Orientation change is not preserved while using viewmodel - viewmodel

Question

New to MVVM clean archietecture .Building an app which has single screen consisting of Recycler view. The data is fetched through retrofit.According to the documentation ViewModel is able to live through the configuration changes but in my case it is not working when i change orientation from portrait to landscape. No clue about the issue, Please advise
**NewsViewModel.Kt**
import android.util.Log
import androidx.lifecycle.*
import com.example.recyclerviewjsonarray.model.NewsList
import com.example.recyclerviewjsonarray.network.remote.RetrofitInstanceDto
import com.example.recyclerviewjsonarray.network.remote.RetrofitServiceDto
import kotlinx.coroutines.Dispatchers
import kotlinx.coroutines.delay
import kotlinx.coroutines.launch
private const val TAG ="NewsViewModel"
//viewmodel for handling clean archietecture
class NewsViewModel : ViewModel() {
//Mutable live data for the news list
private val _newsMutableLiveData: MutableLiveData<NewsList> = MutableLiveData()
val newsMutableLiveData : LiveData<NewsList> get() =
_newsMutableLiveData
//viewmodel will observe the latest updated data with the help of mutable live data
fun newsListObserver(): LiveData<NewsList> {
return newsMutableLiveData
}
/* making an api call using viewmodel scope (custom coroutines scope can be used as well)
launch is like a builder . Here it is launching Dispatcher.IO for memory intensive operation
Now inside we will create synchronized retrofit instance and fetch the response
in the form of getDataFromApi() with a delay of 2 seconds respectively
post value is called lastly for setting the value from a background thread */
fun getDataFromApi() {
Log.i(TAG,"init")
viewModelScope.launch(Dispatchers.IO) {
val retrofitInstance = RetrofitInstanceDto.getRetrofitInstance().create(RetrofitServiceDto::class.java)
val response = retrofitInstance.getDataFromApi()
delay(1500)
_newsMutableLiveData.postValue(response)
}
}
**NewsListFragment.kt**
import android.os.Bundle
import android.util.Log
import android.view.*
import androidx.fragment.app.Fragment
import android.widget.Toast
import androidx.fragment.app.viewModels
import androidx.recyclerview.widget.LinearLayoutManager
import com.example.recyclerviewjsonarray.R
import com.example.recyclerviewjsonarray.databinding.FragmentNewsListBinding
import com.example.recyclerviewjsonarray.model.NewsList
import kotlinx.android.synthetic.main.fragment_news_list.*
private const val TAG ="NewsListFragment"
//The view of MVVM architecture
class NewsListFragment : Fragment() {
/* view binding with late init as dont want to redraw again n again
also late init promises no nullable data when it is called later */
private lateinit var binding: FragmentNewsListBinding
//Kotlin property delegate used to define viewmodels
private val viewmodel: NewsViewModel by viewModels()
private lateinit var newsAdapter: NewsListAdapter
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setHasOptionsMenu(true)
}
override fun onCreateView(
inflater: LayoutInflater, container: ViewGroup?,
savedInstanceState: Bundle?,
): View {
binding = FragmentNewsListBinding.inflate(layoutInflater)
Log.i(TAG,"onCreate")
//Creating the observer which updates the UI(Main Thread)
viewmodel.newsMutableLiveData.observe(viewLifecycleOwner, {
if(it!=null )
{
hideProgressBar()
Log.i(TAG,"Received the data")
initAdapterModel()
newsAdapter.setLatestData(it.rows,activity)
}
else {
showProgressBar()
Toast.makeText(activity,"No data",Toast.LENGTH_LONG).show()
}
})
viewmodel.getDataFromApi()
return binding.root
}
override fun onPause() {
super.onPause()
}
//Binding the recycler view adapter and with the news adapter
private fun initAdapterModel() {
binding.recyclerView.layoutManager = LinearLayoutManager(requireContext())
newsAdapter = NewsListAdapter()
binding.recyclerView.adapter = newsAdapter
}
private fun hideProgressBar() {
progressBar.visibility = View.INVISIBLE
}
private fun showProgressBar() {
progressBar.visibility = View.VISIBLE
}
override fun onCreateOptionsMenu(menu: Menu, inflater: MenuInflater) {
inflater.inflate(R.menu.scrolltotop,menu)
super.onCreateOptionsMenu(menu, inflater)
}
override fun onOptionsItemSelected(item: MenuItem): Boolean {
binding.recyclerView.smoothScrollToPosition(0)
return super.onOptionsItemSelected(item)
}
companion object {
#JvmStatic
fun newInstance() =
NewsListFragment()
}
}
}

Answer 1

Well I found the solution by using event and save instance state.