code: public static void bindDragHandle(final RecyclerView.ViewHolder holder, final IExtendedDraggable item) {
          // if necessary, init the drag handle, which will start the drag when touched
          if (item.getTouchHelper() != null && item.getDragView(holder) != null) {
              item.getDragView(holder).setOnTouchListener(new View.OnTouchListener() {
                  @Override
                  public boolean onTouch(View v, MotionEvent event) {
                      if (MotionEventCompat.getActionMasked(event) == MotionEvent.ACTION_DOWN) {
                          if (item.isDraggable())
                              item.getTouchHelper().startDrag(holder);
                      }
                      return false;
                  }
              });
          }
      }
docs: this functions binds the view's touch listener to start the drag via the touch helper...
  
  @param holder the view holder
  @param holder the item