akshaybhange

var productData = MediatorLiveData<Resource<Product>>()

init {        
  fetchData()
}

fun fetchData() {
    productData.addSource(productRepository.getproduct(id)) {
        productData.value = it
    }

akshaybhange

fun getProduct(id:Int): LiveData<Resource<Product>> { 
        val productData = MutableLiveData<Resource<Product>>()
        productData.value = Resource.Loading()
        productWebService
            .getProduct(id)
            .enqueue(object : Callback<Product> {
                override fun onResponse(
                    call: Call<Product>,
                    response: Response<JsonObject>
                ) {

akshaybhange

sealed class Resource<T>(
    val data: T? = null,
    val message: String? = null
) {
    class Success<T>(data: T) : Resource<T>(data)
    class Loading<T>(data: T? = null) : Resource<T>(data)
    class Error<T>(message: String, data: T? = null) : Resource<T>(data, message)
}

enum class Status {

akshaybhange

private void subscribeToModel() {
  // Observe product data
  viewModel.getObservableProduct().observe(getViewLifecycleOwner(), new Observer<Product>() {
      @Override
      public void onChanged(@Nullable Product product) {
        mTitle.setText(product.title);
      }
  });
}

akshaybhange

//this is wrong
//writing logic for filtering items in your Fragmet 
var filterList = simpleList.filter { it%2 == 0 }

//this is correct
//function created for it in your ViewModel
fun getEvenNumbers(simpleList : List<Int>):List<Int> {
    return simpleList.filter { it%2 == 0 }
}