//刷新表格3种形式
//1.全部刷新刷新整个表
[table reloadData];
//2.局部刷新Sections:要刷新的区索引的集合
NSIndexSet *set = [NSIndexSet indexSetWithIndex:btn.tag-100];
//局部刷新区(NSIndexSet *)sections要刷新的区索引的集合
[table reloadSections:set withRowAnimation:UITableViewRowAnimationFade];
//3.局部刷新行(row)
NSIndexPath * path = [NSIndexPath indexPathForRow:2 inSection:0];
NSArray * array = @[path];
[table reloadRowsAtIndexPaths:array withRowAnimation:UITableViewRowAnimationFade];
