当第一项更改时，RecyclerView 滚动到更改的项目位置

Question

I have a RecyclerView with a checkbox for every item. When checkbox pressed it is moved to the bottom of the list. When i check any item besides the first one everything is OK but if i check the first one, it auto-scroll to the new item location.

I redesigned the adapter using a recent codelab but still the same issue

class ItemsAdapter(val clickListener: ItemAdapterListener):
    ListAdapter<UiQueryItem<Item>, ItemsAdapter.ViewHolder>(asyncDifferConfig) {

    companion object {
        private val diffCallback = object : UiQueryItemDiffCallback<Item>() {}
        private val executors = AppExecutors()
        private val asyncDifferConfig =
            AsyncDifferConfig.Builder<UiQueryItem<Item>>(diffCallback)
                .setBackgroundThreadExecutor(executors.cpuExecutorService)
                .build()
    }

    override fun onBindViewHolder(holder: ViewHolder, position: Int) {
        val item = getItem(position)
        holder.bind(item,clickListener)
    }

    override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): ViewHolder {
        return ViewHolder.from(parent)
    }

    class ViewHolder private constructor(val binding: ListItemBinding): RecyclerView.ViewHolder(binding.root){

        fun bind(item: UiQueryItem<Item>, clickListener: ItemAdapterListener) {
            binding.item = item.item
            binding.clickListener = clickListener
            binding.isSelected = item.isFlag1
            binding.executePendingBindings()
        }

        companion object {
            fun from(parent: ViewGroup): ViewHolder {
                val layoutInflater = LayoutInflater.from(parent.context)
                val binding = ListItemBinding.inflate(layoutInflater, parent, false)
                return ViewHolder(binding)
            }
        }
    }
}

Answer 1

I think i found a workaround.

I noticed the next github issue solution:

Automatic scrolling when new data set #224

It did not work in my case but after tweaking a bit i found an answer. Please note that it is only a workaround and might make some bugs if you are trying to implement your own auto-scroll solution. The Workaround simply checkes if an item changed position from first place and if so, gets back to first position

Also note that @elihart is suggesting other solutions (check the link)

private val dataObserver = object : RecyclerView.AdapterDataObserver() {
        override fun onItemRangeMoved(fromPosition: Int, toPosition: Int, itemCount: Int) {
            super.onItemRangeMoved(fromPosition, toPosition, itemCount)
            if (fromPosition == 0) {
                binding.itemRv.scrollToPosition(0)
            }
        }
    }

override fun onResume() {
    super.onResume()
    adapter.registerAdapterDataObserver(dataObserver)
}

override fun onPause() {
    super.onPause()
    adapter.unregisterAdapterDataObserver(dataObserver)
}