BaseAdapter.notifyDataSetChanged();
mScroller.startScroll(oldX, 0, dx, 0);

BaseAdapter.notifyDataSetChanged();
 new Handler().postDelayed(new Runnable() {
      @Override
              public void run() {
                 mScroller.startScroll(oldX, 0, dx, 0);
                //write scroll code here
               }
       },50);  //scroll after 50ms

@Override
public void notifyDataSetChanged()
{
    super.notifyDataSetChanged();

    parentGlobal.setSelection(this.getCount() - 1);  //This is how we start Activity fully scrolled to bottom
}

lv_main = (ListView) findViewById(R.id.listView_conversation);
    adapter_main = new Adapter_Conversation(ConversationActivity.this, R.layout.layout_list_conversation,
            list_main_UI, lv_main, main_list_item_margin_px);
    lv_main.setAdapter(adapter_main);

public Adapter_Conversation(AppCompatActivity activity, @LayoutRes int resource,
                            ArrayList<Adapter_GetSet_Conversation> list_conversation, ListView lv_main,
                            int item_margin_px)