//这个方法中设置
+ (void)initialize
{
UINavigationBar *bar = [UINavigationBar appearance];
[bar setBackgroundImage:[UIImage imageNamed:@"bg_navigationBar_normal"] forBarMetrics:UIBarMetricsDefault];
}
- (void)viewDidLoad {
[super viewDidLoad];
// Do any additional setup after loading the view.
}
- (void)didReceiveMemoryWarning {
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
}
在自定义的UINavigationController中设置背景图片
原文：http://www.cnblogs.com/yyj900165/p/4958003.html