RecyclerView实现拖拽及滑动

版权声明：本文为博主原创文章，未经博主允许不得转载。 https://blog.csdn.net/xiaoshuxgh/article/details/85624239

网上关于Recycleview实现拖拽的文章很多，在这就不做过多描述，直接上代码：

mItemTouchHelper = new ItemTouchHelper(new ItemTouchHelper.Callback() {
    /**
     * 是否处理滑动事件 以及拖拽和滑动的方向 如果是列表类型的RecyclerView的只存在UP和DOWN，如果是网格类RecyclerView则还应该多有LEFT和RIGHT
     * @param recyclerView
     * @param viewHolder
     * @return
     */
    @Override
    public int getMovementFlags(RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder) {
        if (recyclerView.getLayoutManager() instanceof GridLayoutManager) {
            final int dragFlags = ItemTouchHelper.UP | ItemTouchHelper.DOWN |
                    ItemTouchHelper.LEFT | ItemTouchHelper.RIGHT;
            final int swipeFlags = 0;
            return makeMovementFlags(dragFlags, swipeFlags);
        } else {
            final int dragFlags = ItemTouchHelper.UP | ItemTouchHelper.DOWN;
            final int swipeFlags = 0;
            return makeMovementFlags(dragFlags, swipeFlags);
        }
    }

    @Override
    public boolean onMove(RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder, RecyclerView.ViewHolder target) {
        //得到当拖拽的viewHolder的Position
        int fromPosition = viewHolder.getAdapterPosition();
        //拿到当前拖拽到的item的viewHolder
        int toPosition = target.getAdapterPosition();
        if (fromPosition < toPosition) {
            for (int i = fromPosition; i < toPosition; i++) {
                Collections.swap(showBean.getData(), i, i + 1);
            }
        } else {
            for (int i = fromPosition; i > toPosition; i--) {
                Collections.swap(showBean.getData(), i, i - 1);
            }
        }
        showRvAdapter.notifyItemMoved(fromPosition, toPosition);
        return true;
    }

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

    /**
     * 重写拖拽可用
     * @return
     */
    @Override
    public boolean isLongPressDragEnabled() {
        return false;
    }

    /**
     * 长按选中Item的时候开始调用
     *
     * @param viewHolder
     * @param actionState
     */
    @Override
    public void onSelectedChanged(RecyclerView.ViewHolder viewHolder, int actionState) {
        if (actionState != ItemTouchHelper.ACTION_STATE_IDLE) {
            viewHolder.itemView.setBackgroundColor(Color.LTGRAY);
        }
        super.onSelectedChanged(viewHolder, actionState);
    }

    /**
     * 手指松开的时候还原
     * @param recyclerView
     * @param viewHolder
     */
    @Override
    public void clearView(RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder) {
        super.clearView(recyclerView, viewHolder);
        viewHolder.itemView.setBackgroundColor(0);
    }
});
mItemTouchHelper.attachToRecyclerView(tagdragView);

在要准备拖拽的控件的事件里面设置：
mItemTouchHelper.startDrag(addViewHolder);