I am trying to display data from IconFinder API. It seems to be ItemKeyedDataSource for me and I used Paging3 to display the data as it's mentioned in the official docs.
Here is code, please check if there're any issues with the implementation I have done and where is the mistake.
IconSetsRemoteMediator
#OptIn(ExperimentalPagingApi::class)
class IconSetsRemoteMediator(
private val query: String?,
private val database: IconsFinderDatabase,
private val networkService: IconFinderAPIService
) : RemoteMediator<Int, IconSetsEntry>() {
private val TAG: String? = IconSetsRemoteMediator::class.simpleName
private val iconSetsDao = database.iconSetsDao
private val remoteKeysDao = database.remoteKeysDao
override suspend fun initialize(): InitializeAction {
// Load fresh data when ever the app is open new
return InitializeAction.LAUNCH_INITIAL_REFRESH
}
override suspend fun load(
loadType: LoadType,
state: PagingState<Int, IconSetsEntry>
): MediatorResult {
val iconSetID = when (loadType) {
LoadType.REFRESH -> {
null
}
LoadType.PREPEND -> {
return MediatorResult.Success(
endOfPaginationReached = true
)
}
LoadType.APPEND -> {
Log.d(TAG, "LoadType.APPEND")
val lastItem = state.lastItemOrNull()
if (lastItem == null) {
return MediatorResult.Success(
endOfPaginationReached = true
)
}
// Get the last item from the icon-sets list and return its ID
lastItem.iconset_id
}
}
try {
// Suspending network load via Retrofit.
val response = networkService.getAllPublicIconSets(after = iconSetID)
val iconSets = response.iconsets
val endOfPaginationReached = iconSets == null || iconSets.isEmpty()
database.withTransaction {
if (loadType == LoadType.REFRESH) {
// Delete the data in the database
iconSetsDao.deleteAllIconSets()
//remoteKeysDao.deleteRemoteKeys()
}
Log.d(TAG, "iconSets = ${iconSets?.size}")
Log.d(TAG, "endOfPaginationReached = $endOfPaginationReached")
Log.d(TAG, "state.anchorPosition = ${state.anchorPosition}")
Log.d(TAG, "state.pages = ${state.pages.size}")
val time = System.currentTimeMillis()
/*val remoteKeys = iconSets!!.map {
RemoteKeysEntry(it.iconset_id, time)
}*/
// Insert new IconSets data into database, which invalidates the current PagingData,
// allowing Paging to present the updates in the DB.
val data = iconSets!!.mapAsIconSetsEntry()
iconSetsDao.insertAllIconSets(data)
// Insert the remote key values which set the time at which the data is
// getting updated in the DB
//remoteKeysDao.insertRemoteKeys(remoteKeys)
}
return MediatorResult.Success(endOfPaginationReached = endOfPaginationReached)
} catch (exception: IOException) {
return MediatorResult.Error(exception)
} catch (exception: HttpException) {
return MediatorResult.Error(exception)
}
}
}
IconFinderRepository
class IconFinderRepository(
private val service: IconFinderAPIService,
private val database: IconsFinderDatabase
) {
private val TAG: String? = IconFinderRepository::class.simpleName
fun getPublicIconSets(): Flow<PagingData<IconSetsEntry>> {
Log.d(TAG, "New Icon Sets query")
val pagingSourceFactory = { database.iconSetsDao.getIconSets() }
#OptIn(ExperimentalPagingApi::class)
return Pager(
config = PagingConfig(pageSize = NUMBER_OF_ITEMS_TO_FETCH, enablePlaceholders = false),
remoteMediator = IconSetsRemoteMediator(
query = null,
database,
service
),
pagingSourceFactory = pagingSourceFactory
).flow
}
companion object {
const val NUMBER_OF_ITEMS_TO_FETCH = 20
}
}
IconSetViewHolder
class IconSetViewHolder private constructor(val binding: RecyclerItemIconSetBinding) :
RecyclerView.ViewHolder(binding.root) {
fun bind(iconSetsEntry: IconSetsEntry?) {
if (iconSetsEntry == null) {
//Show the Loading UI
} else {
binding.model = iconSetsEntry
binding.executePendingBindings()
}
}
companion object {
fun from(parent: ViewGroup): IconSetViewHolder {
val layoutInflater = LayoutInflater.from(parent.context)
val binding = RecyclerItemIconSetBinding.inflate(layoutInflater, parent, false)
return IconSetViewHolder(binding)
}
}
}
IconSetAdapter
class IconSetAdapter : PagingDataAdapter<UiModel.IconSetDataItem, ViewHolder>(UI_MODEL_COMPARATOR) {
companion object {
private val UI_MODEL_COMPARATOR =
object : DiffUtil.ItemCallback<UiModel.IconSetDataItem>() {
override fun areContentsTheSame(
oldItem: UiModel.IconSetDataItem,
newItem: UiModel.IconSetDataItem
): Boolean {
return oldItem.iconSetsEntry.iconset_id == newItem.iconSetsEntry.iconset_id
}
override fun areItemsTheSame(
oldItem: UiModel.IconSetDataItem,
newItem: UiModel.IconSetDataItem
): Boolean =
oldItem == newItem
}
}
override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): ViewHolder {
return if (viewType == R.layout.recycler_item_icon_set) {
IconSetViewHolder.from(parent)
} else {
IconSetViewHolder.from(parent)
}
}
override fun getItemViewType(position: Int): Int {
return when (getItem(position)) {
is UiModel.IconSetDataItem -> R.layout.recycler_item_icon_set
null -> throw UnsupportedOperationException("Unknown view")
else -> throw UnsupportedOperationException("Unknown view")
}
}
override fun onBindViewHolder(holder: ViewHolder, position: Int) {
val uiModel = getItem(position)
uiModel.let {
when (uiModel) {
is UiModel.IconSetDataItem -> (holder as IconSetViewHolder).bind(uiModel.iconSetsEntry)
}
}
}
}
HomeFragmentViewModel
class HomeFragmentViewModel(application: Application) : AndroidViewModel(application) {
private val TAG: String? = HomeFragmentViewModel::class.simpleName
private val repository: IconFinderRepository = IconFinderRepository(
IconFinderAPIService.create(),
IconsFinderDatabase.getInstance(application)
)
private var iconSetsQueryResult: Flow<PagingData<UiModel.IconSetDataItem>>? = null
fun iconSetsQuery(): Flow<PagingData<UiModel.IconSetDataItem>> {
val newResult: Flow<PagingData<UiModel.IconSetDataItem>> = repository.getPublicIconSets()
.map { pagingData -> pagingData.map { UiModel.IconSetDataItem(it) } }
.cachedIn(viewModelScope)
iconSetsQueryResult = newResult
return newResult
}
/**
* Factory for constructing HomeFragmentViewModel
*/
class Factory(private val application: Application) : ViewModelProvider.Factory {
override fun <T : ViewModel?> create(modelClass: Class<T>): T {
if (modelClass.isAssignableFrom(HomeFragmentViewModel::class.java)) {
return HomeFragmentViewModel(application) as T
}
throw IllegalArgumentException("Unable to construct ViewModel")
}
}
}
sealed class UiModel {
data class IconSetDataItem(val iconSetsEntry: IconSetsEntry) : UiModel()
}
IconSetFragment: This is one of the fragments implemented as part of ViewPager. Its parent is a Fragment in an Activity.
class IconSetFragment : Fragment() {
private val TAG: String = IconSetFragment::class.java.simpleName
/**
* Declaring the UI Components
*/
private lateinit var binding: FragmentIconSetBinding
private val viewModel: HomeFragmentViewModel by viewModels()
private val adapter = IconSetAdapter()
private var job: Job? = null
companion object {
fun newInstance(): IconSetFragment {
return IconSetFragment()
}
}
override fun onCreateView(
inflater: LayoutInflater,
container: ViewGroup?,
savedInstanceState: Bundle?
): View? {
// Get a reference to the binding object
binding = DataBindingUtil.inflate(inflater, R.layout.fragment_icon_set, container, false)
Log.d(TAG, "onCreateView")
return binding.root
}
override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
super.onViewCreated(view, savedInstanceState)
initAdapter()
job?.cancel()
job = viewLifecycleOwner.lifecycleScope.launch {
viewModel.iconSetsQuery().collectLatest {
adapter.submitData(it)
Log.d(TAG, "collectLatest $it")
}
}
}
private fun initAdapter() {
binding.rvIconSetList.adapter = adapter
/*.withLoadStateHeaderAndFooter(
header = LoadStateAdapter(), // { adapter.retry() },
footer = LoadStateAdapter { adapter.retry() }
)*/
}
}
IconSetsDao
#Dao
interface IconSetsDao {
#Insert(onConflict = OnConflictStrategy.REPLACE)
suspend fun insertAllIconSets(iconSets: List<IconSetsEntry>)
#Query("SELECT * FROM icon_sets_table")
fun getIconSets(): PagingSource<Int, IconSetsEntry>
#Query("DELETE FROM icon_sets_table")
suspend fun deleteAllIconSets()
}
This is the Logcat screenshot, the load() method is being invoked without any scrolling action.
I have the similar issue, seems the recursive loading issue is fixed by setting the recyclerView.setHasFixedSize(true)
Related
I'm learning paging 3, but the data from the API doesn't appear. My code is like below:
interface PokeAPI {
#GET("pokemon")
fun getPokemonList() : Call<PokemonList>
#GET("pokemon")
fun getAllPokemon(
#Query("limit") limit: Int,
#Query("offset") offset: Int) : PokemonList
#GET("pokemon/{name}")
fun getPokemonInfo(
#Path("name") name: String
) : Call<Pokemon>
}
class PokePagingSource(private val apiService: PokeAPI): PagingSource<Int, Result>() {
private companion object {
const val INITIAL_PAGE_INDEX = 1
}
override suspend fun load(params: LoadParams<Int>): LoadResult<Int, Result> {
return try {
val position = params.key ?: INITIAL_PAGE_INDEX
val responseData = apiService.getAllPokemon(position, params.loadSize)
if (responseData.results.isEmpty()) {
Log.e("Response Succeed!", responseData.results.toString())
} else {
Log.e("Response Failed!", responseData.results.toString())
}
LoadResult.Page(
data = responseData.results,
prevKey = if (position == INITIAL_PAGE_INDEX) null else position - 1,
nextKey = if (responseData.results.isNullOrEmpty()) null else position + 1
)
} catch (exception: Exception) {
return LoadResult.Error(exception)
}
}
override fun getRefreshKey(state: PagingState<Int, Result>): Int? {
return state.anchorPosition?.let { anchorPosition ->
val anchorPage = state.closestPageToPosition(anchorPosition)
anchorPage?.prevKey?.plus(1) ?: anchorPage?.nextKey?.minus(1)
}
}
}
class PokemonRepository(private val apiService: PokeAPI) {
fun getAllPokemon(): LiveData<PagingData<Result>>{
return Pager(
config = PagingConfig(
pageSize = 10
),
pagingSourceFactory = {
PokePagingSource(apiService)
}
).liveData
}
}
object Injection {
private val api by lazy { RetrofitClient().endpoint }
fun provideRepository(): PokemonRepository {
return PokemonRepository(api)
}
}
class PokemonViewModel(pokemonRepository: PokemonRepository) : ViewModel() {
val allPokemonList: LiveData<PagingData<Result>> =
pokemonRepository.getAllPokemon().cachedIn(viewModelScope)
}
class ViewModelFactory : ViewModelProvider.Factory {
override fun <T : ViewModel> create(modelClass: Class<T>): T {
if (modelClass.isAssignableFrom(PokemonViewModel::class.java)) {
#Suppress("UNCHECKED_CAST")
return PokemonViewModel(Injection.provideRepository()) as T
}
throw IllegalArgumentException("Unknown ViewModel class")
}
}
`class PokemonPagingAdapter(private val context: Context) :
PagingDataAdapter<Result, PokemonPagingAdapter.ViewHolder>(DIFF_CALLBACK) {
private var onItemClick: OnAdapterListener? = null
fun setOnItemClick(onItemClick: OnAdapterListener) {
this.onItemClick = onItemClick
}
class ViewHolder(val binding: AdapterPokemonBinding) : RecyclerView.ViewHolder(binding.root) {
}
override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): ViewHolder {
return ViewHolder(
AdapterPokemonBinding.inflate(
LayoutInflater.from(parent.context),
parent,
false
)
)
}
override fun onBindViewHolder(holder: ViewHolder, position: Int) {
val pokemonData = getItem(position)
if (pokemonData != null) {
holder.binding.apply {
val number = if (pokemonData.url.endsWith("/")) {
pokemonData.url.dropLast(1).takeLastWhile { it.isDigit() }
} else {
pokemonData.url.takeLastWhile { it.isDigit() }
}
val url = "https://raw.githubusercontent.com/PokeAPI/sprites/master/sprites/pokemon/${number}.png"
Glide.with(context)
.load(url)
.transition(DrawableTransitionOptions.withCrossFade())
.centerCrop()
.circleCrop()
.into(ivPokemon)
tvNamePokemon.text = pokemonData.name
btnDetail.setOnClickListener {
onItemClick?.onClick(pokemonData, pokemonData.name, url)
}
}
}
}
companion object {
val DIFF_CALLBACK = object : DiffUtil.ItemCallback<Result>() {
override fun areItemsTheSame(
oldItem: Result,
newItem: Result
): Boolean {
return oldItem == newItem
}
override fun areContentsTheSame(
oldItem: Result,
newItem: Result
): Boolean {
return oldItem.name == newItem.name
}
}
}
interface OnAdapterListener {
fun onClick(data: Result, name: String, url: String)
}
}`
class FragmentPokemon: Fragment(R.layout.fragment_pokemon) {
private var _binding : FragmentPokemonBinding? = null
private val binding get() = _binding!!
private lateinit var dataPagingAdapter: PokemonPagingAdapter
private val viewModel: PokemonViewModel by viewModels {
ViewModelFactory()
}
private lateinit var comm: Communicator
override fun onStart() {
super.onStart()
getData()
}
override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
super.onViewCreated(view, savedInstanceState)
_binding = FragmentPokemonBinding.bind(view)
val toolBar = requireActivity().findViewById<View>(R.id.tool_bar)
toolBar.visibility = View.VISIBLE
val navBar = requireActivity().findViewById<BottomNavigationView>(R.id.bottom_navigation)
navBar.visibility = View.VISIBLE
comm = requireActivity() as Communicator
setupListPokemon()
}
private fun setupListPokemon(){
dataPagingAdapter = PokemonPagingAdapter(requireContext())
dataPagingAdapter.setOnItemClick(object: PokemonPagingAdapter.OnAdapterListener{
override fun onClick(data: Result, name: String, url: String) {
comm.passDataCom(name, url)
}
})
binding.apply {
rvPokemon.layoutManager = LinearLayoutManager(context)
rvPokemon.setHasFixedSize(true)
rvPokemon.adapter = dataPagingAdapter
}
}
private fun getData(){
viewModel.allPokemonList.observe(viewLifecycleOwner){
dataPagingAdapter.submitData(lifecycle, it)
binding.btnCoba.setOnClickListener { btn ->
if (it == null){
Log.e("ResponseFailed", it.toString())
} else Log.e("ResponseSucceed", it.toString())
}
}
}
}
What's the reason? I have followed the step by step implementation of paging 3 but the data still doesn't appear either.
I don't know the API you are using, but it seems that you are using it incorrectly. The getAllPokemon method has limit and offset parameters and you are calling it like apiService.getAllPokemon(position, params.loadSize), so you are using position as a limit and params.loadSize as an offset.
You should pass params.loadSize as a limit, rename INITIAL_PAGE_INDEX to INITIAL_OFFSET and set it to 0, since your API uses offsets instead of pages (at least it seems so from what you provided). The load function should then look something like this:
// get current offset
val offset = params.key ?: INITIAL_OFFSET
val responseData = apiService.getAllPokemon(limit = params.loadSize, offset = offset)
val prevKey = offset - params.loadSize
val nextKey = offset + params.loadSize
I am using flow to get data after any changes in my room database ,my app is note and it use SELECT by searching and filter by priority [High,Normal,Low]. and it has delete and update and insert too. I get flows from model and in viewModel by search and filter I Collect my data from flows and post it to my single liveData and in the last I get them in my Observer in the view
my problem is after in SELECT when I use UPDATE or INSERTT or DELETE , all of my old SELECT(search and filter) repeat in the moment. it means if I search 1000 once, and use filter to my notes 99 once; I will collect 1099 flows in the moment again and my observer in the my view will be bombing!!!
My Dao:
#Dao
interface NoteDao {
#Insert(onConflict = OnConflictStrategy.REPLACE)
suspend fun saveNote(entity : NoteEntity)
#Delete
suspend fun deleteNote(note : NoteEntity)
#Update
suspend fun updateNote(note : NoteEntity)
#Query("SELECT * FROM $NOTE_TABLE")
fun getAllNotes() : Flow<MutableList<NoteEntity>>
#Query("SELECT * FROM $NOTE_TABLE WHERE id == :id")
fun getNote(id : Int) : Flow<NoteEntity>
#Query("SELECT * FROM $NOTE_TABLE WHERE priority == :priority")
fun fileNote(priority : String) : Flow<MutableList<NoteEntity>>
#Query("SELECT * FROM $NOTE_TABLE WHERE title LIKE '%' || :title || '%'")
fun searchNote(title : String) : Flow<MutableList<NoteEntity>>
}
My Repository:
class MainRepository #Inject constructor(private val dao : NoteDao) {
fun getAllNotes() = dao.getAllNotes()
fun getNotesByPriority(priority : String) = dao.fileNote(priority)
fun getNotesBySearch(title : String) = dao.searchNote(title)
suspend fun deleteNote(note: NoteEntity) = dao.deleteNote(note)
}
My ViewModel:
#HiltViewModel
class MainViewModel #Inject constructor(private val repository: MainRepository) : ViewModel() {
val notesData = object : MutableLiveData<DataStatus<MutableList<NoteEntity>>>(){
override fun postValue(value: DataStatus<MutableList<NoteEntity>>?) {
super.postValue(value)
Log.e("TAGJH", "postValue: ${value?.data?.size}")
}
}
fun getAllNotes() = viewModelScope.launch {
repository.getAllNotes().collect {
Log.e("TAGJH", "getAll: ${it.size}")
notesData.postValue(DataStatus.success(it, it.isEmpty()))
}
}
fun getNoteByPriority(priority: String) = viewModelScope.launch {
repository.getNotesByPriority(priority).collect {
Log.e("TAGJH", "priority ${it.size }->$priority")
notesData.postValue(DataStatus.success(it, it.isEmpty()))
}
}
fun getNoteBySearch(characters: String) = viewModelScope.launch {
repository.getNotesBySearch(characters).collect {
Log.e("TAGJH", "collect: ${it.size}")
notesData.postValue(DataStatus.success(it, it.isEmpty()))
}
}
fun deleteNote(note: NoteEntity) = viewModelScope.launch {
repository.deleteNote(note)
}
}
My View:
#AndroidEntryPoint
class MainActivity : AppCompatActivity() {
private var selectedItem: Int = 0
private var _binding: ActivityMainBinding? = null
private val binding get() = _binding
#Inject
lateinit var noteAdapter: NoteAdapter
#Inject
lateinit var noteEntity: NoteEntity
private val viewModel: MainViewModel by viewModels()
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
_binding = ActivityMainBinding.inflate(layoutInflater)
setContentView(binding?.root)
binding?.apply {
setSupportActionBar(notesToolbar)
addNoteBtn.setOnClickListener {
NoteFragment().show(supportFragmentManager, NoteFragment().tag)
}
viewModel.notesData.observe(this#MainActivity) {
showEmpty(it.isEmpty)
noteAdapter.setData(it.data!!)
noteList.apply {
layoutManager =
StaggeredGridLayoutManager(2, StaggeredGridLayoutManager.VERTICAL)
adapter = noteAdapter
}
}
viewModel.getAllNotes()
notesToolbar.setOnMenuItemClickListener {
when (it.itemId) {
R.id.actionFilter -> {
filterByProperty()
return#setOnMenuItemClickListener true
}
else -> return#setOnMenuItemClickListener false
}
}
deleteAndUpdateListener()
}
}
private fun deleteAndUpdateListener() =
noteAdapter.onItemClickListener { note, title ->
when (title) {
DELETE -> {
noteEntity.id = note.id
noteEntity.title = note.title
noteEntity.des = note.des
noteEntity.priority = note.priority
noteEntity.category = note.category
viewModel.deleteNote(noteEntity)
}
EDIT -> {
val noteFragment = NoteFragment()
val bundle = Bundle()
bundle.putInt(BUNDLE_ID, note.id)
noteFragment.arguments = bundle
noteFragment.show(supportFragmentManager, NoteFragment().tag)
}
}
}
private fun showEmpty(isShown: Boolean) {
binding?.apply {
if (isShown) {
emptyShowing.visibility = View.VISIBLE
noteList.visibility = View.GONE
} else {
emptyShowing.visibility = View.GONE
noteList.visibility = View.VISIBLE
}
}
}
override fun onDestroy() {
super.onDestroy()
_binding = null
}
override fun onCreateOptionsMenu(menu: Menu): Boolean {
menuInflater.inflate(R.menu.menu_toolbar, menu)
val search = menu.findItem(R.id.actionSearch)
val searchView = search.actionView as SearchView
searchView.queryHint = getString(R.string.search)
searchView.setOnQueryTextListener(object : SearchView.OnQueryTextListener {
override fun onQueryTextSubmit(query: String?): Boolean {
return false
}
override fun onQueryTextChange(newText: String): Boolean {
viewModel.getNoteBySearch(newText)
Log.e("TAGJH", "searching")
return true
}
})
return super.onCreateOptionsMenu(menu)
}
private fun filterByProperty() {
val builder = AlertDialog.Builder(this)
val priories = arrayOf(ALL, HIGH, NORMAL, LOW)
builder.setSingleChoiceItems(priories, selectedItem) { dialog, item ->
when (item) {
0 -> {
viewModel.getAllNotes()
}
in 1..3 -> {
viewModel.getNoteByPriority(priories[item])
}
}
selectedItem = item
dialog.dismiss()
}
val dialog: AlertDialog = builder.create()
dialog.show()
}
}
I want to see my note after any update or delete or insert is updating in my last SELECT from room database
I have an application using databinding, livedata, room, kotlin koroutines, viewmodel, retrofit and koin. I have one activity, and two fragments.
UserListFragment: Show in a recyclerview a list of user items.
UserFullProfileFragment: Show the user item detail.
When the application is running, an external API is called to retrieve a list of users and display it in a recyclerview. Then, if I click on one item, an external API is called to get the detail of the current user whith its ID.
The problem is when I click on one item at the first, everything is going well but for following items, this is the detail of previous item which is displayed and so on and so forth.
Any ideas ?
UserRepository:
class UserRepositoryImpl (private val userApi: UserApi, private val userDao: UserDao, private val networkStateManager: NetworkStateManager) : UserRepository {
override suspend fun getUserList(): Result<List<UserListItem>> {
if (networkStateManager.hasNetWorkConnection()) {
return try {
// get user list from user API
val response = userApi.getUserList()
if (response.isSuccessful) {
Log.d("REPO", "get users from api")
response.body()?.let { userResponse ->
Log.d("REPO", "response:$response")
val userList = userResponse.data
// convert user API object to user entity
val entities = userList.map { it.toUserEntity() }
// save user list in database
withContext(Dispatchers.IO) { userDao.addUsers(entities) }
// convert user entity to user model
val userItemList = entities.map { it.toUserListItem() }
return Result.Success(userItemList)
} ?: handleFailure(response)
} else {
handleFailure(response)
}
} catch (e: Exception) {
return Result.Failure(e, e.localizedMessage)
}
} else {
// get user list from database if no network
val data = withContext(Dispatchers.IO) { userDao.findAllUsers() }
return if (data.isNotEmpty()) {
Log.d("REPO", "get users from db")
val userItemList = data.map { it.toUserListItem() }
Result.Success(userItemList)
} else {
Result.Failure(Exception("error"), "no network connection")
}
}
}
override suspend fun getUserFullProfile(userId: String): Result<UserFullProfile> {
if (networkStateManager.hasNetWorkConnection()) {
return try {
// get user from user API
val response = userApi.getUserFullProfile(userId)
if (response.isSuccessful) {
Log.d("REPO", "get users from api")
response.body()?.let { userResponse ->
Log.d("REPO", "response:$userResponse")
// convert user API object to user entity
val userEntity = userResponse.toUserEntity()
// save user data in database
withContext(Dispatchers.IO) { userDao.addUserFullProfile(userEntity) }
// convert user entity to user model
val user = userEntity.toUserFullProfile()
return Result.Success(user)
} ?: handleFailure(response)
} else {
handleFailure(response)
}
} catch (e: Exception) {
return Result.Failure(e, e.localizedMessage)
}
} else {
// get user from database if no network
val data = withContext(Dispatchers.IO) { userDao.getUserById(userId) }
return if (data != null) {
Log.d("REPO", "get users from db")
val user = data.toUserFullProfile()
Result.Success(user)
} else {
Result.Failure(Exception("error"), "no network connection")
}
}
}
UserViewModel:
getUserList and getUserFullProfile are use cases which call the repository
class UserViewModel (private val getUserList: GetUserList, private val getUserFullProfile: GetUserFullProfile) : ViewModel() {
val userList = MutableLiveData<List<UserListItem>>()
val userFullProfile = MutableLiveData<UserFullProfile>()
fun getUserList() {
viewModelScope.launch {
when (val result = getUserList.getUserList()) {
is Result.Success -> userList.value = result.successData
is Result.Failure -> result.exception.localizedMessage
}
}
}
fun getUserFullProfile(userId: String) {
viewModelScope.launch {
when (val result = getUserFullProfile.getUserFullProfile(userId)) {
is Result.Success -> userFullProfile.value = result.successData
is Result.Failure -> result.exception.localizedMessage
}
}
}
UserRecyclerAdaper:
class UserRecyclerAdapter(private val context: Context?, val clickListener: UserClickListener) : RecyclerView.Adapter<UserRecyclerAdapter.UserViewHolder>() {
var userList : List<UserListItem> = ArrayList()
override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): UserViewHolder {
val inflatedView: UserItemBinding = DataBindingUtil.inflate(LayoutInflater.from(parent.context), R.layout.user_item, parent, false)
return UserViewHolder(inflatedView)
}
override fun onBindViewHolder(holder: UserViewHolder, position: Int) {
holder.bindUser(position)
}
override fun getItemCount() = userList.size
fun setUsers(users: List<UserListItem>) {
this.userList = users
notifyDataSetChanged()
}
inner class UserViewHolder(private val v: UserItemBinding) : RecyclerView.ViewHolder(v.root) {
fun bindUser(position: Int) {
val item = userList[position]
Log.d("ADAPTER", item.toString())
v.user = item
Picasso.get()
.load(item.picture)
.placeholder(R.drawable.ic_launcher_foreground)
.error(R.drawable.ic_launcher_background)
.into(v.picture)
v.userClickInterface = clickListener
v.root.setOnClickListener {
clickListener.onItemClick(item)
}
}
}
UserListFragment:
class UserListFragment : Fragment(), UserClickListener {
private val userViewModel by viewModel<UserViewModel>()
private lateinit var userAdapter: UserRecyclerAdapter
private lateinit var viewDataBinding: FragmentUserListBinding
override fun onCreateView(
inflater: LayoutInflater,
container: ViewGroup?,
savedInstanceState: Bundle?
): View {
viewDataBinding = DataBindingUtil.inflate(inflater, R.layout.fragment_user_list, container, false)
viewDataBinding.lifecycleOwner = this
return viewDataBinding.root
}
override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
super.onViewCreated(view, savedInstanceState)
recyclerView.layoutManager = LinearLayoutManager(activity, LinearLayoutManager.VERTICAL, false)
userAdapter = UserRecyclerAdapter(context, this)
recyclerView.adapter = userAdapter
recyclerView.isNestedScrollingEnabled = false
viewDataBinding.viewModel = userViewModel
userViewModel.getUserList()
userViewModel.userList.observe(viewLifecycleOwner, { userList ->
if (userList.isNotEmpty() && userList != null) {
userAdapter.setUsers(userList)
}
})
}
override fun onItemClick(user: UserListItem) {
Log.d("FRAGMENT", user.toString())
userViewModel.getUserFullProfile(user.id)
userViewModel.userFullProfile.observe(viewLifecycleOwner, { userFullProfile ->
Log.d("UFP", userFullProfile.toString())
if (userFullProfile != null) {
(activity as MainActivity).replaceFragment(UserFullProfileFragment.newInstance(userFullProfile),
R.id.fragment_layout, "userFullProfile")
}
})
}
UserFullProfileFragment:
class UserFullProfileFragment : Fragment() {
companion object {
#JvmStatic
fun newInstance(user: UserFullProfile) = UserFullProfileFragment().apply {
arguments = Bundle().apply {
putParcelable("user", user)
}
}
}
private var user: UserFullProfile? = null
private lateinit var mViewDataBinding: FragmentUserFullProfileBinding
override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
super.onViewCreated(view, savedInstanceState)
mViewDataBinding.user = user
notify()
Picasso.get()
.load(mViewDataBinding.user?.picture)
.placeholder(R.drawable.ic_launcher_foreground)
.error(R.drawable.ic_launcher_background)
.into(mViewDataBinding.picture)
val dateOfBirth = parseDate(mViewDataBinding.user?.dateOfBirth)
mViewDataBinding.dateOfBirth.text = dateOfBirth
val registerDate = parseDate(mViewDataBinding.user?.registerDate)
mViewDataBinding.registerDate.text = registerDate
}
override fun onAttach(context: Context) {
super.onAttach(context)
user = arguments?.getParcelable("user")
Log.d("APP", user.toString())
}
override fun onCreateView(
inflater: LayoutInflater,
container: ViewGroup?,
savedInstanceState: Bundle?
): View {
mViewDataBinding = DataBindingUtil.inflate(inflater,
R.layout.fragment_user_full_profile, container, false)
mViewDataBinding.lifecycleOwner = this
return mViewDataBinding.root
}
Thank you :)
Finally, I found a solution :
I pass the user id argment from UserListFragment to UserFullProfileFragment instead of the current user object and I call the external API to get the current user in the UserFullProfileFragment.
This is the final code:
UserListFragment:
override fun onItemClick(user: UserListItem) {
val action = UserListFragmentDirections.actionUserListFragmentToUserFullProfileFragment(user.id)
findNavController().navigate(action)
}
UserFullProfileFragment:
class UserFullProfileFragment : Fragment() {
private lateinit var userID: String
private var mViewDataBinding: FragmentUserFullProfileBinding? = null
private val binding get() = mViewDataBinding!!
private val userViewModel by viewModel<UserViewModel>()
override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
super.onViewCreated(view, savedInstanceState)
binding.viewModel = userViewModel
userID = UserFullProfileFragmentArgs.fromBundle(requireArguments()).userArgs
userViewModel.getUserFullProfile(userID)
userViewModel.userFullProfile.observe(viewLifecycleOwner, { userFullProfile ->
if (userFullProfile != null) {
binding.user = userFullProfile
Picasso.get()
.load(binding.user?.picture)
.placeholder(R.drawable.ic_launcher_foreground)
.error(R.drawable.ic_launcher_background)
.into(binding.picture)
val dateOfBirth = parseDate(binding.user?.dateOfBirth)
binding.dateOfBirth.text = dateOfBirth
val registerDate = parseDate(binding.user?.registerDate)
binding.registerDate.text = registerDate
}
})
}
override fun onCreateView(
inflater: LayoutInflater,
container: ViewGroup?,
savedInstanceState: Bundle?
): View {
mViewDataBinding = DataBindingUtil.inflate(inflater,
R.layout.fragment_user_full_profile, container, false)
binding.lifecycleOwner = this
return binding.root
}
override fun onDestroyView() {
super.onDestroyView()
mViewDataBinding = null
}
}
I am trying to display RESTful Api in recycler view in fragment. When app runs it shows no error but loads nothing in recycler view. I logged response in PagingSource file and it shows correct data but still nothing is displayed in recycler view.
This is my Api interface:
interface Api {
companion object {
const val BASE_URL = "http://be7c232bf30e.ngrok.io"
}
#GET("/posts")
suspend fun searchPosts(
#Query("_page") page: Int,
#Query("_limit") perPage: Int
): List<SocialNetworkPost>
}
This is my PagingSource file:
private const val STARTING_PAGE_INDEX = 1
class PagingSource(private val api: Api) : PagingSource<Int, SocialNetworkPost>() {
override suspend fun load(params: LoadParams<Int>): LoadResult<Int, SocialNetworkPost> {
val position = params.key ?: STARTING_PAGE_INDEX
return try {
val response = api.searchPosts(position, params.loadSize)
LoadResult.Page(
data = response,
prevKey = if (position == STARTING_PAGE_INDEX) null else position - 1,
nextKey = if (response.isEmpty()) null else position + 1
)
} catch (exception: IOException) {
LoadResult.Error(exception)
} catch (exception: HttpException) {
LoadResult.Error(exception)
}
}
}
This is my repository:
#Singleton
class Repository #Inject constructor(private val api: Api) {
fun getPostsResults() = Pager(
config = PagingConfig(
pageSize = 20,
maxSize = 100,
enablePlaceholders = false
),
pagingSourceFactory = { PagingSource(api) }
).liveData
}
This is Fragment in which recyclerView is:
override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
super.onViewCreated(view, savedInstanceState)
val postAdapter = PostsAdapter(this)
binding.apply {
recyclerView.apply {
setHasFixedSize(true)
itemAnimator = null
adapter = postAdapter.withLoadStateHeaderAndFooter(
header = PostsLoadStateAdapter { postAdapter.retry() },
footer = PostsLoadStateAdapter { postAdapter.retry() }
)
buttonRetry.setOnClickListener {
postAdapter.retry()
}
}
}
viewModel.posts.observe(viewLifecycleOwner) {
postAdapter.submitData(viewLifecycleOwner.lifecycle, it)
}
postAdapter.addLoadStateListener { loadState ->
binding.apply {
progressBar.isVisible = loadState.source.refresh is LoadState.Loading
recyclerView.isVisible = loadState.source.refresh is LoadState.NotLoading
buttonRetry.isVisible = loadState.source.refresh is LoadState.Error
textViewError.isVisible = loadState.source.refresh is LoadState.Error
// empty view
if (loadState.source.refresh is LoadState.NotLoading && loadState.append.endOfPaginationReached && postAdapter.itemCount < 1) {
recyclerView.isVisible = false
textViewEmpty.isVisible = true
} else {
textViewEmpty.isVisible = false
}
}
}
}
override fun onDestroyView() {
super.onDestroyView()
_binding = null
}
override fun onItemClick(post: SocialNetworkPost) {
val action = HomeFragmentDirections.actionHomeFragmentToDetailsFragment(post)
findNavController().navigate(action)
}
}
This is my repository:
class HomeViewModel #ViewModelInject constructor(private val repository: Repository) : ViewModel() {
val posts = repository.getPostsResults().cachedIn(viewModelScope)
}
This is my adapter:
class PostsAdapter(private val listener: OnItemClickListener) : PagingDataAdapter<SocialNetworkPost, PostsAdapter.PostViewHolder>(POSTS_COMPARATOR) {
override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): PostViewHolder {
val binding = ItemPostBinding.inflate(LayoutInflater.from(parent.context), parent, false)
return PostViewHolder(binding)
}
override fun onBindViewHolder(holder: PostViewHolder, position: Int) {
val currentItem = getItem(position)
if (currentItem != null) {
Log.d("PostAdapter", "onBindViewHolder: if")
holder.bind(currentItem)
} else {
Log.d("PostAdapter", "onBindViewHolder: else")
}
}
inner class PostViewHolder(private val binding: ItemPostBinding) : RecyclerView.ViewHolder(binding.root) {
init {
binding.root.setOnClickListener {
val position = bindingAdapterPosition
if (position != RecyclerView.NO_POSITION) {
val item = getItem(position)
if (item != null) listener.onItemClick(item)
}
}
}
fun bind(post: SocialNetworkPost) {
Log.d("PostAdapter", "bind: $post")
binding.apply {
Glide.with(itemView)
.load(post.accountIcon)
.centerCrop()
.transition(DrawableTransitionOptions.withCrossFade())
.error(R.drawable.ic_account)
.into(imageViewProfilePicture)
textViewName.text = post.accountName
textViewDescription.text = post.description
Glide.with(itemView)
.load(post.descriptionImage)
.centerCrop()
.transition(DrawableTransitionOptions.withCrossFade())
.error(R.drawable.empty)
.into(imageViewDescription)
textViewLikesAmount.text = "Likes: ${post.likesAmount}"
textViewCommentsAmount.text = "Comments: ${post.commentsAmount}"
}
}
}
interface OnItemClickListener {
fun onItemClick(post: SocialNetworkPost)
}
companion object {
private val POSTS_COMPARATOR = object : DiffUtil.ItemCallback<SocialNetworkPost>() {
override fun areItemsTheSame(oldItem: SocialNetworkPost, newItem: SocialNetworkPost) = oldItem.id == newItem.id
override fun areContentsTheSame(oldItem: SocialNetworkPost, newItem: SocialNetworkPost) = oldItem == newItem
}
}
}
RecyclerView needs a layoutManager, you can set it in the xml:
app:layoutManager="androidx.recyclerview.widget.LinearLayoutManager"
or programatically:
recyclerView.layoutManager = LinearLayoutManager(requireContext())
I am using the following DAO
#Dao
interface GroceryListDao {
#Insert
fun insert(list: GroceryList)
#Update
fun update(list: GroceryList)
#Query("Delete from grocery_list_table")
fun clear()
#Query ("Select * from grocery_list_table")
fun getAllItems(): LiveData<List<GroceryList>>
#Query ("Select * from grocery_list_table where itemId = :item")
fun getItem(item: Long): GroceryList?
#Query ("Select * from grocery_list_table where item_status = :status")
fun getItemsBasedOnStatus(status: Int): List<GroceryList>
}
And my database has 3 columns groceryId(Long - autogenerated), groceryName(String) and groceryStatus(Int - 1/0).
When I am using getItemsBasedOnStatus(status: Int) without using LiveData I am able to retrieve the data. But when it is wrapped with LiveData I am getting null.
The other issue is when I get a list of items from a database without wrapping with LiveData and assigning to MutableLiveData in ViewModel, then the assigned MutableLiveData is displaying null values. I see lot of questions on this but no answer.
Adding code for my viewModel and Fragment
ViewModel
class GroceryListViewModel(
val database: GroceryListDao,
application: Application
) : AndroidViewModel(application) {
private var viewModelJob = Job()
private val uiScope = CoroutineScope(Dispatchers.Main + viewModelJob)
var grocerylistItems = database.getAllItems()
var groceryItem = MutableLiveData<GroceryList>()
var groceryitems = MutableLiveData<List<GroceryList>>()
init {
getAllItemsFromDatabase()
}
fun insertIntoDatabase(item: GroceryList) {
uiScope.launch {
insert(item)
}
}
private suspend fun insert(item: GroceryList) {
withContext(Dispatchers.IO) {
database.insert(item)
}
}
fun updateGrocerylist(itemId: Long, status: Int) {
uiScope.launch {
groceryItem.value = getItem(itemId)
groceryItem.value?.itemStatus = status
groceryItem.value?.let { update(it) }
}
}
private suspend fun update(item: GroceryList) {
withContext(Dispatchers.IO) {
database.update(item)
}
}
private suspend fun getItem(itemId: Long): GroceryList? {
return withContext(Dispatchers.IO) {
var item = database.getItem(itemId)
item
}
}
fun getAllItemsFromDatabase() {
uiScope.launch {
getAllItems()
}
}
private suspend fun getAllItems() {
withContext(Dispatchers.IO) {
grocerylistItems = database.getAllItems()
}
}
fun getPendingItemsFromDatabase(status: Int) {
uiScope.launch {
getPendingItems(status)
}
}
private suspend fun getPendingItems(status: Int) {
withContext(Dispatchers.IO) {
val items = database.getItemsBasedOnStatus(status)
groceryitems.postValue(items)
Log.i("Grocery List", "Pending Items:" + items.size)
}
}
fun getDoneItemsFromDatabase(status: Int) {
uiScope.launch {
getDoneItems(status)
}
}
private suspend fun getDoneItems(status: Int) {
withContext(Dispatchers.IO) {
val items = database.getItemsBasedOnStatus(status)
groceryitems.postValue(items)
Log.i("Grocery List", "Done Items:" + items.size)
}
}
fun clearAllItemsFromDatabase() {
uiScope.launch {
clearItems()
}
}
private suspend fun clearItems() {
withContext(Dispatchers.IO) {
database.clear()
getAllItemsFromDatabase()
}
}
override fun onCleared() {
super.onCleared()
viewModelJob.cancel()
}
}
Fragment
class GroceryLIstFragment : Fragment() {
override fun onCreateView(
inflater: LayoutInflater, container: ViewGroup?,
savedInstanceState: Bundle?
): View? {
// Inflate the layout for this fragment
val binding = FragmentGroceryLIstBinding.inflate(inflater,container,false)
val application = requireNotNull(this.activity).application
val dataSource = GroceryDatabase.getInstance(application)?.groceryListDatabaseDao
val viewModelFactory = dataSource?.let { GroceryListViewModelFactory(it, application) }
val viewModel = viewModelFactory?.let {
ViewModelProvider(
this,
it
).get(GroceryListViewModel::class.java)
}
viewModel?.grocerylistItems?.observe(this , Observer {
binding.grocerylistView.removeAllViews() // is it correct ?
for (item in it){
Log.i("Grocery List","Grocery Id=" + item.itemId+" ,Grocery Name=" + item.itemName +", Grocery status="+item.itemStatus)
addItemToScrollbar(item, binding, viewModel)
}
})
binding.addGrocery.setOnClickListener {
val imm = context?.getSystemService(Context.INPUT_METHOD_SERVICE) as InputMethodManager
imm.hideSoftInputFromWindow(view?.windowToken, 0)
val item = binding.groceryitemField.text.toString()
if (!item.isNullOrBlank()) {
val newItem = GroceryList(itemName = item)
viewModel?.insertIntoDatabase(newItem)
if (viewModel != null) {
addItemToScrollbar(newItem, binding,viewModel)
}
binding.groceryitemField.text.clear()
}
}
binding.doneCheckbox.setOnClickListener {
if (binding.doneCheckbox.isChecked)
viewModel?.getDoneItemsFromDatabase(1)
else
viewModel?.getAllItemsFromDatabase()
}
binding.pendingCheckbox.setOnClickListener {
if (binding.pendingCheckbox.isChecked) {
viewModel?.getPendingItemsFromDatabase(0)
}
else
viewModel?.getAllItemsFromDatabase()
}
binding.clearGrocery.setOnClickListener {
viewModel?.clearAllItemsFromDatabase()
binding.grocerylistView.removeAllViews()
}
return binding.root
}
private fun addItemToScrollbar(
item: GroceryList,
binding: FragmentGroceryLIstBinding,
viewModel: GroceryListViewModel
) {
val itemBox = AppCompatCheckBox(context)
itemBox.text = item.itemName
itemBox.isChecked = item.itemStatus == 1
binding.grocerylistView.addView(itemBox)
itemBox.setOnClickListener {
val itemstatus: Int = if (itemBox.isChecked)
1
else {
0
}
viewModel?.updateGrocerylist(item.itemId,itemstatus)
}
}
}
Any help would be appreciated.
This most likely the same issue as here (read the linked answer). Due to way asynchronous way LiveData is working, it will return null when you call it. LiveData is meant to be used in conjunction with Observers, that will be triggered once changes to observed subject occur.
An Observer can look like this
database.getItemsBasedOnStatus(status).observe(viewLifecycleOwner, Observer { groceryList->
// Do cool grocery stuff here
})
If you want to retrieve your data inside your ViewModel you do not have a viewLifecycleOwner, you can then use "observeForever()", but then you have to remove the Observer explicitly, see this answer.
Same issue and answer also in this post