定义分页，每页的总数，定义首页，尾页，步长等，然后提交给前台做处理，前台会根据相应的获取值来实现效果。分析，考虑，添加，修改，步长增值，后退减值。-Custom paging, the total number of each page, define the Home, End, step length, etc., and then submitted to the foreground is doing, according to the front desk to get the app