ItemTouchHelper - The drop is forced after the first jumped line

Question

I am using ItemTouchHelper and ItemTouchHelper.SimpleCallback to allow the user to reorder a vertical list Recycler View.

The drag and drop works but the drop is forced after the first jumped line even though I don't leave up my finger from the dragged cell.

Please find below the SimpleCallback :

private void initSwipeAndDrap() {

    ItemTouchHelper.SimpleCallback simpleItemTouchCallback =
            new ItemTouchHelper.SimpleCallback(
                    ItemTouchHelper.UP | ItemTouchHelper.DOWN,
                    0) {

                //========== Swipe (Not used) ==============

                @Override
                public void onSwiped(RecyclerView.ViewHolder viewHolder, int direction) {
                }


                //========== Drag ==============

                @Override
                public boolean onMove(RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder, RecyclerView.ViewHolder target) {

                    int fromPosition = viewHolder.getAdapterPosition();
                    int toPosition = target.getAdapterPosition();

                    Podcast podcast = rva.podcasts.remove(fromPosition);
                    rva.podcasts.add(toPosition, podcast);
                    act.dmo.updatePodcastsListPosition();
                    act.dmo.notifyDataSetChangedPodcast();

                    return true;
                }

                @Override
                public boolean isLongPressDragEnabled() {
                    return false;
                }


            };

    itemTouchHelper = new ItemTouchHelper(simpleItemTouchCallback);
    itemTouchHelper.attachToRecyclerView(rv);
}

score 5 · Accepted Answer · answered Aug 03 '16 at 07:50

5

Replacing notifyDataSetChanged() by notifyItemMoved() in onMove() method fixed my problem.

Which supprised me as I thought that onMove() was called after the drop. In fact, it has an effect on the drop itself.

answered Aug 03 '16 at 07:50

u2gilles

4,628
4
35
59

I came across the problem. Thanks for posting the solution. – Malko Aug 10 '16 at 07:37
1

For those still not worked: [Why does my RecyclerView with ItemTouchHelper stop dragging after only one item, after overriding getItemViewType()?](https://stackoverflow.com/questions/39996110/why-does-my-recyclerview-with-itemtouchhelper-stop-dragging-after-only-one-item?rq=1) – nyconing Jan 09 '18 at 14:44

score 3 · Answer 2 · answered Nov 30 '18 at 17:02

3

For those having the snaping problem when you move an element, if you are using this override

   @Override
    public int getItemViewType(int position) {
        return position;
    }

Just delete it from your adapter and it will work just fine

answered Nov 30 '18 at 17:02

Gastón Saillén

9,076
4
39
58

ItemTouchHelper - The drop is forced after the first jumped line

2 Answers2

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