Develop Reference

Room livedata , databinding issue : UI doesn't update when data changes

I am now developing an application where I use MVVM pattern for UI and repository interaction. In other words, I receive live data object with a list of models from my ROOM data base query via repository, then assign it to my live data variable in viewmodel. After that, this data should be populated to my xml layout recycler view via data binding, but It happens only once fragment is initialised. In other cases recycler view is void
DAO code :
#Query("SELECT * FROM note WHERE content LIKE :query ORDER BY isStarred")
fun searchAllNotes(query : String?) : Flow<List<Note>>
ViewModel code:
#HiltViewModel
class HomeViewModel #Inject constructor (
private val noteRepository : NoteRepository
) : ViewModel() {
private var _notesLiveData : LiveData<List<Note>> = noteRepository.getAllNotes().asLiveData()
val notesLiveData get()= _notesLiveData
fun searchNotes(query : String){
viewModelScope.launch(Dispatchers.IO){
_notesLiveData = noteRepository.searchAllNotes(query).asLiveData()
}
}
fun deleteNote(note : Note){
viewModelScope.launch(Dispatchers.IO){
noteRepository.deleteNote(note)
}
}
fun updateNoteChecked(note : Note){
viewModelScope.launch(Dispatchers.IO){
noteRepository.updateNoteChecked(note.id, note.isStarred)
}
}
Fragment code
#AndroidEntryPoint
class HomeFragment : Fragment(),
NoteCardAdapter.NoteTouchListener,
SearchView.OnQueryTextListener{
private var _binding : FragmentHomeBinding? = null
val binding get() = _binding!!
private val adapter by lazy {
NoteCardAdapter(this as NoteCardAdapter.NoteTouchListener)
}
private val vm : HomeViewModel by viewModels()
private val noteSharedViewModel : NoteSharedViewModel by activityViewModels()
override fun onCreateView(
inflater: LayoutInflater, container: ViewGroup?,
savedInstanceState: Bundle?
): View {
_binding = FragmentHomeBinding.inflate(inflater)
return binding.root
}
override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
binding.adapter = adapter
binding.vm = vm
binding.apply {
lifecycleOwner = viewLifecycleOwner
homeRecyclerView.isNestedScrollingEnabled = false
homeRecyclerView.layoutManager = LinearLayoutManager(view.context)
homeRecyclerView.itemAnimator= NotesItemAnimator()
}
binding.homeSearchView.isSubmitButtonEnabled = true
binding.homeSearchView.setOnQueryTextListener(this as SearchView.OnQueryTextListener)
binding.addNoteButton.setOnClickListener{
val note = Note(
"","","",false, activity?.getDate(), folderId = -1
)
noteSharedViewModel.selectNote(note)
val action = HomeFragmentDirections.actionHomeFragmentToSingleNoteFragment(
isNew = true
)
findNavController().navigate(action)
}
binding.foldersButton.setOnClickListener{
findNavController().navigate(HomeFragmentDirections.actionHomeFragmentToFoldersFragment())
}
}
xml layout code :
<?xml version="1.0" encoding="utf-8"?>
<layout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
>
<data>
<variable
name="vm"
type="com.example.leonidsnotesapplication.presentation.notes_feature.viewmodels.HomeViewModel" />
<variable
name="adapter"
type="com.example.leonidsnotesapplication.presentation.notes_feature.adapters.NoteCardAdapter" />
</data>
<androidx.constraintlayout.widget.ConstraintLayout
android:background="#color/note_background_color_3"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".presentation.notes_feature.fragments.HomeFragment">
<androidx.appcompat.widget.SearchView
android:id="#+id/homeSearchView"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_margin="10dp"
android:theme="#style/AppSearchView"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintStart_toStartOf="parent"/>
<TextView
android:id="#+id/tvRecentTitle"
android:textStyle="bold"
android:textSize="25sp"
android:textColor="#color/button_color_2"
android:text="#string/recent"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginTop="20dp"
android:layout_marginStart="20dp"
app:layout_constraintTop_toBottomOf="#id/homeSearchView"
app:layout_constraintStart_toStartOf="parent"/>
<ImageView
android:layout_width="24dp"
android:layout_height="24dp"
android:layout_marginStart="16dp"
android:layout_marginTop="28dp"
android:background="#drawable/ic_circle_arrow"
app:layout_constraintStart_toEndOf="#id/tvRecentTitle"
app:layout_constraintTop_toBottomOf="#id/homeSearchView" />
<androidx.recyclerview.widget.RecyclerView
tools:listitem="#layout/note_card_view"
android:scrollbars="vertical"
android:scrollbarStyle="outsideInset"
android:id="#+id/homeRecyclerView"
android:layout_width="match_parent"
android:requiresFadingEdge="vertical"
android:fadingEdge="vertical"
android:fadingEdgeLength="15dp"
android:layout_height="500dp"
android:layout_marginTop="30dp"
app:setNoteAdapter="#{adapter}"
app:submitNoteList="#{vm.notesLiveData}"
app:layout_constraintTop_toBottomOf="#id/tvRecentTitle"
app:layout_constraintStart_toStartOf="parent"
/>
<com.google.android.material.floatingactionbutton.FloatingActionButton
android:backgroundTint="#color/button_color_1"
android:id="#+id/add_note_button"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_margin="16dp"
android:src="#drawable/ic_create"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent" />
<com.google.android.material.floatingactionbutton.FloatingActionButton
android:backgroundTint="#color/button_color_1"
android:id="#+id/folders_button"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_margin="16dp"
android:src="#drawable/ic_folders_stack"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintStart_toStartOf="parent" />
</androidx.constraintlayout.widget.ConstraintLayout>
</layout>
Data binding adapter :
#BindingAdapter("submitNoteList")
fun submitNoteList(recyclerView: RecyclerView, data : List<Note>?){
val adapter = recyclerView.adapter as NoteCardAdapter
adapter.setData((data as ArrayList<Note>? ?: arrayListOf()))
}
#BindingAdapter("setNoteAdapter")
fun setNoteAdapter(recyclerView: RecyclerView, adapter: NoteCardAdapter){
adapter.let {
recyclerView.adapter = it
}
}

You should observe your live data. Example code is:
vm.notesLiveData.observe(viewLifecycleOwner) { adapter.submitList(it) }

Bind viewmodel to recyclerview item.xml with databinding, android?

I want to bind data on adapter from viewmodel in xml layout file
This is my fragment class.
class NotificationFragment : Fragment() {
var customeProgressDialog: CustomeProgressDialog? = null
private val appPreferences: AppPreference by inject()
private val notificationViewModel: NotificationViewModel by viewModel()
private lateinit var binding: FragmentNotificationBinding
override fun onCreateView(
inflater: LayoutInflater, container: ViewGroup?,
savedInstanceState: Bundle?
): View? {
binding = FragmentNotificationBinding.inflate(inflater, container, false)
return binding.getRoot()
}
override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
super.onViewCreated(view, savedInstanceState)
binding.notification.layoutManager=LinearLayoutManager(activity, LinearLayoutManager.VERTICAL, false)
customeProgressDialog = CustomeProgressDialog(activity)
notificationViewModel.notifications(
appPreferences.getUsername(),
appPreferences.getPassword(),
appPreferences.getUserId()
)
initObservables()
}
private fun initObservables() {
notificationViewModel.progressDialog?.observe(this, Observer {
if (it!!) customeProgressDialog?.show() else customeProgressDialog?.dismiss()
})
notificationViewModel.apiResponse?.observe(
viewLifecycleOwner,
androidx.lifecycle.Observer { response ->
if (response.dataList != null) {
var notificationAdapter = NotificationAdapter(response.dataList as List<Data>)
notificationAdapter.notifyDataSetChanged()
binding.notification.adapter = notificationAdapter
}
})
}
}
My viewmodel
class NotificationViewModel(networkCall: NetworkCall) : ViewModel(),
Callback<ApiResponse> {
var progressDialog: SingleLiveEvent<Boolean>? = null
var apiResponse: MutableLiveData<ApiResponse>? = null
var networkCall: NetworkCall;
init {
progressDialog = SingleLiveEvent<Boolean>()
apiResponse = MutableLiveData<ApiResponse>()
this.networkCall = networkCall
}
fun notifications(username: String?, password: String?, userId: String?) {
progressDialog?.value = true
val apiPost = ApiPost()
apiPost.userName = username
apiPost.password = password
apiPost.UserId = userId
apiPost.FileType = NetworkConstant.FILE_TYPE_NOT
networkCall.getPDF(apiPost).enqueue(this)
}
override fun onFailure(call: Call<ApiResponse>, t: Throwable) {
progressDialog?.value = false
}
override fun onResponse(call: Call<ApiResponse>, response: Response<ApiResponse>) {
progressDialog?.value = false
apiResponse?.value = response.body()
}
}
The adapter class
lass NotificationAdapter(private val list: List<Data>) :
RecyclerView.Adapter<NotificationAdapter.ViewHolder>() {
override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): ViewHolder {
val inflater = LayoutInflater.from(parent.context)
val view = inflater.inflate(R.layout.element_list, parent, false)
return ViewHolder(view)
}
override fun onBindViewHolder(holder: ViewHolder, position: Int) {
val movie: Data = list[position]
holder.bind(movie)
holder.itemView.setOnClickListener {
if (!TextUtils.isEmpty(movie.filePath)) {
try {
val browserIntent = Intent(Intent.ACTION_VIEW, Uri.parse(movie.filePath))
holder.itemView.context.startActivity(browserIntent)
} catch (e: Exception) {
e.printStackTrace()
}
}
}
}
override fun getItemCount(): Int = list.size
inner class ViewHolder(itemView: View) : RecyclerView.ViewHolder(itemView) {
fun bind(movie: Data) {
with(itemView) {
tv_notifi.text = movie.displayName
tv_date.text = movie.UpdatedDate
if (movie.description != null) {
tv_brief.text = movie.description
tv_brief.visibility = View.VISIBLE
}
}
}
}
}
This is my item xml layout
<layout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto">
<data>
<variable
name="viewmodel"
type="com.mountmeru.viewmodel.NotificationViewModel" />
</data>
<androidx.cardview.widget.CardView
android:id="#+id/main_cardview"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginBottom="5dp">
<androidx.appcompat.widget.LinearLayoutCompat
android:id="#+id/main_cardrl"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="horizontal">
<RelativeLayout
android:id="#+id/rl_newsdate"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_weight="0.3">
<androidx.appcompat.widget.AppCompatTextView
android:id="#+id/tv_notifi"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginLeft="10dp"
android:layout_marginTop="10dp"
android:layout_marginRight="10dp"
android:maxLines="2"
android:text="hey i am notification text"
android:textColor="#android:color/black"
android:textSize="16sp" />
<androidx.appcompat.widget.AppCompatTextView
android:id="#+id/tv_brief"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_below="#+id/tv_notifi"
android:layout_marginLeft="10dp"
android:layout_marginTop="5dp"
android:layout_marginRight="10dp"
android:textColor="#android:color/black"
android:textSize="16sp"
android:visibility="gone" />
<androidx.appcompat.widget.AppCompatTextView
android:id="#+id/tv_date"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_below="#+id/tv_brief"
android:layout_marginLeft="10dp"
android:layout_marginTop="2dp"
android:layout_marginRight="10dp"
android:maxLines="1"
android:text="hey i am date"
android:textColor="#color/inactive_text"
android:textSize="14sp" />
</RelativeLayout>
<RelativeLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_toRightOf="#+id/rl_newsdate"
android:layout_weight="0.7"
android:padding="5dp">
<androidx.appcompat.widget.AppCompatImageView
android:id="#+id/iv_notifi"
android:layout_width="match_parent"
android:layout_height="75dp"
android:layout_centerHorizontal="true"
android:layout_centerVertical="true"
android:src="#drawable/mer" />
</RelativeLayout>
</androidx.appcompat.widget.LinearLayoutCompat>
</androidx.cardview.widget.CardView>
</layout>
I was able to do the binding for the fragment but for adapter I am unsure how to proceed.

If I understand your question correctly, you want to pass data to your adapter inside xml. For this, you will need to write custom binding adapter for your RecyclerView.
This link has all you need.
https://android.jlelse.eu/how-to-bind-a-list-of-items-to-a-recyclerview-with-android-data-binding-1bd08b4796b4

How can a ViewModel function access the Place instance returned by PlaceSelectionListener of AutocompleteSupportFragment?

I am building an Android app using Kotlin.
I have a layout that contains a create_button. When the user clicks the button, the onClick should call onCreateJourney() in my ViewModel. This function requires the selectedPlaceId parameter to update a Journey entity with its value.
In my Fragment, I use the AutocompleteSupportFragment for the user to search and choose the desired place. This works well, as onPlaceSelected() returns the correct place in response to the user's selection. But I can't figure out how to use the returned place id value (p0.id) in my ViewModel onCreateJourney().
At this stage, the compiler throws this error:
cannot find method onCreateJourney() in class com.example.traveljournal.journey.NewJourneyViewModel
Please, can you shed some light on this issue for me?
My UI (.xml fragment layout):
<?xml version="1.0" encoding="utf-8"?>
<layout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
tools:context=".journey.NewJourneyFragment">
<data>
<variable
name="newJourneyViewModel"
type="com.example.traveljournal.journey.NewJourneyViewModel" />
</data>
<androidx.constraintlayout.widget.ConstraintLayout
android:layout_width="match_parent"
android:layout_height="match_parent">
<TextView
android:id="#+id/whereQuestion"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginStart="10dp"
android:layout_marginTop="20dp"
android:layout_marginEnd="10dp"
android:text="#string/whereQuestion"
android:textSize="18sp"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.027"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#+id/journeyBckgImageView" />
<androidx.cardview.widget.CardView
android:id="#+id/cardView"
android:layout_width="match_parent"
android:layout_height="wrap_content"
app:layout_constraintBottom_toBottomOf="parent">
</androidx.cardview.widget.CardView>
<fragment
android:id="#+id/autocomplete_fragment"
android:name="com.google.android.libraries.places.widget.AutocompleteSupportFragment"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginStart="10dp"
android:layout_marginTop="10dp"
android:layout_marginEnd="10dp"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#+id/whereQuestion" />
<Button
android:id="#+id/create_button"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginBottom="16dp"
android:onClick="#{() -> newJourneyViewModel.onCreateJourney()}"
android:text="#string/createJourneyButton"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent" />
</androidx.constraintlayout.widget.ConstraintLayout>
</layout>
My ViewModel
class NewJourneyViewModel (
private val journeyKey: Long = 0L,
val database: TravelDatabaseDao) : ViewModel() {
private var viewModelJob = Job()
private val uiScope = CoroutineScope(Dispatchers.Main + viewModelJob)
private val _navigateToJourneys = MutableLiveData<Boolean?>()
val navigateToJourneys: LiveData<Boolean?>
get() = _navigateToJourneys
fun doneNavigating() {
_navigateToJourneys.value = null
}
fun onCreateJourney(selectedPlaceId: String) {
uiScope.launch {
withContext(Dispatchers.IO) {
val journey = database.getJourney(journeyKey) ?: return#withContext
journey.placeId = selectedPlaceId
database.updateJourney(journey)
}
_navigateToJourneys.value = true
}
}
override fun onCleared() {
super.onCleared()
viewModelJob.cancel()
}
}
My Fragment
class NewJourneyFragment : Fragment(), PlaceSelectionListener {
override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?): View? {
(activity as AppCompatActivity).supportActionBar?.title = getString(R.string.createJourney)
val binding: FragmentNewJourneyBinding = DataBindingUtil.inflate(
inflater,
R.layout.fragment_new_journey, container, false
)
val application = requireNotNull(this.activity).application
val arguments = NewJourneyFragmentArgs.fromBundle(arguments!!)
val dataSource = TravelDatabase.getInstance(application).travelDatabaseDao
val viewModelFactory = NewJourneyViewModelFactory(arguments.journeyKey, dataSource)
val newJourneyViewModel =
ViewModelProviders.of(
this, viewModelFactory).get(NewJourneyViewModel::class.java)
binding.newJourneyViewModel = newJourneyViewModel
newJourneyViewModel.navigateToJourneys.observe(this, Observer {
if(it == true) {
this.findNavController().navigate(
NewJourneyFragmentDirections.actionNewJourneyDestinationToJourneysDestination())
newJourneyViewModel.doneNavigating()
}
})
if (!Places.isInitialized()) {
this.context?.let { Places.initialize(it, getString(R.string.apiKey), Locale.US) }
}
val autocompleteFragment = childFragmentManager.findFragmentById(R.id.autocomplete_fragment)
as? AutocompleteSupportFragment
autocompleteFragment?.setOnPlaceSelectedListener(this)
autocompleteFragment!!.setHint(getString(R.string.destinationExample))
autocompleteFragment!!.setPlaceFields(Arrays.asList(Place.Field.ID, Place.Field.NAME))
return binding.root
}
#ExperimentalStdlibApi
override fun onPlaceSelected(p0: Place) {
Log.i("PLACE", "Place: " + p0.name + ", " + p0.id)
}
override fun onError(status: Status) {
Toast.makeText(this.context,""+status.toString(),Toast.LENGTH_LONG).show()
Log.i("ERROR", "An error occurred: " + status)
}
}

You have to pass the field selectedPlaceId as an argument in the xml :
android:onClick="#{() -> newJourneyViewModel.onCreateJourney(newJourneyViewModel.selectedPlaceId)}"
How will you get the selectedPlaceId in view model depends on your programming logic.
For testing purposes, you can hardcode the value.

In NewJourneyViewModel, I set up selectedPlaceId as MutableLiveData.
val selectedPlaceId = MutableLiveData<String>()
In NewJourneyFragment, I used lateinit to create a field for NewJourneyViewModel called newJourneyViewModel and initialized it in onCreateView().
private lateinit var newJourneyViewModel : NewJourneyViewModel
Now having access to my ViewModel outside of onCreateView(), in my Fragment onPlaceSelected() method I can set the value of selectedPlaceId to p0.id.
newJourneyViewModel.selectedPlaceId.value = p0.id
If anybody can come up with a better and safer approach on this, it will be highly appreciated.

Recyclerview Item onclick overlays the next fragment instead of replacing it

I have these activity, fragments, its viewmodels, and their adapter. I can already call the next fragment on click of a recyclerview item, but the new fragment overlays on the first fragment.
Refer to screenshot below:
Next screenshot is the old fragment view:
As for the mainactivity:
class MainActivity : AppCompatActivity(), RecyclerViewClickListener {
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
val navView: BottomNavigationView = findViewById(R.id.nav_view)
val navController = findNavController(R.id.nav_host_fragment)
// Passing each menu ID as a set of Ids because each
// menu should be considered as top level destinations.
val appBarConfiguration = AppBarConfiguration(
setOf(
R.id.navigation_home,
R.id.navigation_messages,
R.id.navigation_notifications,
R.id.navigation_account
)
)
setupActionBarWithNavController(navController, appBarConfiguration)
navView.setupWithNavController(navController)
if (savedInstanceState == null) {
supportFragmentManager
.beginTransaction()
.add(R.id.fragment_home, HomeFragment.newInstance(), "dormList")
.commit()
}
}
override fun onRecyclerViewItemClick(view: View, dorms: Dorms) {
val detailsFragment = dormDetailsFragment.newInstance(dorms)
supportFragmentManager
.beginTransaction()
.replace(R.id.fragment_home, detailsFragment, "Dorm Details")
.addToBackStack(null)
.commit()
}
}
HomeFragment:
class HomeFragment : Fragment(), RecyclerViewClickListener {
private lateinit var factory: HomeViewModelFactory
private lateinit var viewModel: HomeViewModel
private var callback : RecyclerViewClickListener? = null
companion object {
fun newInstance(): HomeFragment {
return HomeFragment()
}
}
override fun onAttach(context: Context) {
super.onAttach(context)
if(context is RecyclerViewClickListener) callback = context
else throw ClassCastException("$context must implement Callback")
}
override fun onDetach() {
super.onDetach()
callback = null
}
override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?): View? {
return inflater.inflate(R.layout.fragment_home, container, false)
}
override fun onActivityCreated(savedInstanceState: Bundle?) {
super.onActivityCreated(savedInstanceState)
val api = DormsAPI()
val repository = DormRepository(api)
factory = HomeViewModelFactory(repository)
viewModel = ViewModelProviders.of(this, factory).get(HomeViewModel::class.java)
viewModel.getDorms()
viewModel.dorms.observe(viewLifecycleOwner, Observer { dorms ->
recyclerViewDorms.also{
it.layoutManager = LinearLayoutManager(requireContext())
it.setHasFixedSize(true)
it.adapter = dormAdapter(dorms, this)
}
})
}
override fun onRecyclerViewItemClick(view: View, dorms: Dorms) {
when(view.id){
R.id.button_reserve -> {
// TODO: Go to new account if not signed up, etc...
Toast.makeText(requireContext(), "Reserve button clicked", Toast.LENGTH_LONG).show()
}
R.id.layoutBox -> {
// TODO: Go to Dorm Details
callback?.onRecyclerViewItemClick(view, dorms)
}
}
}
}
Home View Model
class HomeViewModel(private val repository: DormRepository) : ViewModel() {
private lateinit var job: Job
private val _dorms = MutableLiveData<List<Dorms>>()
val dorms: LiveData<List<Dorms>>
get() = _dorms
fun getDorms() {
job = Coroutines.ioThenMain(
{ repository.getDorms() },
{ _dorms.value = it }
)
}
override fun onCleared() {
super.onCleared()
if(::job.isInitialized) job.cancel()
}
}
Interface:
interface RecyclerViewClickListener {
fun onRecyclerViewItemClick(view: View, dorms: Dorms)
}
Details Fragment:
class dormDetailsFragment : Fragment() {
companion object {
private const val DORMS = "model"
fun newInstance(dorms: Dorms): dormDetailsFragment{
val args = Bundle()
args.putSerializable(DORMS, dorms)
val fragment = dormDetailsFragment()
fragment.arguments = args
return fragment
}
}
private lateinit var viewModel: DormDetailsViewModel
override fun onCreateView(
inflater: LayoutInflater, container: ViewGroup?,
savedInstanceState: Bundle?
): View? {
val fragmentDormDetailsBinding =
FragmentDormDetailsBinding.inflate(inflater,container,false)
val model = arguments!!.getSerializable(DORMS) as Dorms
fragmentDormDetailsBinding.dormDetails = model
return fragmentDormDetailsBinding.root
}
}
Home Fragment Layout
<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:id="#+id/fragment_home">
<TextView
android:id="#+id/text_home"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginStart="8dp"
android:layout_marginTop="8dp"
android:layout_marginEnd="8dp"
android:textAlignment="center"
android:textSize="20sp"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
<androidx.swiperefreshlayout.widget.SwipeRefreshLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:id="#+id/refreshLayout">
<androidx.recyclerview.widget.RecyclerView
tools:listitem="#layout/layout_home"
android:id="#+id/recyclerViewDorms"
android:layout_width="0dp"
android:layout_height="0dp"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintLeft_toLeftOf="parent"
app:layout_constraintRight_toRightOf="parent"
app:layout_constraintBottom_toBottomOf="parent" />
</androidx.swiperefreshlayout.widget.SwipeRefreshLayout>
</androidx.constraintlayout.widget.ConstraintLayout>
Details Layout
<?xml version="1.0" encoding="utf-8"?>
<layout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools">
<data>
<import type="android.view.View" />
<variable
name="dormDetails"
type="com.pptt.roomy.data.models.Dorms" />
</data>
<androidx.constraintlayout.widget.ConstraintLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context="com.pptt.roomy.ui.home.dormDetails.DormDetailsFragment"
android:id="#+id/DormDetailsFrag">
<ImageView
app:image="#{dormDetails.image}"
android:id="#+id/image"
android:layout_width="match_parent"
android:layout_height="0dp"
app:layout_constraintDimensionRatio="1:1"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintLeft_toLeftOf="parent"
app:layout_constraintRight_toRightOf="parent"
android:background="#drawable/propertysample"
/>
<TextView
android:text="#{String.valueOf(dormDetails.dormPrice)}"
tools:text="Php 2500"
android:id="#+id/textViewPrice"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:paddingTop="6dp"
android:layout_marginStart="10dp"
android:textSize="20sp"
android:textStyle="normal"
android:textColor="#000000"
app:layout_constraintTop_toBottomOf="#id/image"
app:layout_constraintLeft_toLeftOf="parent" />
<TextView
android:text="#{dormDetails.dormName}"
tools:text="Dorm ni Jupa"
android:id="#+id/textViewPropertyName"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:paddingTop="1dp"
android:layout_marginStart="10dp"
android:textSize="24sp"
android:textStyle="bold"
android:textColor="#000000"
app:layout_constraintTop_toBottomOf="#id/textViewPrice"
app:layout_constraintLeft_toLeftOf="parent" />
<TextView
android:text="#{dormDetails.dormType}"
tools:text="1 BR with Dining and Kitchen"
android:id="#+id/textViewRoomType"
android:layout_below="#id/textViewPropertyName"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:paddingTop="5dp"
android:layout_marginLeft="40dp"
android:textSize="16sp"
app:layout_constraintTop_toBottomOf="#+id/textViewPropertyName"
app:layout_constraintLeft_toLeftOf="parent"/>
<TextView
android:text="#{dormDetails.dormAddress}"
android:id="#+id/textViewAddress"
android:layout_marginBottom="5dp"
tools:text="455 San Jose II St., Brgy. 425, Sampaloc, Manila"
android:textAppearance="#style/Base.TextAppearance.AppCompat.Small"
android:padding="5dp"
android:layout_marginLeft="40dp"
android:layout_width="wrap_content"
android:textAlignment="center"
android:layout_height="wrap_content"
app:layout_constraintTop_toBottomOf="#+id/textViewRoomType"
app:layout_constraintLeft_toLeftOf="parent"/>
<TextView
android:text="#{dormDetails.dormDetails}"
android:id="#+id/textViewDescription"
android:layout_width="match_parent"
android:layout_height="wrap_content"
tools:text="A very long textarea to contain dorm description. Should be multiline"
android:padding="5dp"
android:layout_marginLeft="20dp"
app:layout_constraintTop_toBottomOf="#id/textViewAddress"
app:layout_constraintLeft_toLeftOf="parent"/>
</androidx.constraintlayout.widget.ConstraintLayout>
</layout>
Anything else that's needed will be edited for later.

Remove these lines:
if (savedInstanceState == null) {
supportFragmentManager
.beginTransaction()
.add(R.id.fragment_home, HomeFragment.newInstance(), "dormList")
.commit()
}
You're adding one HomeFragment via the NavHostFragment and another manually. You don't need to manually add Fragment when using Navigation.
You should also be updating your onRecyclerViewItemClick to use navigate() as per the Navigate to a destination documentation:
override fun onRecyclerViewItemClick(view: View, dorms: Dorms) {
val navController = findNavController(R.id.nav_host_fragment)
// If you're using Safe Args, use the ID generated from
// the navigation graph and make sure you have
// an argument of the correct type
navController.navigate(
HomeFragmentDirections.actionHomeToDetails(dorms))
}
You might find it helpful to look at the Pass data between destinations documentation to see how to create an <argument> in your graph for your Dorms object and how to set up Safe Args to generate the Directions class for you.

Why isn't 'onPropertyChanged' being called?

I'm writing an application with 2-way data binding. I can get the edit text field to update, but I'm also trying to update internal logic too. I've tried to do this by calling addOnPropertyChangedCallback(Observable.OnPropertyChangedCallback) on the binding, however despite checking notifyPropertyChanged(int) is being called by the observable, the callback isn't being called
I've tried adding the #Bindable annotation to both the getter and the setter as mentioned in this stackoverflow question but to no avail.
AddItemObservable.kt
class AddItemObservable : BaseObservable(), AddItemImmutableObservable {
private var name = ""
private var quantity: Int? = null
#Bindable
override fun getName() = name
fun setName(name: String) {
if (this.name == name) {
return
}
this.name = name
notifyPropertyChanged(BR.name)
}
#Bindable
override fun getQuantity() = quantity
fun setQuantity(quantity: Int?) {
if (this.quantity?.equals(quantity) == true) {
return
}
this.quantity = quantity
notifyPropertyChanged(BR.quantity)
}
}
AndroidView.kt
class AndroidView : Fragment() {
private lateinit var binding: FragmentAddItemBinding
override fun onCreateView(
inflater: LayoutInflater, container: ViewGroup?,
savedInstanceState: Bundle?
): View? {
binding = FragmentAddItemBinding.inflate(inflater, container, false)
binding.addItem = AddItemObservable()
binding.addOnPropertyChangedCallback(object : Observable.OnPropertyChangedCallback() {
override fun onPropertyChanged(sender: Observable?, propertyId: Int) {
Log.i("VIEW", "updated")
}
})
binding.lifecycleOwner = this
return binding.root
}
}
fragment_add_item.xml
<?xml version="1.0" encoding="utf-8"?>
<layout>
<data>
<import type="tk.jonathancowling.inventorytracker.additem.AddItemObservable" />
<variable
name="addItem"
type="AddItemObservable" />
</data>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<EditText
android:id="#+id/editText"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginStart="8dp"
android:layout_marginTop="8dp"
android:layout_marginEnd="8dp"
android:ems="10"
android:hint="#string/add_item_name"
android:inputType="textPersonName"
android:text="#={addItem.name}"
android:importantForAutofill="no"
tools:ignore="UnusedAttribute" />
<EditText
android:id="#+id/editText2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginStart="8dp"
android:layout_marginTop="8dp"
android:layout_marginEnd="8dp"
android:ems="10"
android:hint="#string/add_item_quantity"
android:inputType="number"
app:add_item_quantity="#={addItem.quantity}"
android:importantForAutofill="no"
tools:ignore="UnusedAttribute" />
</LinearLayout>
</layout>
Adapters omitted for brevity
I expect the OnPropertyChangedCallback to be called and log "updated" when notifyPropertyChanged is called (which happens when text is entered into one of the EditText).

To make it work, you need call addOnPropertyChangedCallback directly on Observable instance. For example,
val observableItem = AddItemObservable()
binding.addItem = observableItem
observableItem.addOnPropertyChangedCallback(object : Observable.OnPropertyChangedCallback() {
override fun onPropertyChanged(sender: Observable?, propertyId: Int) {
Log.i("VIEW", "updated")
}
})