iOS 状态栏和导航条配置
一：隐藏：
[self.navigationController setNavigationBarHidden:YES animated:YES];
[[UIApplication sharedApplication] setStatusBarStyle:UIStatusBarStyleDefault animated:YES];
二：状态值
参考：http://beyondvincent.com/blog/2013/11/03/120-customize-navigation-status-bar-ios-7/