java.lang.ClassCastException: com.google.gson.internal.LinkedTreeMap cannot be cast to model class android

Question

I am passing the response of an API call (Retrofit used) to a class and trying to cast it to my model class. Since i am using retrofit for the API call, it generates a linked hashmap based on the response from the server prior to convert it into model class object using Gson. (That is what i understand, correct me if i am wrong). I have attached an image of what i can see when i debug with the response object. How can i convert this response into an object of my model class or type Object. I am getting class cast exception when i attempt to cast type Object into my model class inside my activity.

Here is my code

API Call

call.enqueue(new Callback() {

        @Override
        public void onResponse(Call call, Response response) {
            if (response.body() != null) {   
                        List<CategoriesBaseModel> categoryBaseResponseList = (List<CategoriesBaseModel>) response.body();
                        List<Object> categoryResponseList = (List<Object>) categoryBaseResponseList.get(0).getData();
                        if (categoryResponseList != null) {
                           mCategoriesInterface.passCategoriesResponse(categoryResponseList, "HomeFragment");
                        }
            }                
        }
        @Override
        public void onFailure(Call call, Throwable t) {

            call.cancel();
        }
    });

Activity

CategoriesInterface categoriesInterface = new CategoriesInterface() {
    @Override
    public void passCategoriesResponse(List<Object> scheduleList, String name) {
        CategoriesModel categoriesModel;
        for (Object model : scheduleList){
            categoriesModel = (CategoriesModel) model;
            Log.d("TAG", "");
        }
    }
};

see this page, perheaps he give you an answer : https://stackoverflow.com/questions/32444863/google-gson-linkedtreemap-class-cast-to-myclass — vincent091, Jan 11 '18 at 09:41
Does the error occur exactly on this line?: `categoriesModel = (CategoriesModel) model;` — gil.fernandes, Jan 11 '18 at 09:44
The problem is it cannot be accessed as a hash map and the exception raises if i cast object — Pramod Moolekandathil, Jan 11 '18 at 10:03
Whilst this is not a great solution: you can convert manually the `LinkedTreeMap` to a `CategoriesModel` object. That is definitely possible, but not the most elegant solution. You can just go and cast the `model` object to a `java.util.Map` and then happily get each field. — gil.fernandes, Jan 11 '18 at 10:18

score 0 · Answer 1 · answered Jan 11 '18 at 10:46

0

Solved this by converting the Object into Json string and coverting it back directly to the model class object.

Gson gs = new Gson();
String js = gs.toJson(model);
categoriesModel = gs.fromJson(js, CategoriesModel.class);

answered Jan 11 '18 at 10:46

Pramod Moolekandathil

569
5
14

Whilst the code is compact, this is not a very performant option. You serialize and then deserialize. It might not make much difference, if you do not have much data, but if you do, this is quite bad for performance. – gil.fernandes Jan 11 '18 at 10:53

java.lang.ClassCastException: com.google.gson.internal.LinkedTreeMap cannot be cast to model class android

API Call

Activity

1 Answers1