思路：
通过获取textfield的父类来判定选中的是哪一行
-(BOOL)textFieldShouldBeginEditing:(UITextField *)textField{
NSIndexPath *myIndex = [_wifi_detali_tableView indexPathForCell:(UITableViewCell*)[[textField superview]superview]];
NSLog(@"MyIndex.row = %ld",myIndex.row);
[_wifi_detali_tableView selectRowAtIndexPath:myIndex animated:NO scrollPosition:UITableViewScrollPositionNone];
return YES;
}