RecyclerView 踩坑

一、RecyclerView设置拖动后怎么监听拖动的开始和结束

 ItemTouchHelper helper = new ItemTouchHelper(new ItemTouchHelper.Callback() {
            @Override
            public int getMovementFlags(RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder) {
                //首先回调的方法 返回int表示是否监听该方向
                int dragFlags = ItemTouchHelper.UP | ItemTouchHelper.DOWN | ItemTouchHelper.LEFT | ItemTouchHelper.RIGHT;//拖拽
//                int swipeFlags = ItemTouchHelper.UP | ItemTouchHelper.DOWN;//侧滑删除
                return makeMovementFlags(dragFlags, -1);
            }
            @Override
            public boolean onMove(RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder, RecyclerView.ViewHolder target) {
                //滑动事件
                Collections.swap(mList, viewHolder.getAdapterPosition(), target.getAdapterPosition());
                mAdapter.notifyItemMoved(viewHolder.getAdapterPosition(), target.getAdapterPosition());
                return true;
            }
 
            @Override
            public void onSelectedChanged(RecyclerView.ViewHolder viewHolder, int actionState) {
 
                if (viewHolder == null) {
//                   onMoveEnd(); //拖动结束
                    ToastUtil.showShort(mContext,"拖动结束");
                    mAdapter.notifyDataSetChanged();
                } else {
//                   onMoveStart();  //拖动开始
                }
                super.onSelectedChanged(viewHolder, actionState);
            }
 
            @Override
            public void onSwiped(final RecyclerView.ViewHolder viewHolder, int direction) {
                //侧滑事件
//                onItemDelete(viewHolder.itemView, viewHolder.getAdapterPosition());
//                mCAdapter.notifyItemRemoved(viewHolder.getAdapterPosition());
            }
            @Override
            public boolean isLongPressDragEnabled() {
                //是否可拖拽
                return true;
            }
            @Override
            public boolean isItemViewSwipeEnabled() {
                //是否可以删除
                return false;
            }
        });
        helper.attachToRecyclerView(mRvEdtSort); //设置给RecyleView

重写 onSelectedChanged 方法，并且判断是否拖动的开始和结束。

二、RecyclerView加载更多用notifyDataSetChanged()刷新图片闪烁