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class MyDatasource( private val queryMap: HashMap<String, String>) : ItemKeyedDataSource<String, Order>() { private val compositeDisposable: CompositeDisposable by lazy { CompositeDisposable() } override fun loadInitial(params: LoadInitialParams<String>, callback: LoadInitialCallback<Order>) { compositeDisposable.add( MyService.getService().fetchData(queryMap) .subscribeOn(Schedulers.io()) .observeOn(AndroidSchedulers.mainThread()) .subscribeWith(object : DisposableObserver<OrdersResponse>() { override fun onNext(orders: OrdersResponse) { callback.onResult(orders.data) } override fun onError(e: Throwable) { e.printStackTrace() } override fun onComplete() { } }) ) } override fun loadBefore(params: LoadParams<String>, callback: LoadCallback<Order>) { // do nothing } override fun loadAfter(params: LoadParams<String>, callback: LoadCallback<Order>) { queryMap["offsetOrderId"] = params.key compositeDisposable.add( MyService.getService().fetchData(queryMap) .subscribeOn(Schedulers.io()) .observeOn(AndroidSchedulers.mainThread()) .subscribeWith(object : DisposableObserver<OrdersResponse>() { override fun onNext(orders: OrdersResponse) { callback.onResult(orders.data) } override fun onError(e: Throwable) { } override fun onComplete() { } }) ) } override fun getKey(item: Order): String { return item.orderId } 

}

I build pagedlist in my viewmodel

class MyViewModel() : ViewModel() {   private var myPagingConfig: PagedList.Config? = null var dataList: LiveData<PagedList<Order>>? = null fun getOrders(params: HashMap<String, String>) { if (myPagingConfig == null) { myPagingConfig = PagedList.Config.Builder() .setPageSize(LIMIT) .setPrefetchDistance(10) .setEnablePlaceholders(false) .build() } dataList = LivePagedListBuilder(MyDataFactory( MyDatasource(params)), myPagingConfig!!) .setInitialLoadKey(null) .setFetchExecutor(Executors.newFixedThreadPool(5)) .build() } 

}

class MyDatasource(  private val queryMap: HashMap<String, String>) : ItemKeyedDataSource<String, Order>() {  private val compositeDisposable: CompositeDisposable by lazy { CompositeDisposable() }  override fun loadInitial(params: LoadInitialParams<String>, callback: LoadInitialCallback<Order>) {   compositeDisposable.add(   MyService.getService().fetchData(queryMap)   .subscribeOn(Schedulers.io())   .observeOn(AndroidSchedulers.mainThread())   .subscribeWith(object : DisposableObserver<OrdersResponse>() {   override fun onNext(orders: OrdersResponse) {   callback.onResult(orders.data)   }   override fun onError(e: Throwable) {   e.printStackTrace()   }   override fun onComplete() {   }   })   )  }  override fun loadBefore(params: LoadParams<String>, callback: LoadCallback<Order>) {   // do nothing  }  override fun loadAfter(params: LoadParams<String>, callback: LoadCallback<Order>) {   queryMap["offsetOrderId"] = params.key   compositeDisposable.add(   MyService.getService().fetchData(queryMap)   .subscribeOn(Schedulers.io())   .observeOn(AndroidSchedulers.mainThread())   .subscribeWith(object : DisposableObserver<OrdersResponse>() {   override fun onNext(orders: OrdersResponse) {   callback.onResult(orders.data)   }   override fun onError(e: Throwable) {   }   override fun onComplete() {   }   })   )  }  override fun getKey(item: Order): String {   return item.orderId  } } 

I build pagedlist in my viewmodel

class MyViewModel() : ViewModel() {  private var myPagingConfig: PagedList.Config? = null  var dataList: LiveData<PagedList<Order>>? = null  fun getOrders(params: HashMap<String, String>) {     if (myPagingConfig == null) {   myPagingConfig = PagedList.Config.Builder()   .setPageSize(LIMIT)   .setPrefetchDistance(10)   .setEnablePlaceholders(false)   .build()   }   dataList = LivePagedListBuilder(MyDataFactory(   MyDatasource(params)), myPagingConfig!!)   .setInitialLoadKey(null)   .setFetchExecutor(Executors.newFixedThreadPool(5))   .build()  } } 

I use paging library from Android Architecture Components.

However, when I observe dataList in my activity, it sometimes (most of the times) returns empty list, while in logcat i see that i had fetched data successfully. callback.onResult is invoked after it returns empty list, but observer never gets notified again.

I am using a paging library from Android Architecture Components.

However, when I observe the dataList in my activity, it sometimes (most of the times) returns an empty list, while in logcat I see that I had fetched data successfully. callback.onResult is invoked after it returns an empty list, but observer never gets notified again.