I'm using paging 3 to paginate my items and then show them in recycler view. but there's a time that the first item change. for example, consider the situation below:
item A
item B
item C
after a while, for some reason, data gets update and list order changes to like bellow:
item B
item A
item C
my problem is:
recycler view stays exactly in its last position. I mean when update apply, item B will go to the first position but recycler view won't scroll to the top, it just states pointing to item A, and the user won't notify that item B has changed,
how can I set that recycler view scroll automatically just when the first item changed?
here is part of my adapter:
class TicketListAdapter : PagingDataAdapter<TicketListModel, TicketListAdapter.ViewHolder>(
diffCallback = object : DiffUtil.ItemCallback<TicketListModel>() {
override fun areItemsTheSame(oldItem: TicketListModel, newItem: TicketListModel): Boolean {
return oldItem.ticket_id == newItem.ticket_id
}
override fun areContentsTheSame(
oldItem: TicketListModel,
newItem: TicketListModel
): Boolean {
return oldItem == newItem
}
}
){
override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): ViewHolder {
val view = LayoutInflater.from(parent.context)
.inflate(R.layout.ticket_list_item_model, parent, false)
return ViewHolder(view)
}
override fun onBindViewHolder(holder: ViewHolder, position: Int)= holder.bind(getItem(position))
and here shows how I use my recycler view and data:
binding.recyclerView.apply {
this.adapter = adapter
this.layoutManager = LinearLayoutManager(requireContext())
}
viewModel.tickets.observe(viewLifecycleOwner, {
viewLifecycleOwner.lifecycleScope.launch {
adapter.submitData(it)
}
})
I also try that set observer but it didn't work:
adapter.registerAdapterDataObserver(object : RecyclerView.AdapterDataObserver() {
override fun onChanged() {
super.onChanged()
if (adapter.getItemId(0) != firstItemId) {
binding.recyclerView.smoothScrollToPosition(0)
firstItemId = adapter.getItemId(0)
}
}
the firstItemId is initialized with value -1;
