Question

我正在创建一个iOS应用程序，它有一个UIPageViewController，如果还没有添加任何其他内容，则会加载默认页面，并且用户可以在应用程序中添加页面。但是，初始视图永远不会随着其他视图的添加而改变。

我尝试过这些问题的答案：
Is it possible to Turn page programmatically in UIPageViewController?
Changing UIPageViewController's page programmatically doesn't update the UIPageControl
Removing a view controller from UIPageViewController
Refresh a UIPageViewController

它们都不适合我。视图仍然保留在初始页面，直到我重新加载应用程序，之后，页面显示正常，我可以添加任意多个。

这是我制作PageView和页面的代码

- (void)viewDidLoad
{
    [super viewDidLoad];

    self.pageController = [[UIPageViewController alloc] initWithTransitionStyle:UIPageViewControllerTransitionStyleScroll navigationOrientation:UIPageViewControllerNavigationOrientationHorizontal options:nil];

    self.pageController.dataSource = self;
    [[self.pageController view] setFrame:[[self pageControllerView] bounds]];

    UIViewController *initialViewController = [self viewControllerAtIndex:0];

    __block Page1ViewController *blocksafeSelf = self;

    // This doesn't work either... :(
    void (^completionBlock)(BOOL) = ^(BOOL finished)
    {
        // It seems that whenever the setViewControllers:
        // method is called with "animated" set to YES, UIPageViewController precaches
        // the view controllers retrieved from it's data source meaning that
        // the dismissed controller might not be removed. In such a case we
        // have to force it to clear the cache by initiating a non-animated
        // transition.
        usleep(1);
        dispatch_async(dispatch_get_main_queue(), ^(){
            [blocksafeSelf.pageController setViewControllers:@[initialViewController]
                                      direction:UIPageViewControllerNavigationDirectionForward
                                       animated:NO
                                     completion:nil];
        });
    };

    [self.pageController setViewControllers:@[initialViewController]
                              direction:UIPageViewControllerNavigationDirectionForward
                               animated:YES
                             completion:completionBlock];

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

- (void)reloadViews
{
    [[self childViewControllers] makeObjectsPerformSelector:@selector(removeFromParentViewController)];
    [[self.view subviews] makeObjectsPerformSelector:@selector(removeFromSuperview)];

    [self.pageController willMoveToParentViewController:nil];
    [self.pageController removeFromParentViewController];
    [self.pageController.view removeFromSuperview];
    self.pageController = nil;
    self.pageController = [[UIPageViewController alloc] init];

    [self.view setNeedsDisplay];
}

- (UIViewController *)pageViewController:(UIPageViewController *)pageViewController viewControllerAfterViewController:(UIViewController *)viewController
{
    NSUInteger index = ((SomethingViewController *)viewController).index;
    index++;

    if (index >= [Settings somethings].count)
    {
        return nil;
    }

    return [self viewControllerAtIndex:index];
}

- (UIViewController *)viewControllerAtIndex:(NSUInteger)index
{
    UIStoryboard *sb = [UIStoryboard storyboardWithName:@"Storyboard_iPhone"
                                              bundle:nil];
    if ([Settings somethings].count == 0 && index == 0)
    {
        NoSomethingViewController *vc = [sb instantiateViewControllerWithIdentifier:@"NoSomethingViewController"];
        vc.index = index;
        return vc;
    }

    SomethingViewController *childViewController = [sb instantiateViewControllerWithIdentifier:@"SomethingViewController"];
    childViewController.something = [[Settings somethings] somethingAtIndex:index];
    childViewController.index = index;

    return childViewController;
}

当应该创建一个新页面时，通过在something数组中添加somethings，我从View控制器调用re something来添加viewControllerAtIndex。然后代码点击{{1}}的第二部分，但是我在手机上看到的页面上没有显示，因为我仍然看到NoSomethingViewController和它的视图。

如果您需要更多代码，我会提供。

Answer 1

在pageViewController viewWillAppear方法

中添加以下代码

dataSource = self

并在viewWillDisappear中添加

dataSource = nil

这将强制pageViewController重新加载其dataSource

Answer 2

要显示当前点，请不要忘记您必须更新页面指示符

- (NSInteger)presentationIndexForPageViewController:(UIPageViewController *)pageViewController

如何更新UIPageControl指标https://stackoverflow.com/a/22576250/3897011

的示例

Answer 3

经过很长一段时间，在浪费了与Apple的支持票之后，我决定采用另一种方法。

在我的故事板中，我创建了2个不同的导航控制器，每个情况一个（如果有somethings，如果没有），我有viewDidAppear的初始视图控制器，实例化其中一个并呈现它。这样，我确保整个导航控制器正确重新加载。

UINavigationController *nc;

if ([Settings somethings].count)
{
    nc = [self.storyboard instantiateViewControllerWithIdentifier:@"NavigationController"];
}
else
{
    nc = [self.storyboard instantiateViewControllerWithIdentifier:@"NoSomethingNavigationController"];
}

self.nc = nc;

[self presentViewController:nc animated:NO completion:nil];

Answer 4

要重新加载UIPageViewController，您可以使用以下代码：

[self.pageController setViewControllers:@[yourCurrentController]
                                      direction:UIPageViewControllerNavigationDirectionForward
                                       animated:NO
                                     completion:nil];

还请实施

- (UIViewController *)pageViewController:(UIPageViewController *)pageViewController viewControllerBeforeViewController:(UIViewController *)viewController

方法

在UIPageViewController中重新加载视图

4 个答案: