,
      "Bearing": null,
      "CommonName": null,
      "Locality": null,
      "Location": null,
      "SMSNumber": "Little Clare",
      "Street": null
    },
    {
      "ATCOCode": "34000000002",
      "AssetID": 2,
      "Bearing": null,
      "CommonName": "Gloucester Green Bus Station",
      "Locality": "Oxford City Centre",
      "Location": "50.4913",
      "SMSNumber": "oxfagwdw",
      "Street": "Gloucester Green"
    },
    {

Error

11-16 13:16:26.805: WARN/System.err(1762): java.lang.NullPointerException
11-16 13:16:26.805: WARN/System.err(1762):     at com.DemoGsonLib.DemoGsonLibActivity.onCreate(DemoGsonLibActivity.java:39)
11-16 13:16:26.805: WARN/System.err(1762):     at android.app.Activity.performCreate(Activity.java:4533)
11-16 13:16:26.805: WARN/System.err(1762):     at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1053)
11-16 13:16:26.805: WARN/System.err(1762):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1934)
11-16 13:16:26.805: WARN/System.err(1762):     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1995)
11-16 13:16:26.805: WARN/System.err(1762):     at android.app.ActivityThread.access$600(ActivityThread.java:128)
11-16 13:16:26.805: WARN/System.err(1762):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1161)
11-16 13:16:26.805: WARN/System.err(1762):     at android.os.Handler.dispatchMessage(Handler.java:99)
11-16 13:16:26.805: WARN/System.err(1762):     at android.os.Looper.loop(Looper.java:137)
11-16 13:16:26.805: WARN/System.err(1762):     at android.app.ActivityThread.main(ActivityThread.java:4517)
11-16 13:16:26.805: WARN/System.err(1762):     at java.lang.reflect.Method.invokeNative(Native Method)
11-16 13:16:26.805: WARN/System.err(1762):     at java.lang.reflect.Method.invoke(Method.java:511)
11-16 13:16:26.805: WARN/System.err(1762):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:993)
11-16 13:16:26.805: WARN/System.err(1762):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:760)
11-16 13:16:26.805: WARN/System.err(1762):     at dalvik.system.NativeStart.main(Native Method)

Answer 1

You are not considering the fact that there’s a Json Array that need to be serialized in your pojo

The following code should work

public class GetAllAssetsResult
{
    @SerializedName("GetAllAssetsResult")
    public List<Asset> assets;

    class Asset
    {
        @SerializedName("ATCOCode")
        public String ATCOCode;

        @SerializedName("AssetID")
        public String AssetID;

        @SerializedName("Bearing")
        public String Bearing;

        @SerializedName("CommonName")
        public String CommonName;

        @SerializedName("Locality")
        public String Locality;

        @SerializedName("Location")
        public String Location;

        @SerializedName("SMSNumber")
        public String SMSNumber;

        @SerializedName("Street")
        public String Street;
    }
}