I am implementing swipe to refresh with the PagingLibrary 3.0.
My repository returns a flow of PagingData<Item> which is then exposed as LiveData by a viewmodel.
Repository
override fun getItems(): Flow<PagingData<Item>> {
val pagingConfig = PagingConfig(pageSize = 20, enablePlaceholders = false)
val pager = Pager(pagingConfig) {
IndexedPagingSource(remoteDataSource)
}
return pager.flow
}
ViewModel
val itemsStream: LiveData<PagingData<Item>> = repository.getItems()
.asLiveData()
.cachedIn(viewModelScope)
Fragment
private fun FragmentItemListBinding.bindView() {
list.adapter = adapter
list.layoutManager = LinearLayoutManager(context)
swipeRefresh.setOnRefreshListener { onRefresh() }
adapter.loadStateFlow
.onEach { resolveLoadState(it) }
.launchIn(viewLifecycleOwner.lifecycleScope)
viewModel.itemsStream.observeWithViewLifecycleOwner {
adapter.submitData(viewLifecycleOwner.lifecycle, it)
}
}
private fun onRefresh() {
adapter.refresh()
}
private fun FragmentItemListBinding.resolveLoadState(loadState: CombinedLoadStates) {
val adapterEmpty = adapter.itemCount < 1
swipeRefresh.isRefreshing = loadState.refresh is LoadState.Loading && !adapterEmpty
// resolve all other states here...
}
The problem is that while the refresh is in progress, the paging stops working (and any ongoing requests are cancelled while the UI stays the same - talking about you LoadStateFooter). And it stops until the refresh succeeds, which includes failure.
If I don't have any data, I simply display an error screen. But in this case I want to see the previous items and continue paging even after error.
Is there a way to continue paging in the case of a refresh error?
The official architecture components sample for paging has the same behavior.
