CODEWITHSUNDEEP
androidandroid-recyclerview
dragoon
dragoon

Reputation: 5743

RecyclerView with SnapHelper, item is not snapped after scrollToPosition

I have a RecyclerView in my activity and a LinearSnapHelper attached to it:

TimePickerAdapter timePickerAdapter = new TimePickerAdapter(hours);
recyclerView = (RecyclerView) root.findViewById(R.id.recycler_view);

final SnapHelper snapHelper = new LinearSnapHelper();
snapHelper.attachToRecyclerView(recyclerView);

The problem is that when I want to initially scroll to a specific item, the snap helper is not being triggered to attach the item (see the image):

recyclerView.getLayoutManager().scrollToPosition(timePickerAdapter.getCurrentPosition());

When I scroll with my hand it starts to work as expected. Any solutions to this?

enter image description here

Upvotes: 7

Views: 4881

Answers (3)

Dmitry Kopytov
Dmitry Kopytov

Reputation: 361

If items have the same width and space between them also the same you can use this for initial scroll

recyclerView.apply {
   post {
       val dx = initialPosition * (itemWidth + itemSpace)
       scrollBy(dx, 0)
   }
}

Upvotes: 0

Samuel
Samuel

Reputation: 231

SnapHelper rely on RecyclerView.OnFlingListener#onFling() or RecyclerView.OnScrollListener#onScrollStateChanged(recyclerView, RecyclerView.SCROLL_STATE_IDLE) to trigger snap action.

But scrollToPosition() will not tigger above callback. You can invoke smoothScrollBy(1, 0) after scrollToPosition() to trigger SnapHelper to scroll.

Upvotes: 14

Katharina
Katharina

Reputation: 1642

I just encountered the same issue - for me using recyclerView.smoothScrollToPosition(pos) instead of recyclerView.scrollToPosition(pos) did the trick

Upvotes: 0

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