如何在导航栏中添加页面指示器？

Question

像twitter一样:

我在UITabBarController中有一个PageViewController,而UITabBarController又在UINavigationController中.

谁能告诉我如何在导航栏中显示页面指示器？

Answer 1

编辑:我刚刚发现navigationController.viewControllers只包含堆栈.我会在一分钟内发布一个编辑

编辑2:嗯,似乎你必须事先知道视图控制器的数量.

也许不是最好的解决方案,但它对我有用.刚试过:)

@interface ViewController () <UINavigationControllerDelegate>
@property (nonatomic, strong) UIPageControl *pageControl;
@end

@implementation ViewController

- (void)viewDidLoad
{
    [super viewDidLoad];

    UINavigationController *navController = self.navigationController;
    navController.delegate = self;

    navController.navigationBar.barTintColor = [UIColor colorWithRed:.2
                                                               green:.4
                                                                blue:.9
                                                               alpha:1];

    CGSize navBarSize = navController.navigationBar.bounds.size;
    CGPoint origin = CGPointMake( navBarSize.width/2, navBarSize.height/2 );

    self.pageControl = [[UIPageControl alloc] initWithFrame:CGRectMake(origin.x, origin.y,
                                                                       0, 0)];

    //Or whatever number of viewcontrollers you have
    [self.pageControl setNumberOfPages:2];

    [navController.navigationBar addSubview:self.pageControl];

    navController.delegate = self;
}

- (void)navigationController:(UINavigationController *)navigationController willShowViewController:(UIViewController *)viewController animated:(BOOL)animated
{
    int index = [navigationController.viewControllers indexOfObject:viewController];
    self.pageControl.currentPage = index;
}

@end

这是一些截图.