I am implementing a RecyclerView in a fragment. The XML should be correct since I tried it with my hard-coded data, and the API call does return the correct json data from the server according to the Log in the console. The problem is that the RecyclerView adapter does not get any data from my Observable. Here is my implementation
In PostDataService interface I used Retrofit to get an Observable>
interface PostDataService {
#GET(".")
fun getPosts(
#Query(value = "offset") offset: Long = 0,
#Query(value = "limit") limit: Long = 10,
#Query(value = "subscribedOnly") subscribedOnly: Boolean = false
): Observable<List<Post>>
companion object {
val retrofit: PostDataService = Retrofit.Builder()
.baseUrl("http:aws/api/post/")
.addCallAdapterFactory(RxJava2CallAdapterFactory.create())
.addConverterFactory(MoshiConverterFactory.create())
.client(client)
.build()
.create(PostDataService::class.java)
}
}
In PostListRepository, I used RxJava operators to get the LiveData
class PostListRepository {
private val postListLiveData: MutableLiveData<List<Post>> = MutableLiveData()
private val compositeDisposable: CompositeDisposable = CompositeDisposable()
fun getPostListLiveData(): MutableLiveData<List<Post>> {
val postList: MutableList<Post> = ArrayList()
val retrofitInstance = PostDataService.retrofit
val postListObservable = retrofitInstance.getPosts()
compositeDisposable.add(
postListObservable
.subscribeOn(Schedulers.io())
.observeOn(AndroidSchedulers.mainThread())
.flatMapIterable { it }
.subscribeWith(object : DisposableObserver<Post>() {
override fun onError(e: Throwable) {
// if some error happens in our data layer our app will not crash, we will
// get error here
}
override fun onNext(post: Post) {
postList.add(post)
}
override fun onComplete() {
postListLiveData.postValue(postList)
}
})
)
return postListLiveData
}
fun clear() {
compositeDisposable.clear()
}
}
In PostListViewModel, I passed the LiveData from the repository into this ViewModel.
class PostListViewModel : ViewModel() {
private var postListRepository: PostListRepository = PostListRepository()
fun getPostList(): MutableLiveData<List<Post>> {
return postListRepository.getPostListLiveData()
}
fun clear() {
postListRepository.clear()
}
}
Here is the Fragment that contains the RecyclerView. I think the .oberserve function in getPostList() is not called since I tried Log it but got nothing.
class PostListFragment : Fragment() {
private lateinit var recyclerView: RecyclerView
private lateinit var swipeLayout: SwipeRefreshLayout
private lateinit var postListViewModel: PostListViewModel
private val postListAdapter = PostRecyclerViewAdapter()
override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?): View? {
val rootView = inflater.inflate(R.layout.view_post_list, container, false)
recyclerView = rootView.findViewById(R.id.postRecyclerView)
recyclerView.apply {
setHasFixedSize(true)
addItemDecoration(VerticalSpaceItemDecoration(36))
layoutManager = LinearLayoutManager(context)
adapter = postListAdapter
}
postListViewModel = ViewModelProviders.of(this).get(PostListViewModel::class.java)
getPostList()
swipeLayout = rootView.findViewById(R.id.swipeLayout)
swipeLayout.setColorSchemeResources(R.color.colorPrimary)
swipeLayout.setOnRefreshListener {
getPostList()
swipeLayout.isRefreshing = false
}
return rootView
}
override fun onDestroy() {
super.onDestroy()
postListViewModel.clear() // to avoid memory leak
}
private fun getPostList() {
postListViewModel.getPostList().observe(this, Observer<List<Post>> { resource ->
postListAdapter.setPostList(resource)
postListAdapter.notifyDataSetChanged()
})
}
}
Here is the adapter for the RecyclerView:
class PostRecyclerViewAdapter : RecyclerView.Adapter<PostViewHolder>() {
private var postList: List<Post> = ArrayList()
override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): PostViewHolder {
// create a new view
val postView = PostView(parent.context)
// set the view's size, margins, paddings and layout parameters
return PostViewHolder.from(postView)
}
override fun getItemCount(): Int = postList.size
override fun onBindViewHolder(holder: PostViewHolder, position: Int) {
val curPost = postList[position]
holder.postView.apply {
setPostOwnerDisplayName(curPost.content.userDisplayedName)
setPostOwnerRole(curPost.content.role)
setPostOwnerAvatar(R.mipmap.ic_launcher_round)
setPostText(curPost.content.text)
setPostImage(curPost.content.smallMediaPaths[0])
setLikeState(curPost.liked)
setBookmarkState(curPost.bookmarked)
}
}
fun setPostList(postList: List<Post>) {
this.postList = postList
}
}
As I mentioned above, I think the .oberserve function in getPostList() in PostListFragment is not called since I tried Log it but got nothing, so there is no data passed into the RecyclerView. Can anyone help me find the reason why it's not being called, or why it's not getting the data from the ViewModel?
I wouldn't think of this is related to your issue, but your code has potential problems.
To move observe part to onActivityCreated would be better to ensure view is created.
when your fragment view is re-created, a new Observer will be added, while previous one still alive, because your Observer is anonymous. So, you have to manage the observers to prevent it.
I just found out that I forgot to catch the exception in RxJava onNext() in case to get the moshi serialization error. After getting that, I got some moshi conversion errors.
Posted it in case anyone carelessly forgot to catch the moshi error.
Thanks!
Related
I've been trying to solve this problem for over 3 hours. Everything seems just fine on the Logcat and Debug mode. I'm fetching the List without any problem, Fragment is reading the MutableLiveData successfully. Only the notifyDataSetChanged() function is not working and also it doesn't give any error etc. If I send an ArrayList manually then it works but if it goes inside Retrofit and DisposableSingleObserver then even the manual list doesn't work.
I have tried every way that I could have found on the internet. I've looked for more than 20 different solution none of them have worked.
API - HoroscopeAPI.kt
interface HoroscopeAPI {
#GET("astraios/horoscopeList.json")
fun getHoroscope(): Single<List<Horoscope>>
}
Service - HoroscopeAPIService.kt
class HoroscopeAPIService {
private val BASE_URL = "https://wiuma.co"
private val api = Retrofit.Builder()
.baseUrl(BASE_URL)
.addConverterFactory(GsonConverterFactory.create())
.addCallAdapterFactory(RxJava2CallAdapterFactory.create())
.build()
.create(HoroscopeAPI::class.java)
fun getData(): Single<List<Horoscope>> {
return api.getHoroscope()
}
}
ViewModel - HoroscopeViewModel.kt
class HoroscopeViewModel : ViewModel() {
private val horoscopeApiService = HoroscopeAPIService()
private val disposable = CompositeDisposable()
val horoscopeList = MutableLiveData<List<Horoscope>>()
fun getDataFromAPI() {
loadingStatus.value = true
disposable.add(
horoscopeApiService.getData()
.subscribeOn(Schedulers.newThread())
.observeOn(AndroidSchedulers.mainThread())
.subscribeWith(object : DisposableSingleObserver<List<Horoscope>>() {
override fun onSuccess(t: List<Horoscope>) {
horoscopeList.value = t
}
override fun onError(e: Throwable) {
e.printStackTrace()
}
})
)
}
}
Fragment - Horoscope.kt
override fun onCreateView(
inflater: LayoutInflater,
container: ViewGroup?,
savedInstanceState: Bundle?
): View? {
horoscopeViewModel =
ViewModelProvider(this).get(HoroscopeViewModel::class.java)
val root = inflater.inflate(R.layout.fragment_horoscope, container, false)
horoscopeViewModel.getDataFromAPI()
horoscopeRecyclerView = root.findViewById(R.id.horoscopeRecyclerView)
horoscopeRecyclerView.layoutManager = LinearLayoutManager(context)
horoscopeRecyclerView.adapter = recyclerViewAdapter
observeData()
return root
}
fun observeData() {
horoscopeViewModel.horoscopeList.observe(viewLifecycleOwner, Observer { horoscope ->
horoscope?.let {
recyclerViewAdapter.updateList(horoscope)
}
})}
**Adapter - HoroscopeRecyclerAdapter.kt **
class HoroscopeRecyclerAdapter(val horoscopeList: ArrayList<Horoscope>) :
RecyclerView.Adapter<HoroscopeRecyclerAdapter.HoroscopeViewHolder>() {
class HoroscopeViewHolder(itemView: View) : RecyclerView.ViewHolder(itemView) {
}
override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): HoroscopeViewHolder {
val inflater = LayoutInflater.from(parent.context)
val view = inflater.inflate(R.layout.horoscope_recycler_row, parent, false)
return HoroscopeViewHolder(view)
}
#SuppressLint("SetTextI18n")
override fun onBindViewHolder(holder: HoroscopeViewHolder, position: Int) {
holder.itemView.horoscopeName.text = horoscopeList.get(position).nameHoroscope
holder.itemView.horoscopeDates.text =
horoscopeList.get(position).startDate + " " + horoscopeList.get(position).endDate
//TODO Gorsel baglantisi eklenecek.
holder.itemView.setOnClickListener {
val action =
HoroscopeFragmentDirections.actionNavigationHoroscopeToNavigationHoroscopeDetails(0)
Navigation.findNavController(it).navigate(action)
}
}
override fun getItemCount(): Int {
return horoscopeList.size
}
fun updateList(newHoroscopeList: List<Horoscope>) {
horoscopeList.clear()
horoscopeList.addAll(newHoroscopeList)
notifyDataSetChanged()
}}
I ran your project from Github. notifyDataSetChanged() seems to be working fine. The reason why the list items aren't showing up is that the visibility of the RecyclerView is set to GONE. It needs to be set back to VISIBLE when the results arrive:
fun observeData() {
horoscopeViewModel.horoscopeList.observe(viewLifecycleOwner, Observer { horoscope ->
horoscope?.let {
errorText.visibility = View.GONE
progressBar.visibility = View.GONE
horoscopeRecyclerView.visibility = View.VISIBLE
recyclerViewAdapter.updateList(it)
}
})
I'm learning Room with the sample project RoomWordsSample at https://github.com/googlecodelabs/android-room-with-a-view/tree/kotlin.
The following code are from the project.
In my mind, the LiveDate will update UI automatically when the data changed if it was observed.
But in the file WordListAdapter.kt, I find notifyDataSetChanged() is added to the function setWords(words: List<Word>)， it's seems that it must notify UI manually when data changed.
Why do it still need launch notifyDataSetChanged() when I have used LiveData ?
MainActivity.kt
class MainActivity : AppCompatActivity() {
private val newWordActivityRequestCode = 1
private lateinit var wordViewModel: WordViewModel
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
val recyclerView = findViewById<RecyclerView>(R.id.recyclerview)
val adapter = WordListAdapter(this)
recyclerView.adapter = adapter
recyclerView.layoutManager = LinearLayoutManager(this)
wordViewModel = ViewModelProvider(this).get(WordViewModel::class.java)
wordViewModel.allWords.observe(this, Observer { words ->
words?.let { adapter.setWords(it) }
})
}
}
WordViewModel.kt
class WordViewModel(application: Application) : AndroidViewModel(application) {
private val repository: WordRepository
val allWords: LiveData<List<Word>>
init {
val wordsDao = WordRoomDatabase.getDatabase(application, viewModelScope).wordDao()
repository = WordRepository(wordsDao)
allWords = repository.allWords
}
fun insert(word: Word) = viewModelScope.launch {
repository.insert(word)
}
}
WordListAdapter.kt
class WordListAdapter internal constructor(
context: Context
) : RecyclerView.Adapter<WordListAdapter.WordViewHolder>() {
private val inflater: LayoutInflater = LayoutInflater.from(context)
private var words = emptyList<Word>() // Cached copy of words
inner class WordViewHolder(itemView: View) : RecyclerView.ViewHolder(itemView) {
val wordItemView: TextView = itemView.findViewById(R.id.textView)
}
override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): WordViewHolder {
val itemView = inflater.inflate(R.layout.recyclerview_item, parent, false)
return WordViewHolder(itemView)
}
override fun onBindViewHolder(holder: WordViewHolder, position: Int) {
val current = words[position]
holder.wordItemView.text = current.word
}
internal fun setWords(words: List<Word>) {
this.words = words
notifyDataSetChanged()
}
override fun getItemCount() = words.size
}
Actually, livedata will give you updated data in your activity. But now, it is your activity's job to update the ui. So, whenever live data gives you updated data, you will have to tell the ui to update the data. Hence, notifyDataSetChanged().
notifyDataSetChanged has nothing to do with LiveData, it's part of RecyclerView api.
LiveData - is way of receiving data in lifecycle-aware way, RecyclerView simply displays views.
I'm working on a Grid RecyclerView for Scores App. Scores will be updated every 5 secs from API Call...
I'm using this library for my Recyclerview Adapter.
I'm using Observable Fields & List.
I need to update only the scores (textviews) but now the RecyclerView is getting updated every 5 secs.
Please Guide me in right direction. Thank you!
Full Code in Gist
class DashboardFragment : Fragment() {
private lateinit var dashboardViewModel: DashboardViewModel
private lateinit var binding: FragmentDashboardBinding
lateinit var retrofit: Retrofit
lateinit var apiService: APIService
lateinit var disposable: Disposable
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
dashboardViewModel = ViewModelProvider(this).get(DashboardViewModel::class.java)
fetchData()
}
override fun onCreateView(
inflater: LayoutInflater,
container: ViewGroup?,
savedInstanceState: Bundle?
): View? {
binding = DataBindingUtil
.inflate(inflater, R.layout.fragment_dashboard, container, false)
binding.viewModel = dashboardViewModel
return binding.root
}
fun fetchData() {
val interceptor = HttpLoggingInterceptor()
interceptor.setLevel(HttpLoggingInterceptor.Level.BODY)
val client = OkHttpClient.Builder()
.addInterceptor(interceptor)
.connectTimeout(30, TimeUnit.SECONDS)
.readTimeout(30, TimeUnit.SECONDS)
.writeTimeout(30, TimeUnit.SECONDS)
.build()
val gson = GsonBuilder()
.setLenient()
.create()
retrofit = Retrofit.Builder()
.baseUrl(APIService.BASE_URL)
.client(client)
.addCallAdapterFactory(RxJava2CallAdapterFactory.create())
.addConverterFactory(GsonConverterFactory.create(gson))
.build()
apiService = this.retrofit.create(APIService::class.java)
callIndicesEndpoint(null)
disposable = Observable.interval(1000, 2000, TimeUnit.MILLISECONDS)
.observeOn(AndroidSchedulers.mainThread())
.subscribe({ aLong: Long? -> this.refreshIndices(aLong)})
{ throwable: Throwable -> this.onError(throwable) }
}
#SuppressLint("CheckResult")
private fun callIndicesEndpoint(aLong: Long?) {
val observable =
apiService.indices
observable.subscribeOn(Schedulers.newThread()).observeOn(AndroidSchedulers.mainThread())
.map { result: ObservableArrayList<Indices> -> result }
.subscribe(
{ data: ObservableArrayList<Indices> ->
this.handleResults(data)
}
) { t: Throwable ->
this.handleError(t)
}
}
#SuppressLint("CheckResult")
private fun refreshIndices(aLong: Long?) {
val observable =
apiService.indices
observable.subscribeOn(Schedulers.newThread()).observeOn(AndroidSchedulers.mainThread())
.map { result: ObservableArrayList<Indices> -> result }
.subscribe({ data: ObservableArrayList<Indices> -> this.refreshResults(data)})
{ t: Throwable ->this.handleError(t)}
}
private fun handleResults(data: ObservableArrayList<Indices>) {
dashboardViewModel.populate(data)
}
private fun refreshResults(data: ObservableArrayList<Indices>) {
dashboardViewModel.refresh(data)
}
private fun onError(throwable: Throwable) {
Log.e(">>>", "ERROR")
}
private fun handleError(t: Throwable) {
Log.e("> >", t.localizedMessage + " - Err - " + t.cause)
//Add your error here.
}
override fun onPause() {
super.onPause()
disposable.dispose()
}
}
VIEWMODEL
class DashboardViewModel : ViewModel() {
val indices: ObservableList<Indices> = ObservableArrayList<Indices>()
fun populate(data: ArrayList<Indices>) {
indices.clear()
indices.addAll(data)
}
fun refresh(data: ArrayList<Indices>) {
// How to refresh only Items without recreating the List
}
val itemIds: ItemIds<Any> =
ItemIds { position, item -> position.toLong() }
val indicesItem: ItemBinding<Indices> =
ItemBinding.of<Indices>(BR.item, R.layout.item_futures)
}
You can use broadcast receiver functionality for update particular items from recyclerview .
I think what you need is to use DiffUtil, it'll be of great help as
DiffUtil figures out what has changed, RecyclerView can use that information to update only the items that were changed, added, removed, or moved, which is much more efficient than redoing the entire list.
Here is a course you can use to get a hand of it: https://codelabs.developers.google.com/codelabs/kotlin-android-training-diffutil-databinding/#3
When I had something like that I used the DiffUtil.
I had to update rates every X seconds and not change the whole list.
So the adapter should be something like this:
class RatesAdapter :
ListAdapter<Rate, RecyclerView.ViewHolder>(RateDiffCallback()) {
private val baseRateView = 0
private val rateView = 1
override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): RecyclerView.ViewHolder {
return if (viewType == rateView) {
RateHolder(
RateItemBinding.inflate(
LayoutInflater.from(parent.context), parent, false
)
)
} else {
BaseRateHolder(
BaseRateLayoutBinding.inflate(
LayoutInflater.from(parent.context), parent, false
)
)
}
}
override fun getItemViewType(position: Int): Int {
return if (position == 0) {
baseRateView
} else rateView
}
override fun onBindViewHolder(holder: RecyclerView.ViewHolder, position: Int) {
val rate = getItem(position)
if (holder.itemViewType == rateView) {
(holder as RateHolder).bind(rate)
holder.itemView.setOnClickListener {
swapper.itemSwap(rate)
}
} else {
(holder as BaseRateHolder).bind(rate)
}
}
class RateHolder(
private val binding: RateItemBinding
) : RecyclerView.ViewHolder(binding.root) {
fun bind(item: Rate) {
binding.apply {
rate = item
executePendingBindings()
}
}
}
class BaseRateHolder(
private val binding: BaseRateLayoutBinding
) : RecyclerView.ViewHolder(binding.root) {
fun bind(item: Rate) {
binding.apply {
rate = item
executePendingBindings()
}
}
val value = binding.value
}
}
private class RateDiffCallback : DiffUtil.ItemCallback<Rate>() {
override fun areItemsTheSame(oldItem: Rate, newItem: Rate): Boolean {
return oldItem.currencyCode == newItem.currencyCode
}
override fun areContentsTheSame(oldItem: Rate, newItem: Rate): Boolean {
return oldItem.rate == newItem.rate
}
}
Here I used binding in the adapter, and if you are not familiar with it, I will be more than happy to explain as well
In the Activity:
Before the onCreate:
private val ratesAdapter = RatesAdapter()
In the onCreate:
ratesList.adapter = ratesAdapter
Whenever you need to update the adapter including the first time you need to call it:
ratesAdapter.submitList(rates)
Rate is the model class that I am using
rates is the mutable list of < Rate >
ratesList is the recyclerview
try this : notifyItemChanged
with this:
listView.setItemAnimator(null);
I am trying to practice the android architecture components Paging
Local + Remote Datasource with Room, MVVM and LiveData
When i first time scroll the list(get remote data), it get into loop by onItemAtEndLoaded in PagedList.BoundaryCallback, but it scroll smooth when open the activity next time (get local data)
Here is my github link here!
Can anyone take a look and help me how to fix it, Thanks!
Activity
class PagingActivity : AppCompatActivity() {
lateinit var viewModel: PagingViewModel
lateinit var adapter: PagingAdapter
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_paging)
val factory = PagingViewModelFactory(PagingRepository(), application)
viewModel = ViewModelProviders.of(this,factory).get(PagingViewModel::class.java)
adapter = PagingAdapter()
recyclerView.adapter = adapter
viewModel.pagedListLiveData.observe(this, Observer {
adapter.submitList(it)
})
}
}
ViewModel
class PagingViewModel(repository: PagingRepository, application: Application) :
AndroidViewModel(application) {
val pagedListLiveData = repository.getDataItem(application)
}
Repository
class PagingRepository : PagingRepositoryCallback {
private lateinit var localDataSource: DataSource.Factory<Int, DataItem>
override fun getDataItem(application: Application): LiveData<PagedList<DataItem>> {
val pagedListLiveData: LiveData<PagedList<DataItem>> by lazy {
localDataSource = DataItemDbHelper(application).getRoomDataItemDao().getAllDataItem()
val config = PagedList.Config.Builder()
.setPageSize(25)
.setEnablePlaceholders(false)
.build()
LivePagedListBuilder(localDataSource, config)
.setBoundaryCallback(PagingBoundaryCallback(application))
.build()
}
return pagedListLiveData
}
}
interface PagingRepositoryCallback {
fun getDataItem(application: Application): LiveData<PagedList<DataItem>>
}
BoundaryCallback
class PagingBoundaryCallback(context: Context) :
PagedList.BoundaryCallback<DataItem>() {
private var page = 2
private val api = AllPlayerApi.api
private val dao = DataItemDbHelper(context).getRoomDataItemDao()
override fun onZeroItemsLoaded() {
super.onZeroItemsLoaded()
api.getAllPlayer().enqueue(createWebserviceCallback())
}
override fun onItemAtEndLoaded(itemAtEnd: DataItem) {
super.onItemAtEndLoaded(itemAtEnd)
api.getAllPlayer(page).clone().enqueue(createWebserviceCallback())
}
private fun createWebserviceCallback(): Callback<AllPlayerData> {
return object : Callback<AllPlayerData> {
override fun onFailure(call: Call<AllPlayerData>?, t: Throwable?) {
Log.d("Huang", " get player fail ")
}
override fun onResponse(call: Call<AllPlayerData>?, response: Response<AllPlayerData>) {
Log.d("Huang", " onResponse " + page)
response.body()!!.data!!.forEach {
it.imageUrl = "https://pdc.princeton.edu/sites/pdc/files/events/new-nba-logo-1.png"
}
insertItemsIntoDb(response)
page++
}
}
}
private fun insertItemsIntoDb(response: Response<AllPlayerData>) {
GlobalScope.launch {
response.body()!!.data!!.forEach {
dao.insert(it)
}
}
}
}
Logic for, If onItemAtEndLoaded get the same itemAtEnd , then do nothing.
var lastItemAtEnd:DataItem? = null
override fun onItemAtEndLoaded(itemAtEnd: DataItem) {
lastItemAtEnd?.timestamp?.apply{
if(itemAtEnd.timestamp==this){
return;
}
}
super.onItemAtEndLoaded(itemAtEnd)
api.getAllPlayer(page).clone().enqueue(createWebserviceCallback())
}
As your page size is 25 so Pagelist config should have setInitialLoadSizeHint as 25 for avoiding looping/unnecessary call of onItemAtEndLoaded method
val config = PagedList.Config.Builder()
.setPageSize(25)
.setInitialLoadSizeHint(25) //same as your page size
.setEnablePlaceholders(false)
.build()
I know it's been long but i just post the solution in case someone need.
you should register an observer for your adapter and listen for onItemRangeInserted event and if the start position of item range is zero just simply scroll adapter to zero position, this make your RecyclerView on first load stay in zero position and by the way you should set setPrefetchDistance value smaller than the setInitialLoadSizeHint.
This is the Java code for adapters observer
adapter.registerAdapterDataObserver(new RecyclerView.AdapterDataObserver() {
#Override
public void onItemRangeInserted(int positionStart, int itemCount) {
super.onItemRangeInserted(positionStart, itemCount);
if(positionStart == 0)
recyclerView.scrollToPosition(positionStart);
}
});
I'm trying to implement Recyclerview in my kotlin code....
And I'm using Retrofit getting data from webservice and plot it into recycler view
MainActivity.class
class MainActivity : AppCompatActivity() {
internal lateinit var jsonApi:MyAPI
private val compositeDisposable = CompositeDisposable()
lateinit var recyclerView: RecyclerView
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
recyclerView = findViewById(R.id.recycler_drivers)
// init API
val retrofitt = RetrofitClient.instance
if (retrofitt != null) {
jsonApi = retrofitt.create(MyAPI::class.java)
}
//View
recyclerView.setHasFixedSize(true)
recyclerView.layoutManager = LinearLayoutManager(this)
fetchData()
}
private fun fetchData() {
compositeDisposable.add(jsonApi.drivers
.subscribeOn(Schedulers.io())
.observeOn(AndroidSchedulers.mainThread())
.subscribe{drivers->displayData(drivers)}
)
}
private fun displayData(drivers: List<Driver>?) {
val adapter = DriverAdapter(this,drivers!!)
recycler_drivers.adapter = adapter
}
}
Adapter.class
class DriverAdapter(internal var contex:Context, internal var driverList:List<Driver>): RecyclerView.Adapter<DriverViewHolder>()
{
override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): DriverViewHolder {
val itemView = LayoutInflater.from(parent.context)
.inflate(R.layout.driver_layout, parent, false)
return DriverViewHolder(itemView)
}
override fun getItemCount(): Int {
return driverList.size
}
override fun onBindViewHolder(holder: DriverViewHolder, position: Int) {
holder.txt_driver_number.text = driverList[position].driver_number
holder.txt_first_name.text = driverList[position].first_name
holder.txt_ph_number.text = driverList[position].ph_number.toString()
}
}
ViewHolder.class
class DriverViewHolder(itemView: View) : RecyclerView.ViewHolder(itemView) {
val txt_driver_number = itemView.txt_driver_number
val txt_first_name = itemView.txt_first_name
val txt_ph_number = itemView.txt_ph_number
}
This is the API interface
interface MyAPI {
#get:GET("data")
val drivers:Observable<List<Driver>>
}
RetrofitClient Object
object RetrofitClient {
private var ourInstance : Retrofit? = null
var instance: Retrofit? = null
get(){
if(ourInstance == null){
ourInstance = Retrofit.Builder()
.baseUrl("http://localhost/BSProject/public/")
.addConverterFactory(GsonConverterFactory.create())
.addCallAdapterFactory(RxJava2CallAdapterFactory.create())
.build()
}
return ourInstance!!
}
}
and this is the Model class which is basically the data coming form my localhost server
class Driver {
var driver_number: String = ""
var first_name: String = ""
var ph_number: Int = 0
}
As you can see I have attached an adapter for Recycleview. so why do I keep getting this error?
I have read other questions related to same problem, but none helps.
Either build the recyclerView inside your displayData()
private fun displayData(drivers: MutableList<Driver>?) {
recyclerView.setHasFixedSize(true)
recyclerView.layoutManager = LinearLayoutManager(this)
val adapter = DriverAdapter(this,drivers!!)
recycler_drivers.adapter = adapter
}
Or do what Gabriele Suggested where you attach your adapter to the recyclerviewin onCreate() and add your response data to your adapter after having made the call. This is the ideal approach
class MainActivity: {
lateinit var driverAdapter: DriverAdapter
protected void onCreate() {
...
recyclerView = findViewById(R.id.recycler_drivers)
recyclerView.setHasFixedSize(true)
recyclerView.layoutManager = LinearLayoutManager(this)
val adapter = DriverAdapter(this)
recycler_drivers.adapter = adapter
}
private fun displayData(drivers: List<Driver>?) {
driverAdapter.setDrivers(drivers)
}
And you'd expose a method in your adapter to set the data setDrivers()
class DriverAdapter(internal var contex:Context):
RecyclerView.Adapter<DriverViewHolder>()
{
val drivers = mutableListOf()
...
fun setDrivers(drivers: MutableList<Driver>) {
this.drivers = drivers
notifyDataSetChanged()
}
}
This will get rid of your No adapter attached; skipping layout :RecyclerView error
I think you are seeing this issue because of the asynchronous nature of querying the web service through retrofit. You don't actually assign the RecyclerView.Adapter until after onCreate exits.
Try changing the visiblility of the RecyclerView to Gone until the adapter is applied in displayData, then set it to Visible