recyclerview.scrollToPosition(adapterarray.size()-1) 导致项目以相反的顺序出现

Question

I'm using Android Studio.

My recylview and its adapter works very well. My recyclerview can only 6 rows because of its design. So the items from 1 to 6 are showing perfectly. When the 7th item added, it stays out of recyclerView borders so I should manualy scroll it to see the 7th line. I decided to make it autoscroll to the last item line of the recyclerView. That means last 6 lines (say there is 10 items, so the lines 5,6,7,8,9,10 should be shown automatically.

In order to accomplish this, I have added the following line just after the line recyclerview.setAdapter(adapter);

recyclerView.scrolltoposition(adapterarray.size()-1)

But now, the items are showing in reverse order. The last item is at the top of the recylerVeiw. It seems that scrolltoposition sorts not only recyclerVievitself but also adapter.

How can I simply perform an auto scroll after adding new items in recyclerView if it is more than6 lines?

Answer 1

Try something like that:

recyclerView.addOnLayoutChangeListener(new View.OnLayoutChangeListener() {
            @Override
            public void onLayoutChange(View v, int left, int top, int right, int bottom, int oldLeft, int oldTop, int oldRight, int oldBottom) {
                if (bottom < oldBottom) {
                    recyclerView.postDelayed(new Runnable() {
                        @Override
                        public void run() {
                  recyclerView.smoothScrollToPosition(adapter.getItemCount());
                        }
                    }, 100);
                }
            }
});