Our ViewModel for Kitsu Screen

KitsuViewModel.kt

class KitsuViewModel(app: Application) : AndroidViewModel(app) {
    private var allKitsuLiveData: LiveData<PagedList<KitsuItem>>? = null
    val allKitsu: LiveData<PagedList<KitsuItem>>
        get() {
            if (null == allKitsuLiveData) {
                allKitsuLiveData = KitsuMediaPagedListProvider.allKitsu().create(0,
                        PagedList.Config.Builder()
                                .setPageSize(PAGED_LIST_PAGE_SIZE)
                                .setInitialLoadSizeHint(PAGED_LIST_PAGE_SIZE)
                                .setEnablePlaceholders(PAGED_LIST_ENABLE_PLACEHOLDERS)
                                .build())!!
            }
            return allKitsuLiveData ?: throw AssertionError("Check your threads ...")
        }

    fun setQueryFilter(queryFilter: String) {
        KitsuMediaPagedListProvider.setQueryFilter(queryFilter)
        allKitsuLiveData = null // invalidate
    }

    companion object {
        private const val PAGED_LIST_PAGE_SIZE = 20
        private const val PAGED_LIST_ENABLE_PLACEHOLDERS = false
    }
}