在實際處理業務的時候經常會需要判斷列表是否到底部或者頂部，現在基本都是用RecyclerView來做列表，這裡SDK提供了一個方法非常簡單就可以解決，

// 垂直方向的判斷

/**
     * Check if this view can be scrolled vertically in a certain direction.
     *
     * @param direction Negative to check scrolling up, positive to check scrolling down.
     * @return true if this view can be scrolled in the specified direction, false otherwise.
     */
    public boolean canScrollVertically(int direction) {
        final int offset = computeVerticalScrollOffset();
        final int range = computeVerticalScrollRange() - computeVerticalScrollExtent();
        if (range == 0) return false;
        if (direction < 0) {
            return offset > 0;
        } else {
            return offset < range - 1;
        }
    }
 

computeVerticalScrollOffset：計算控制元件垂直方向的偏移值，

computeVerticalScrollExtent：計算控制元件可視的區域，

computeVerticalScrollRange：計算控制元件垂直方向的滾動範圍

// 水平方向的判斷

/**
     * Check if this view can be scrolled horizontally in a certain direction.
     *
     * @param direction Negative to check scrolling left, positive to check scrolling right.
     * @return true if this view can be scrolled in the specified direction, false otherwise.
     */
    public boolean canScrollHorizontally(int direction) {
        final int offset = computeHorizontalScrollOffset();
        final int range = computeHorizontalScrollRange() - computeHorizontalScrollExtent();
        if (range == 0) return false;
        if (direction < 0) {
            return offset > 0;
        } else {
            return offset < range - 1;
        }
    }
 

比如：判斷是否滑動到底部， recyclerView.canScrollVertically(1);返回false表示不能往上滑動，即代表到底部了；

            判斷是否滑動到頂部， recyclerView.canScrollVertically(-1);返回false表示不能往下滑動，即代表到頂部了；

其他的方向的判斷同理，在這裡做個記錄