Question

我有一个UIPageViewController，我已经设置了一个数组作为数据源。我看到第一页正常，并且演示计数点正确显示，但是当我尝试拖动到下一页时没有任何反应。因此，我在viewControllerAfterViewController和Before方法中设置了一些断点，并且它们永远不会被调用。 presentationCountForPageViewController的其他dataSource方法被调用。

知道我错过了什么吗？我已经在网上找到了我在网上找到的但却无法找到的例子。

- (void)viewDidLoad
{
   [super viewDidLoad];

   UIPageViewController *pageController = self.pageController;
   pageController.dataSource = self;

   UIChildViewController *initialViewController = [self viewControllerAtIndex:0];
   NSArray *viewControllers = @[initialViewController];
   [pageController setViewControllers:viewControllers direction:UIPageViewControllerNavigationDirectionForward animated:YES completion:nil];

   [self addChildViewController:pageController];
   [self.view addSubview:pageController.view];
   [pageController didMoveToParentViewController:self];
  }

- (UIPageViewController *)pageController
{
   return !_pageController ? _pageController =
      ({
          UIPageViewController *value = [[UIPageViewController alloc] initWithTransitionStyle:UIPageViewControllerTransitionStyleScroll
                                                                  navigationOrientation:UIPageViewControllerNavigationOrientationHorizontal
                                                                                options:nil];
          value.view.frame = self.view.bounds;
          value;
   }) : _pageController;
}

- (UIViewController *)pageViewController:(UIPageViewController *)pa geViewController viewControllerBeforeViewController:(UIChildViewController *)viewController
{
   NSUInteger index = viewController.index;
   return (index == 0 ) ? nil : [self viewControllerAtIndex:--index];
}

- (UIViewController *)pageViewController:(UIPageViewController *)pageViewController viewControllerAfterViewController:(UIChildViewController *)viewController
{
   NSUInteger index = viewController.index;
   index++;
   return (index == self.myDataSourceArray.count) ? nil : [self viewControllerAtIndex:index];
}

- (UIChildViewController *)viewControllerAtIndex:(NSUInteger)index
{
   UIChildViewController *childViewController = [UIChildViewController new];
   childViewController.view.frame = self.pageController.view.bounds;
   childViewController.index = index;

   ...

   return childViewController;
}

- (NSInteger)presentationCountForPageViewController:   (UIPageViewController *)pageViewController
{
   // The number of items reflected in the page indicator.
   return self.myDataSourceArray.count;
}

- (NSInteger)presentationIndexForPageViewController:(UI PageViewController *)pageViewController
{
   // The selected item reflected in the page indicator.
   return 0;
}

Answer 1

问题在于，在包含封装UIPageViewController的UIViewController子类时，我忘记在父视图控制器的let FunctionFactory<'T> = let s = 0.0 |> Seq.unfold (fun i -> Some(i, if 0.0 = i then 1.0 else 0.0)) (fun (ignoredParam:'T) -> Seq.next s )中包含viewDidLoad和addChildViewController

didMoveToParentViewController

解决了问题。

UIPageViewController viewControllerAfterViewController从未调用过

1 个答案: