Paging Library Callback.OnResult Not Returning Value To Livedata

Question

I wanna to implement jetpack paging library.

everything seems working, after getting response from api (using Retrofit2 and coroutine) android paging callback is calling his onResult interface.

but it's not returning it's value to livedata in main activity when data received.

What is the solution ?

ViewModel

    fun getListData(): LiveData<PagedList<DataListModel>> {
        return initializedPagedListBuilder(PagingConfig.config).build()
    }


    private fun initializedPagedListBuilder(config: PagedList.Config): LivePagedListBuilder<Int, DataListModel> {

        val dataSourceFactory = object : DataSource.Factory<Int, DataListModel>() {
            override fun create(): DataSource<Int, DataListModel> {
                return ListDataPageSource()
            }
        }
        return LivePagedListBuilder<Int, DataListModel>(dataSourceFactory, config)
    }

ListDataPageSource

class ListDataPageSource : PageKeyedDataSource<Int, DataListModel>() {

    override fun loadInitial(
        params: LoadInitialParams<Int>,
        callback: LoadInitialCallback<Int, DataListModel>
    ) {
        val apiCall = RetrofitApi.getApiList("http://jsonplaceholder.typicode.com/").create(
            MoviesApi::class.java
        )

        CoroutineScope(Dispatchers.IO).launch {
            val response = apiCall.getDataList(params.requestedLoadSize, 10)
            if (response.isSuccessful && response.body() != null) {
                callback.onResult(response.body()!!, null, 1)
            }
        }
    }

    override fun loadAfter(
        params: LoadParams<Int>,
        callback: LoadCallback<Int, DataListModel>
    ) {
        val apiCall = 
          RetrofitApi.getApiList("http://jsonplaceholder.typicode.com/").create(MoviesApi::class.java)

        CoroutineScope(Dispatchers.IO).launch {
            val response = apiCall.getDataList(params.key + 10, 10)
            if (response.isSuccessful && response.body() != null) {
                callback.onResult(response.body()!!, params.key)

            }
        }
    }

    override fun loadBefore(
        params: LoadParams<Int>,
        callback: LoadCallback<Int, DataListModel>
    ) {

    }

MainActivity

override fun onCreate(savedInstanceState: Bundle?) {
       super.onCreate(savedInstanceState)
       setContentView(R.layout.activity_main)
       val adapter = ListDataAdapter()
       MainRecyclerView.adapter = adapter

       val viewModel = ViewModelProviders.of(this).get(MainViewModel::class.java)
       val liveData = viewModel.getListData()
       liveData.observe(this, Observer {
           adapter.submitList(it)
       })

   }

PagingConfig

 companion object{
        val config = PagedList.Config.Builder()
            .setPageSize(10)
            .setInitialLoadSizeHint(10)
            .setEnablePlaceholders(false)
            .build()
    }