How to solve retrofit Conversion Exception when converting to json string

Question

I am trying to post a set of parameters to api and I am getting an error that I do not quite understand

java.lang.RuntimeException: retrofit.converter.ConversionException: com.google.gson.JsonSyntaxException: java.lang.IllegalStateException: Expected BEGIN_OBJECT but was STRING at line 1 column 1 path $

I am suspecting three areas that might be causing this error

1. I have either declared that last parameter incorrectly

   @Query("AppTimes") String appTimes

2. My Gson conversion result is not correct and perhaps I should use another converter

3. It is not possible to convert a java list to json

This is what my rest adapter looks like

public static DigitechService createService(Context context)
   {
      Gson gson = new GsonBuilder()
            //.setDateFormat("yyyy'-'MM'-'dd'T'HH':'mm':'ss'.'SSS'Z'")
            .setDateFormat("yyyy-MM-dd'T'HH:mm:ss") // 2015-02-23T00:00:00
            .create();

      // Only allow LogLevel for Debug
      RestAdapter restAdapter = new RestAdapter.Builder()
            .setLogLevel(Globals.TEST == false ? RestAdapter.LogLevel.NONE : RestAdapter.LogLevel.FULL)
            .setEndpoint(Globals.digitechApiBaseUrl)
            .setConverter(new GsonConverter(gson))
            .setRequestInterceptor(new AuthRequestInterceptor(context))
            .build();

      return restAdapter.create(DigitechService.class);
   }

This is my interface

@POST("/api/v1/LoadAppTimeUsage/")
    void loadAppTimeUsage(
            @Query("cellPhoneNumber") String cellPhoneNumber,
            @Query("appName") String appName,
            @Query("timeSpent") int timeSpent,
            @Query("AppTimes") String appTimes,
            Callback<List<ResultPost>> cb
    );

My post method

public List<AppTimeUsage> postAppTimeUsage(List<AppTimeUsage> atu)
    {
        String json = new Gson().toJson(atu);
        TinyDB settings = new TinyDB(mContext);
        // Show progress
       final ProgressDialog progress = new ProgressDialog(mContext);
        progress.setOnCancelListener(new DialogInterface.OnCancelListener() {
            @Override
            public void onCancel(DialogInterface dialog) {

            }
        });
        progress.show();


        String cellphoneNumber = settings.getString(AppPreferences.CONFIRMED_CellPhoneNUmber);


        DigiTechClient.createService(mContext).loadAppTimeUsage(cellphoneNumber, appName ,timeSpent,  json, new Callback<List<ResultPost>>() {
            @Override
            public void success(List<ResultPost> resultPosts, Response response) {
                if (progress != null) progress.dismiss();
            }

            @Override
            public void failure(RetrofitError error) {
                if (progress != null) progress.dismiss();

                DeviceApp.handleError(error);

                if (error.getResponse() != null) {
                    RestError err = (RestError) error.getBodyAs(RestError.class);

                    Toast.makeText(mContext, err.Message, Toast.LENGTH_LONG).show();
                } else {
                    Toast.makeText(mContext, error.getMessage(), Toast.LENGTH_LONG).show();
                }
            }
        });
        return atu;
    }

My StackTrace

    java.lang.RuntimeException: retrofit.converter.ConversionException: com.google.gson.JsonSyntaxException: java.lang.IllegalStateException: Expected BEGIN_OBJECT but was STRING at line 1 column 1 path $
at com.xera.deviceinsight.structs.AppTimeUsageRecorder$2.failure(AppTimeUsageRecorder.java:163)
at retrofit.CallbackRunnable$2.run(CallbackRunnable.java:53)
at android.os.Handler.handleCallback(Handler.java:730)
at android.os.Handler.dispatchMessage(Handler.java:92)
at android.os.Looper.loop(Looper.java:176)
at android.app.ActivityThread.main(ActivityThread.java:5419)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:525)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1046)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:862)
at dalvik.system.NativeStart.main(Native Method)
Caused by: retrofit.converter.ConversionException: com.google.gson.JsonSyntaxException: java.lang.IllegalStateException: Expected BEGIN_OBJECT but was STRING at line 1 column 1 path $
at retrofit.converter.GsonConverter.fromBody(GsonConverter.java:67)
at retrofit.RetrofitError.getBodyAs(RetrofitError.java:137)
at com.xera.deviceinsight.structs.AppTimeUsageRecorder$2.failure(AppTimeUsageRecorder.java:163) 
at retrofit.CallbackRunnable$2.run(CallbackRunnable.java:53) 
at android.os.Handler.handleCallback(Handler.java:730) 
at android.os.Handler.dispatchMessage(Handler.java:92) 
at android.os.Looper.loop(Looper.java:176) 
at android.app.ActivityThread.main(ActivityThread.java:5419) 
at java.lang.reflect.Method.invokeNative(Native Method) 
at java.lang.reflect.Method.invoke(Method.java:525) 
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1046) 
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:862) 
at dalvik.system.NativeStart.main(Native Method) 
Caused by: com.google.gson.JsonSyntaxException: java.lang.IllegalStateException: Expected BEGIN_OBJECT but was STRING at line 1 column 1 path $
at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory$Adapter.read(ReflectiveTypeAdapterFactory.java:200)
at com.google.gson.Gson.fromJson(Gson.java:810)
at com.google.gson.Gson.fromJson(Gson.java:775)
at retrofit.converter.GsonConverter.fromBody(GsonConverter.java:63)
at retrofit.RetrofitError.getBodyAs(RetrofitError.java:137) 
at com.xera.deviceinsight.structs.AppTimeUsageRecorder$2.failure(AppTimeUsageRecorder.java:163) 
at retrofit.CallbackRunnable$2.run(CallbackRunnable.java:53) 
at android.os.Handler.handleCallback(Handler.java:730) 
at android.os.Handler.dispatchMessage(Handler.java:92) 
at android.os.Looper.loop(Looper.java:176) 
at android.app.ActivityThread.main(ActivityThread.java:5419) 
at java.lang.reflect.Method.invokeNative(Native Method) 
at java.lang.reflect.Method.invoke(Method.java:525) 
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1046) 
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:862) 
at dalvik.system.NativeStart.main(Native Method) 
Caused by: java.lang.IllegalStateException: Expected BEGIN_OBJECT but was STRING at line 1 column 1 path $
at com.google.gson.stream.JsonReader.beginObject(JsonReader.java:387)
at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory$Adapter.read(ReflectiveTypeAdapterFactory.java:189)
at com.google.gson.Gson.fromJson(Gson.java:810) 
at com.google.gson.Gson.fromJson(Gson.java:775) 
at retrofit.converter.GsonConverter.fromBody(GsonConverter.java:63) 
at retrofit.RetrofitError.getBodyAs(RetrofitError.java:137) 
at com.xera.deviceinsight.structs.AppTimeUsageRecorder$2.failure(AppTimeUsageRecorder.java:163) 
at retrofit.CallbackRunnable$2.run(CallbackRunnable.java:53) 
at android.os.Handler.handleCallback(Handler.java:730) 
at android.os.Handler.dispatchMessage(Handler.java:92) 
at android.os.Looper.loop(Looper.java:176) 
at android.app.ActivityThread.main(ActivityThread.java:5419) 
at java.lang.reflect.Method.invokeNative(Native Method) 
at java.lang.reflect.Method.invoke(Method.java:525) 
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1046) 
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:862) 
at dalvik.system.NativeStart.main(Native Method) 

Answer 1

Don't convert the parameter to a JSON string. Instead, send the list object as a body parameter and it will automatically be converted to JSON.

As an example:

@POST("/api/v1/LoadAppTimeUsage/")
void loadAppTimeUsage(
        @Body List<MyApp> appTimes,
        Callback<List<ResultPost>> cb
);

Answer 2

I think it is your gson converter occurs problem. My retrofit version is different. I solve it by: builder.addConverterFactory(GsonConverterFactory.create(Gsons.getGson())); Hope it can help you.