Try and fix Epoxy crashing

Works around airbnb/epoxy#567

Author: Chris Banes

app/src/main/java/app/tivi/home/library/LibraryViewModel.kt

@@ -50,7 +50,7 @@ import java.util.concurrent.TimeUnit
 
 class LibraryViewModel @AssistedInject constructor(
     @Assisted initialState: LibraryViewState,
-    schedulers: AppRxSchedulers,
+    private val schedulers: AppRxSchedulers,
     private val updateWatchedShows: UpdateWatchedShows,
     private val syncFollowedShows: SyncFollowedShows,
     private val traktManager: TraktManager,
@@ -119,19 +119,15 @@ class LibraryViewModel @AssistedInject constructor(
     }
 
     private fun <T : EntryWithShow<*>> dataSourceToObservable(f: DataSource.Factory<Int, T>): Observable<PagedList<T>> {
-        return RxPagedListBuilder(f, PAGING_CONFIG).setBoundaryCallback(object : PagedList.BoundaryCallback<T>() {
-            override fun onZeroItemsLoaded() {
-                setState { copy(isEmpty = true) }
-            }
-
-            override fun onItemAtEndLoaded(itemAtEnd: T) {
-                setState { copy(isEmpty = false) }
-            }
-
-            override fun onItemAtFrontLoaded(itemAtFront: T) {
-                setState { copy(isEmpty = false) }
-            }
-        }).buildObservable()
+        return RxPagedListBuilder(f, PAGING_CONFIG)
+                .setBoundaryCallback(object : PagedList.BoundaryCallback<T>() {
+                    override fun onZeroItemsLoaded() = setState { copy(isEmpty = true) }
+                    override fun onItemAtEndLoaded(itemAtEnd: T) = setState { copy(isEmpty = false) }
+                    override fun onItemAtFrontLoaded(itemAtFront: T) = setState { copy(isEmpty = false) }
+                })
+                .setFetchScheduler(schedulers.io)
+                .setNotifyScheduler(schedulers.main)
+                .buildObservable()
     }
 
     fun refresh() {

app/src/main/java/app/tivi/home/library/LibraryWatchedEpoxyController.kt

@@ -39,7 +39,8 @@ class LibraryWatchedEpoxyController(
                 spanSizeOverride(TotalSpanOverride)
             }
         } else {
-            super.addModels(models)
+            // Need to use filterNotNull() due to https://github.com/airbnb/epoxy/issues/567
+            super.addModels(models.filterNotNull())
         }
     }
 

app/src/main/java/app/tivi/util/EntryGridEpoxyController.kt

@@ -50,9 +50,13 @@ open class EntryGridEpoxyController<LI : EntryWithShow<out Entry>> : PagedListEp
         fun onItemClicked(item: LI)
     }
 
+    @Suppress("UselessCallOnCollection")
     override fun addModels(models: List<EpoxyModel<*>>) {
-        if (models.isNotEmpty()) {
-            super.addModels(models)
+        // Need to do this due to https://github.com/airbnb/epoxy/issues/567
+        val modelsFiltered = models.filterNotNull()
+
+        if (modelsFiltered.isNotEmpty()) {
+            super.addModels(modelsFiltered)
         } else {
             emptyState {
                 id("item_placeholder")

app/src/main/java/app/tivi/util/EntryViewModel.kt

@@ -32,9 +32,9 @@ import io.reactivex.subjects.BehaviorSubject
 import kotlinx.coroutines.launch
 
 abstract class EntryViewModel<LI : EntryWithShow<out Entry>>(
-    private val schedulers: AppRxSchedulers,
+    schedulers: AppRxSchedulers,
     private val dispatchers: AppCoroutineDispatchers,
-    private val dataSource: DataSource.Factory<Int, LI>,
+    dataSource: DataSource.Factory<Int, LI>,
     tmdbManager: TmdbManager,
     private val logger: Logger,
     private val pageSize: Int = 21
@@ -54,10 +54,10 @@ abstract class EntryViewModel<LI : EntryWithShow<out Entry>>(
                     tmdbManager.imageProviderFlowable,
                     RxPagedListBuilder<Int, LI>(dataSource, pageListConfig)
                             .setBoundaryCallback(object : PagedList.BoundaryCallback<LI>() {
-                                override fun onItemAtEndLoaded(itemAtEnd: LI) {
-                                    onListScrolledToEnd()
-                                }
+                                override fun onItemAtEndLoaded(itemAtEnd: LI) = onListScrolledToEnd()
                             })
+                            .setFetchScheduler(schedulers.io)
+                            .setNotifyScheduler(schedulers.main)
                             .buildFlowable(BackpressureStrategy.LATEST)
                             .distinctUntilChanged(),
                     ::EntryViewState