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Using Flow, the list is not reloaded in the recyclerView

I am training with a simple app to show movies, I use an MVVM pattern and Flow.
Problem
This is my home, filterable through chips
I click on a movie , the details screen comes up then I go back to the home and this is the result:
Using logcat the home screen gets the list of movies to show but is not shown in the recyclerview (which uses diffUtil).
Below is the code for my fragment:
#AndroidEntryPoint
class Home2Fragment : Fragment() {
private val TAG = Home2Fragment::class.simpleName
private var _binding: FragmentHome2Binding? = null
private val binding: FragmentHome2Binding
get() = _binding!!
private val viewModel: HomeViewModel by viewModels()
override fun onCreateView(
inflater: LayoutInflater, container: ViewGroup?,
savedInstanceState: Bundle?
): View {
// Inflate the layout for this fragment
_binding = FragmentHome2Binding.inflate(inflater, container, false)
return binding.root
}
override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
super.onViewCreated(view, savedInstanceState)
binding.apply {
initChipGroupSpecificMovieList()
val adapter = MovieAdapter()
sectionRv.setHasFixedSize(true)
sectionRv.adapter = adapter
viewLifecycleOwner.lifecycleScope.launch {
viewLifecycleOwner.lifecycle.repeatOnLifecycle(Lifecycle.State.STARTED) {
viewModel.movieListBySpecification.collectLatest {
Log.d(TAG, "onViewCreated: received list")
adapter.addItems(it)
}
}
}
}
}
private fun FragmentHome2Binding.initChipGroupSpecificMovieList() {
val sortByMap = HomeViewModel.Companion.MovieListSpecification.values()
chipGroup.removeAllViews()
for (specification in sortByMap) {
val chip = Chip(context)
chip.isCheckable = true
chip.id = specification.ordinal
chip.text = getString(specification.nameResource)
chip.setOnCheckedChangeListener { _, isChecked ->
if (isChecked)
viewModel.setMovieListSpecification(specification)
}
chipGroup.addView(chip)
}
chipGroup.check(sortByMap.lastIndex - sortByMap.size + 1)//check first element
}
override fun onDestroyView() {
super.onDestroyView()
_binding = null
}
}
it seems at the line of code where I try to insert the list of movies in the adapter this doesn't add them because maybe via diffUtil it finds that it is the previous list and so it doesn't load it. However it doesn't show the previous one either, possible solutions?

as java code you can use this
#Override
public void onResume() {
super.onResume();
if(it.size() > 0) {
adapter.addItems(it)
}
}

Problem with data persisting when returning after navigating a fragment

I am repeating the process of adding and completing the list on the detail screen.
The problem is that the previous list remains intact in the newly created detail fragment.
For example, if i made 3 lists in the previous detail screen, adding data in the new detail screen will add them to a list of size 3.
I've tried various things, but I still don't know what could be the cause.
Fragment
class WriteDetailFragment : Fragment() {
...
private val viewModel: WriteDetailViewModel by viewModels {
WriteDetailViewModelFactory(
(requireActivity().application as WorkoutApplication).writeDetailRepo
)
}
override fun onCreateView(
inflater: LayoutInflater, container: ViewGroup?,
savedInstanceState: Bundle?
): View? {
_binding = FragmentWriteDetailBinding.inflate(inflater, container, false)
binding.apply {
adapter = DetailAdapter()
rv.adapter = adapter
rv.itemAnimator = null
// add set
addSet.setOnClickListener {
viewModel.addSet()
}
// complete
complete.setOnClickListener {
findNavController().navigate(R.id.action_writeDetailFragment_to_addRoutineFragment)
}
}
return binding.root
}
override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
super.onViewCreated(view, savedInstanceState)
viewLifecycleOwner.lifecycleScope.launch {
repeatOnLifecycle(Lifecycle.State.STARTED) {
viewModel.items.collect { list ->
adapter.submitList(list)
}
}
}
}
}
ViewModel
class WriteDetailViewModel(
private val repository: WriteDetailRepository
): ViewModel() {
private var _items: MutableStateFlow<List<WorkoutSetInfo>> = MutableStateFlow(listOf())
val items = _items.asStateFlow()
fun addSet() {
viewModelScope.launch(Dispatchers.IO) {
repository.add()
_items.value = repository.getList()
}
}
}
Repository
class WriteDetailRepository(val dao: WorkoutDao) {
private var setInfoList = ArrayList<WorkoutSetInfo>()
private lateinit var updatedList: List<WorkoutSetInfo>
fun add() {
val item = WorkoutSetInfo(set = setInfoList.size + 1)
setInfoList.add(item)
updatedList = setInfoList.toList()
}
fun getList() : List<WorkoutSetInfo> = updatedList
}

recyclerview not visible at run time

I implemented a simple recyclerview using databinding using kotlin language.
In xml, recyclerview seems to be the default,
but when I run it, it doesn't show up as default.
Other buttons and views included in the fragment appear normally when executed, but only the recyclerview is not visible. Which part is wrong?
class WorkFragment : Fragment() {
private var _binding: FragmentWorkBinding? = null
private val binding get() = _binding!!
override fun onCreateView(
inflater: LayoutInflater,
container: ViewGroup?,
savedInstanceState: Bundle?
): View? {
_binding = FragmentWorkBinding.inflate(inflater, container, false)
val view = binding.root
return view
}
override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
super.onViewCreated(view, savedInstanceState)
val data = mutableListOf<WorkList>()
val adapter = WorkAdapter()
adapter.data = data
binding.recycler1.adapter = adapter
binding.recycler1.layoutManager = LinearLayoutManager(requireContext())
}
}
class WorkAdapter : RecyclerView.Adapter<WorkAdapter.ViewHolder>() {
var data = mutableListOf<WorkList>()
class ViewHolder(val binding: RecyclerviewWorkItemBinding) : RecyclerView.ViewHolder(binding.root) {
fun bind(workList: WorkList) {
binding.tvStarttime.text = workList.Starttime
binding.tvAdmin.text = workList.Admin
binding.tvPart.text = workList.Part
binding.tvStoptime.text = workList.Stoptime
binding.tvWorkers.text = workList.Workers.toString()
}
}
override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): WorkAdapter.ViewHolder {
val binding = RecyclerviewWorkItemBinding.inflate(LayoutInflater.from(parent.context), parent, false)
return ViewHolder(binding)
}
override fun onBindViewHolder(holder: WorkAdapter.ViewHolder, position: Int) {
holder.bind(data[position])
}
override fun getItemCount(): Int {
return data.size
}
// fun replaceList(newList: MutableList<WorkList>) {
// data = newList.toMutableList()
// notifyDataSetChanged()
// }
}
Is there something wrong with my code?
For reference, I just used a fragment, not an activity.

its typically for the RecyclerView to behave like its hidden but actually its not. the reason is you are passing an empty list so the recycler will not be extended or show because there is no items in the list.

LiveData + ViewModel States , values clash and only last value is observed

Im using ViewModel with states and LiveData with one observer .
I have an activity and a fragment . everything works fine until Im rotating the screen
and then, the states I want to observe , clash.
What can I do in order to prevent it and make it work as expected?
I know I can add more observers but I don't want to solve it in this way , it may lead to problems with the other code.
MainActivity code :
private var appsDetailsHmap = HashMap< String , AppsDetails>()
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
progressBar = CircleProgressBarDialog(this)
viewModel.getState().observe(this, Observer {state->
when(state){
is SettingsViewModelStates.GetAppsDetails->initUI(state.list)
is SettingsViewModelStates.ShowDialog->progressBar.showOrHide(state.visibility)
is SettingsViewModelStates.GetCachedData->setCachedSettings(state.appDetailsHmap,state.selectedApp,state.speechResultAppName)
}
})
if (savedInstanceState==null){
viewModel.initSettingsActivityUI(appsDetailsHmap)
}
else{
viewModel.initCachedSettingsActivityUI()
}
Fragment code
override fun onCreateView(
inflater: LayoutInflater, container: ViewGroup?,
savedInstanceState: Bundle?
): View? {
// Inflate the layout for this fragment
val view= inflater.inflate(R.layout.fragment_added_apps, container, false)
viewModel.getCachedApplist()
return view
}
override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
super.onViewCreated(view, savedInstanceState)
viewModel.getState().observe(viewLifecycleOwner, Observer {state->
when(state){
is SettingsViewModelStates.PassAppsToFragment->{
initRecyclerView(state.list)
}
}
})
}
ViewModel
private var state=MutableLiveData<SettingsViewModelStates>()
private var appsDetailsHmap=HashMap<String,AppsDetails>()
private var addedApps= HashMap<String,Drawable?>()
fun getState()=state as LiveData<SettingsViewModelStates>
fun getCachedApplist(){
if (addedApps.isEmpty()){
getAppsList()
println("empty")
}
else
state.setValue(SettingsViewModelStates.PassAppsToFragment(addedApps))
}
fun initCachedSettingsActivityUI(){
state.setValue(SettingsViewModelStates.GetCachedData(appsDetailsHmap,selectedApp,speechResultAppName))
}
fun initSettingsActivityUI(list:HashMap<String, AppsDetails>) {
appsDetailsHmap=list
state.setValue( SettingsViewModelStates.GetAppsDetails(list))
}
states:
sealed class SettingsViewModelStates {
data class GetAppsDetails(val list:HashMap<String, AppsDetails>):SettingsViewModelStates()
data class ShowDialog(val visibility: Int) : SettingsViewModelStates()
data class PassAppsToFragment(val list:HashMap<String,Drawable?>) : SettingsViewModelStates()
data class GetCachedData(val appDetailsHmap:HashMap<String,AppsDetails>,
val selectedApp: AppsDetails,
val speechResultAppName:String ) : SettingsViewModelStates()
}

On clearing the data in search view, it should erase the filtered list and populate the original list

HomeFragment.kt
override fun onCreateView(
inflater: LayoutInflater,
container: ViewGroup?,
savedInstanceState: Bundle?
): View? {
return setupBindings(inflater, container, savedInstanceState)
}
override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
super.onViewCreated(view, savedInstanceState)
searchView.setOnQueryTextListener(object : SearchView.OnQueryTextListener {
override fun onQueryTextSubmit(query: String): Boolean {
//filter the data in step 2
return false
}
override fun onQueryTextChange(query: String): Boolean {
orderHistoryViewModel.search(query)
return false
}
})
}
I have written setOnQueryTextListener in the Fragment. When I run the app, it is working only once. But how do I erase the filtered list and populate the original list everytime i clear the data from search bar and filter again when the new data is typed.
I wrote the search function in viewmodel. The below code filters data from the orinal list and populates the filtered list.
ViewModel.kt
fun search(query: String) {
var filteredList =
orderHistoryDetails?.orderList?.value?.filter { x -> x.order.contains(query) }
orderHistoryDetails?.orderList?.value = filteredList
}

You need to store original list also,and check whether query string is empty or not.
fun search(text: String) {
val filterList: MutableList<OrderItem> = arrayListOf()
if (text.trim().length == 0) {
filterList.clear()
filterList.addAll(listOriginal)
notifyDataSetChanged()
} else {
listOriginal.filter {x->
x.order.toUpperCase.contains(text)
}.apply {
filterList.clear()
filterList.addAll(this)
}
notifyDataSetChanged()
}
}