Ios 调用两次PageViewController委托函数

我正在与UIPageViewController合作，为我的应用程序进行产品介绍

我跟踪了这个链接

我正在做的是一项简单的任务，根据我得到的索引值，在滑动时更改我的“根VC”的背景颜色，但由于委托函数被调用了两次，我的索引值不正确，因此，我无法正确获得它，下面是我的代码

#import "APPViewController.h"
#import "APPChildViewController.h"

@interface APPViewController ()

@end

@implementation APPViewController

- (void)viewDidLoad {

    [super viewDidLoad];

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

    self.pageController.dataSource = self;
    [[self.pageController view] setFrame:CGRectMake(0, 0, 320, 500)];

    APPChildViewController *initialViewController = [self viewControllerAtIndex:0];

    NSArray *viewControllers = [NSArray arrayWithObject:initialViewController];

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

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

}

- (void)didReceiveMemoryWarning {

    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.

}

- (APPChildViewController *)viewControllerAtIndex:(NSUInteger)index {

    APPChildViewController *childViewController = [[APPChildViewController alloc] initWithNibName:@"APPChildViewController" bundle:nil];
    childViewController.index = index;
    childViewController.view.backgroundColor = [UIColor clearColor];

    if(index == 0)
    {
          self.view.backgroundColor = [UIColor redColor];
     }

    if(index == 1)
    {
          self.view.backgroundColor = [UIColor blueColor];
     }

    if(index == 2)
    {
          self.view.backgroundColor = [UIColor greenColor];
     }


    return childViewController;

}

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

    NSUInteger index = [(APPChildViewController *)viewController index];

    if (index == 0) {
        return nil;
    }

    // Decrease the index by 1 to return
    index--;

   return [self viewControllerAtIndex:index];

}

- (UIViewController *)pageViewController:(UIPageViewController *)pageViewController viewControllerAfterViewController:(UIViewController *)viewController {

    NSUInteger index = [(APPChildViewController *)viewController index];

    index++;

    if (index == 3) {
        return nil;
    }

   return [self viewControllerAtIndex:index];

}

- (NSInteger)presentationCountForPageViewController:(UIPageViewController *)pageViewController {
    // The number of items reflected in the page indicator.
    return 3;
}

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

请帮帮我，我不会错的

问候

---

Ranjit

替换这两个方法并编译

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

    NSUInteger index = [(APPChildViewController *)viewController index];
    if (index == 0)
    {
        self. view.backgroundColor = [UIColor redColor];
        return nil;
    }

    if(index == 1)
    {
        self.view.backgroundColor = [UIColor blueColor];
    }

    if(index == 2)
    {
        self.view.backgroundColor = [UIColor greenColor];
    }
    if(index == 3)
    {
        self.view.backgroundColor = [UIColor brownColor];
    }
    /*if(index == 4)
    {
        self.view.backgroundColor = [UIColor whiteColor];
    }*/

    // Decrease the index by 1 to return
    index--;

    return [self viewControllerAtIndex:index];

}

- (UIViewController *)pageViewController:(UIPageViewController *)pageViewController viewControllerAfterViewController:(UIViewController *)viewController {

    NSUInteger index = [(APPChildViewController *)viewController index];
    /*if(index == 0)
    {
        self.view.backgroundColor = [UIColor redColor];
    }*/
    if(index == 1)
    {
        self.view.backgroundColor = [UIColor blueColor];
    }

    if(index == 2)
    {
        self.view.backgroundColor = [UIColor greenColor];
    }
    if(index == 3)
    {
        self.view.backgroundColor = [UIColor brownColor];
    }
    if(index == 4)
    {
        self.view.backgroundColor = [UIColor whiteColor];
        return nil;
    }

    /*if (index == 5) {
        return nil;
    }*/
    index++;

    return [self viewControllerAtIndex:index];

}

并将其添加到

-（void）viewDidLoad{

---

self.view.backgroundColor=[UIColor redColor]；

在寻找了很多之后

我收到：

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

2个函数用于使pageViewController位于当前pageViewController的后面或前面

我认为很难获得当前的pageViewController

我的建议是：

在UIPageViewControllerDelegate中，它具有以下功能：

 - (void)pageViewController:(UIPageViewController *)pageViewController willTransitionToViewControllers:(NSArray *)pendingViewControllers;

此函数用于为您提供PendingViewController数组和当前的pageViewController数组。 因此，您可以这样实现：

- (void)pageViewController:(UIPageViewController *)pageViewController willTransitionToViewControllers:(NSArray *)pendingViewControllers
{


if([pendingViewControllers count]>0)
  {
     NSUInteger index =[(APPChildViewController*)[pendingViewControllers objectAtIndex:0] index];

    if(index == 0)
    {
        self.view.backgroundColor = [UIColor redColor];
    }

    if(index == 1)
    {
        self.view.backgroundColor = [UIColor blueColor];
    }

    if(index == 2)
    {
        self.view.backgroundColor = [UIColor greenColor];
    }


  }
}

在viewDidLoad中，添加：

    self.pageController.delegate = self;

    self.view.backgroundColor = [UIColor redColor]; //set first background.

在“APPViewController.h”中，确实要添加：

@interface APPViewController : UIViewController<UIPageViewControllerDataSource,UIPageViewControllerDelegate>

---

如果您有任何问题，请告诉我。

我遇到了同样的问题，并最终找到了原因。 当页面视图控制器的转换样式设置为“page Curl”时，将调用委托方法两次

当转换样式设置为“页面卷曲”时，操作就像翻书一样。翻开一页，页码就会增加2。 将相同的概念应用于页面视图控制器，将为页面卷曲样式转换两个视图控制器：一个是您看到的视图控制器，另一个视图控制器位于卷曲视图的另一侧

将转换样式更改为“滚动”，就可以解决此问题

这可以通过属性检查器中的情节提要完成，如下所示：

通过将UIPageViewController.transitionStyle属性设置为UIPageViewControllerTransitionStyleScroll，还可以通过代码更改相同的设置

---

希望它能帮助你

你到底想要一个带有UIView或uiviewcontrollers@VivekSehrawat，UIPageViewController的委托函数只能与VC一起使用。因此，我必须告诉我们，您想更改APPChildViewController或APPViewController的背景色吗？@NguyenThiThuyTrang，更改APPViewController@Ranjit ：我有一个答案。并测试了它…你可以在上面尝试。委托函数没有被调用。你添加了吗？：self.pageController.delegate=self；这个函数在Simulator 6.0中可用

pendingViewController

是一个NSMutable视图控制器数组？你能添加它的代码吗？@Andronienn:是的，pendingViewController是NSMu视图控制器的tableArray。以及“您能添加其代码吗？”您的意思是什么？请详细解释。仅当您尝试从页面控制器更改页面而不是滑动手势时，这将不起作用。

if(index == 1)
{
    self.view.backgroundColor = [UIColor redColor];
}

if(index == 2)
{
    self.view.backgroundColor = [UIColor blueColor];
}

if(index == 3)
{
    self.view.backgroundColor = [UIColor greenColor];
}