danielgomezrico
/ ScrollToTopDataObserver.kt
Created
July 15, 2016 04:00
Android / Kotlin - Scroll recycler view automatically based on initial items and scroll to bottom on new items (like a chat room)
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| class ScrollToTopDataObserver(val layoutManager: LinearLayoutManager, | |
| val recyclerView: RecyclerView) | |
| : RecyclerView.AdapterDataObserver() { | |
| override fun onItemRangeInserted(positionStart: Int, itemCount: Int) { | |
| super.onItemRangeInserted(positionStart, itemCount) | |
| val lastVisiblePosition = layoutManager.findLastCompletelyVisibleItemPosition() | |
| // If the recycler view is initially being loaded or the user is at the bottom of the | |
| // list, scroll to the bottom of the list to show the newly added message. | |
| if (lastVisiblePosition == -1 || positionStart >= itemCount - 1 && lastVisiblePosition == positionStart - 1) { |