Flutter 下拉刷新、上拉加载flutter_easyrefresh 自定义样式

  EasyRefresh(
    header: MaterialHeader(),
    footer: MaterialFooter(),
    child: ListView(),
    ....
  )
  // 全局设置
  EasyRefresh.defaultHeaderBuilder = () => ClassicHeader();
  EasyRefresh.defaultFooterBuilder = () => ClassicFooter();