UILabel *showLabel = [[UILabel alloc]init];
showLabel.backgroundColor = [UIColor redColor];
[self.navigationController.view insertSubview:showLabel belowSubview:self.navigationController.navigationBar];
要把一个控件隐藏在navigationBar后面伺机而动怎么办
原文：http://www.cnblogs.com/yintingting/p/4551500.html