cell 刷新

//一个section刷新    

NSIndexSet *indexSet=[[NSIndexSet alloc]initWithIndex:2];    

[tableview reloadSections:indexSet withRowAnimation:UITableViewRowAnimationAutomatic];    

//一个cell刷新    

NSIndexPath *indexPath=[NSIndexPath indexPathForRow:3 inSection:0];    

[tableView reloadRowsAtIndexPaths:[NSArray arrayWithObjects:indexPath,nil] withRowAnimation:UITableViewRowAnimationNone];