本来我的statusbar是lightcontent的，结果用UIImagePickerController会导致我的statusbar的样式变成黑色，怎么办？

  - (void)navigationController:(UINavigationController *)navigationController willShowViewController:(UIViewController *)viewController animated:(BOOL)animated
{
[[UIApplication sharedApplication] setStatusBarStyle:UIStatusBarStyleLightContent];
}

怎么把我的navigationbar弄成透明的而不是带模糊的效果？

[self.navigationBar setBackgroundImage:[UIImage new]
                     forBarMetrics:UIBarMetricsDefault];
self.navigationBar.shadowImage = [UIImage new];
self.navigationBar.translucent = YES;

文／叶孤城___（简书作者）
原文链接：http://www.jianshu.com/p/08f194e9904c

UIImageView默认的userInteractionEnabled = NO.所以要想图片中的按钮被点击需要设置

imageView.userInteractionEnabled = YES;

定制导航栏的返回按钮

// 隐藏默认的"返回"按钮
[self.navigationItem setHidesBackButton:YES];

// 自定义导航栏的"返回"按钮

UIButton *btn = [UIButton buttonWithType:UIButtonTypeCustom];

btn.frame = CGRectMake(15, 5, 35, 35);

[btn setBackgroundImage:[UIImage imageNamed:@"photo_left_nav"] forState:UIControlStateNormal];

[btn addTarget:self action:@selector(goBackAction) forControlEvents:UIControlEventTouchUpInside];
UIBarButtonItem * back=[[UIBarButtonItem alloc]initWithCustomView:btn];
// 设置导航栏的leftButton

self.navigationItem.leftBarButtonItem=back;