How to tell RecyclerView to start at specific item position

Question

I want my RecyclerView with LinearLayoutManager to show up with scroll position at specific item after adapter got updated. (not first/last position) Means the at first (re-)lay

Answer 1

None of the methods above worked for me. I did the following using ViewTreeObserver that is triggered once its children have been added/changed visibility.

recyclerView.apply {
   adapter = ...
   layoutManager = ...

   val itemCount = adapter?.itemCount ?: 0
   if(itemCount > 1) {
      viewTreeObserver.addOnGlobalLayoutListener(object: ViewTreeObserver.OnGlobalLayoutListener {
      override fun onGlobalLayout() {
         viewTreeObserver.removeOnGlobalLayoutListener(this)
         (layoutManager as? LinearLayoutManager)?.scrollToPosition(#PositionToStartAt)
      }
   }
}

Go ahead and set #PositionToStartAt to a specific value. You can also ensure that the RecyclerView initial position setting gets triggered once a specific number of children have been laid out to ensure it is set correctly.

if(recyclerView.childCount() > #PositionCheck) {
   viewTreeObserver.removeOnGlobalLayoutListener(this)
   (layoutManager as? LinearLayoutManager)?.scrollToPosition(#PositionToStartAt)
}