主要内容
1. 和ListView区别
2. 重写方法
3. 点击事件
https://www.jianshu.com/p/5f876361e671
5. 数据更新
6. Item添加和删除
https://www.jianshu.com/p/9806917d3d99
7.加载不同ItemView
8. 底部刷新
https://blog.csdn.net/ccpat/article/details/70038107
https://juejin.im/post/58ef5588ac502e006c169a08
https://blog.csdn.net/ThugKd/article/details/79220355
