RecyclerView滑动距离计算

来源：互联网发布：ipad 看图软件编辑：程序博客网时间：2024/06/03 16:01

最近在写关于RecyclerView滑动到最底部时，给出一个判断，是否到达最底部。但不知道为什么，总是得不到ScrollY，一直为0。没办法，只能去网上找一些相关资料。但因为是实习生，自定义RecycleView这些很多都看不懂，只能去找最简单的办法。下面就是我找到的办法，在这里记录一下。非常感谢知乎用户－张宇给的解法。

废话不多说，代码贴上：

    /**     * 还能向下滑动多少     */    private int getDistance(){        LinearLayoutManager layoutManager = (LinearLayoutManager) mRecyclerView.getLayoutManager();        View firstVisibItem = mRecyclerView.getChildAt(0);        int firstItemPosition = layoutManager.findFirstVisibleItemPosition();        int itemCount = layoutManager.getItemCount();        int recycleViewHeight = mRecyclerView.getHeight();        int itemHeight = firstVisibItem.getHeight();        int firstItemBottom = layoutManager.getDecoratedBottom(firstVisibItem);        return (itemCount - firstItemPosition - 1)* itemHeight - recycleViewHeight+firstItemBottom;    }

当前的getDistance()就是剩余的距离。

    /**     * 已滑动的距离     */    private int getDistance(){        LinearLayoutManager layoutManager = (LinearLayoutManager) mRecyclerView.getLayoutManager();        View firstVisibItem = mRecyclerView.getChildAt(0);        int firstItemPosition = layoutManager.findFirstVisibleItemPosition();        int itemCount = layoutManager.getItemCount();        int recycleViewHeight = mRecyclerView.getHeight();        int itemHeight = firstVisibItem.getHeight();        int firstItemBottom = layoutManager.getDecoratedBottom(firstVisibItem);        return (firstItemPosition + 1)*itemHeight - firstItemBottom;    }

当前的getDistance()就是已经滑动的距离了。然后我根据这个人的算法，判断自己有没有滑倒最底部了。

    /**     * 获取RecyclerView滚动位置     */    private int getDistance(){        LinearLayoutManager layoutManager = (LinearLayoutManager) mRecyclerView.getLayoutManager();        View firstVisibItem = mRecyclerView.getChildAt(0);        int firstItemPosition = layoutManager.findFirstVisibleItemPosition();        int itemCount = layoutManager.getItemCount();        int recycleViewHeight = mRecyclerView.getHeight();        int itemHeight = firstVisibItem.getHeight();        int firstItemBottom = layoutManager.getDecoratedBottom(firstVisibItem);        return (itemCount - firstItemPosition - 1)* itemHeight - recycleViewHeight;    }

这样当getDistance()等于0时，我就知道已经滑动到最底部了。如果你们RecyclerView上面有间距，自己看一下getDistance()等于多少。

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