自定义NavigationBar

[self.navigationController.navigationBarsetHidden:YES];

CGRect screenRect = [[UIScreen mainScreen] bounds];

UINavigationBar *navigationBar = [[UINavigationBar alloc]initWithFrame:CGRectMake(0, 0, screenRect.size.width, 64)];

navigationBar.tintColor = [UIColor greenColor];

navigationBar.alpha=0.3;

//创建UINavigationItem

UINavigationItem *navigationbarTitle = [[UINavigationItem alloc] initWithTitle:@"城市列表"];

[navigationBar pushNavigationItem:navigationbarTitle animated:YES];

navigationBar.backgroundColor =[UIColor clearColor];

//创建UIBarButton

UIBarButtonItem *itemL = [[UIBarButtonItemalloc]initWithBarButtonSystemItem:UIBarButtonSystemItemReplytarget:selfaction:@selector(navigationBackButton:)];

UIBarButtonItem *itemR = [[UIBarButtonItemalloc]initWithBarButtonSystemItem:UIBarButtonSystemItemCameratarget:selfaction:@selector(navigationBackButton:)];

//设置BarButton

navigationbarTitle.leftBarButtonItem = itemL;

navigationbarTitle.rightBarButtonItem = itemR;

[navigationBar setItems:[NSArray arrayWithObject:navigationbarTitle]];

[self.imageView addSubview:navigationBar];