NavigationController

隐藏导航栏

self.navigationController.navigationBarHidden = NO;

把导航栏返回功能按钮  名称和功能

self.navigationItem.leftBarButtonItem = [[UIBarButtonItem alloc]initWithTitle:@"<返回" style:UIBarButtonItemStylePlain target:self action:@selector(backAction:)];

设置导航栏的颜色   导航那一条的颜色

self.navigationController.navigationBar.tintColor = [UIColor colorWithRed:3/255.f green:205/255.f blue:134/255.f alpha:1];

设置导航栏的背景  置为空

[self.navigationController.navigationBar setBackgroundImage:[UIImage alloc] forBarMetrics:UIBarMetricsDefault];

设置导航栏的下划线颜色 

self.navigationController.navigationBar.shadowImage = [[UIImage alloc]init];

导航栏变透明

self.navigationController.navigationBar.translucent = YES;