Wsrtjtyk

I am using MVVM architecture to hit a web service through retrofit in android studio. I have handled the response of the service in my view class. But the problem i am facing is how to handle the exceptions and pass them to my view class. One way is to make constructor in my Bean class and pass both the response and error to it and update UI. But i want more optimised way to handle exceptions inside UI.

Here is my repository code :

final MutableLiveData<MyBeanClass> myBeanClass = new MutableLiveData<>();

   ApiInterface apiInterface = ApiClient.getClientAuthentication().create(ApiInterface.class);

    Call<MyBeanClass> call = apiInterface.getData(id);

    call.enqueue(new Callback<MyBeanClass>() {

        @Override

        public void onResponse(Call<MyBeanClass> call, Response<MyBeanClass> response) {

            if(response.body()!=null) {

                myBeanClass.setValue(response.body());

            }

        }



        @Override

        public void onFailure(Call<MyBeanClass> call, Throwable t) {

         //How to handle exceptions here and pass the exception to UI without making constructor in bean class

        }

    });



    return myBeanClass;

Check out how it can be done from your repository code :

//Take it globally in your repository class, and provide getter for it.

final MutableLiveData<MyBeanClass> myBeanClass = new MutableLiveData<>();

final MutableLiveData<Throwable> error = new MutableLiveData<>();



public void someApiCallMethod() {

    // In your method call for API

    ApiInterface apiInterface = 

    ApiClient.getClientAuthentication().create(ApiInterface.class);

    Call<MyBeanClass> call = apiInterface.getData(id);

    call.enqueue(new Callback<MyBeanClass>() {

        @Override

        public void onResponse(Call<MyBeanClass> call, Response<MyBeanClass> response) {

            if(response.body()!=null) {

                myBeanClass.setValue(response.body());

            }

            // Even you can handle your response error if it's in your response.

        }



        @Override

        public void onFailure(Call<MyBeanClass> call, Throwable t) {

            //Set your error live data from here

            error.setValue(t);

        }

    });

}

From your ViewModel Class, make a method that calls your repo API method and another to provide your live data to be observed on your UI.

Hope it helps !.

Instead of creating two Mutable classes.
You can just create a wrapper object for both error and success state or even loading state

data class Resource<out T>(val status: Status, val data: T?, val message: String?) {

    companion object {

        fun <T> success(data: T?): Resource<T> {

            return Resource(SUCCESS, data, null)

        }



        fun <T> error(msg: String, data: T?): Resource<T> {

            return Resource(ERROR, data, msg)

        }



        fun <T> loading(data: T?): Resource<T> {

            return Resource(LOADING, data, null)

        }

    }

}

And then use MutableLive data as this type

final MutableLiveData<Resource<MyBeanClass>> myBeanClass = new MutableLiveData<>();

           ApiInterface apiInterface = ApiClient.getClientAuthentication().create(ApiInterface.class);

            Call<MyBeanClass> call = apiInterface.getData(id);

            call.enqueue(new Callback<MyBeanClass>() {

                @Override

                public void onResponse(Call<MyBeanClass> call, Response<MyBeanClass> response) {

                    if(response.body()!=null) {

                    myBeanClass.setValue(Resource<MyBeanClass>.success(response.body));

                    }

                }



                @Override

                public void onFailure(Call<MyBeanClass> call, Throwable t) {

     myBeanClass.setValue(Resource<MyBeanClass>.error(t.getLocalizedMessage()));

                }

            });



            return myBeanClass;

You can check out this google sample
https://github.com/googlesamples/android-architecture-components/tree/master/GithubBrowserSample