//设置背景图片

[self.navigationController.navigationBar setBackgroundImage:imag forBarMetrics:UIBarMetricsDefault];

//button 定义你要的背景 文字 或 事件

UIBarButtonItem *leftBarButton = [[UIBarButtonItem alloc] initWithCustomView:button];

self.navigationItem.leftBarButtonItem = leftBarButton;

[leftBarButton release];

具体实现：

[self.navigationItem setTitle:@"通知详情"];

//self.navigationController.navigationBarHidden = NO;

[self.navigationController.navigationBar setBackgroundImage:[UIImage imageNamed:@"root_top.png"] forBarMetrics:UIBarMetricsDefault];

self.navigationItem.hidesBackButton = YES;

UIButton *rightButton = [[UIButton alloc]initWithFrame:CGRectMake(SCREEN_WIDTH - 70, 10, 70, rootTopHeight - 20)];

[rightButton addTarget:self action:@selector(NoticeBackAction) forControlEvents:UIControlEventTouchUpInside];

[rightButton setBackgroundImage:[UIImage imageNamed:@"root_back.png"] forState:UIControlStateNormal];

[rightButton setTitle:@"退出" forState:UIControlStateNormal];

UIBarButtonItem *rightBarButton = [[UIBarButtonItem alloc]initWithCustomView:rightButton];

self.navigationItem.rightBarButtonItem = rightBarButton;