PageViewController委託函數被調用兩次

我正在使用UIPageViewController來爲我的應用程序進行產品導覽。PageViewController委託函數被調用兩次

我跟着這個鏈接http://www.appcoda.com/uipageviewcontroller-tutorial-intro/

我做的是改變我「根VC」上刷卡，基於索引值，我得到的backgound顏色的簡單的任務，但作爲委託函數被調用兩次，我的指數值是不正確的，因爲這一點，我不能得到它的權利，下面是我的代碼

#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; 
}

請幫我，我沒有得到我要去的地方錯了

個問候蘭吉特

來源

2013-07-12 Ranjit

正是你想要用uiviews或uiviewcontrollers頁面控制 –

@ VivekSehrawat，UIPageViewController的委託功能都只能在VC的工作是什麼。所以我不得不對我們VC – Ranjit

你想改變APPChildViewController或APPViewController的背景顏色嗎？ –

末添加此找了很多之後。

我收到：

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

2函數用來獲取pageViewController後面或電流pageViewController面前。

我認爲這是很難得到當前pageViewController

我的建議：

在UIPageViewControllerDelegate，它有一個功能：

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

此功能給你一個pendingViewControllers陣列，這是當前pageViewController陣列。所以，你可以實現這樣的：

- (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，您可以添加：

self.pageController.delegate = self; 

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

在 'APPViewController.h' 你肯定補充：

@interface APPViewController : UIViewController<UIPageViewControllerDataSource,UIPageViewControllerDelegate>

記住：刪除此代碼（在'viewControllerAtIndex'函數中）

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

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

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

讓我知道你是否有任何問題。

來源

2013-07-12 08:27:07

代表函數沒有被調用 – Ranjit

你補充嗎？：self.pageController.delegate = self; –

對不起，我忘了它 – Ranjit

替換這兩種方法和編譯，

- (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]; 

}

並在- (void)viewDidLoad {

self.view.backgroundColor = [UIColor redColor];

來源

2013-07-12 06:58:32

不行不行 – Ranjit

還不行？ –

是的，仍然無法正常工作 – Ranjit

我面臨同樣的問題，並最終找出原因。當頁面視圖控制器的Transition樣式設置爲「Page Curl」時，將委託方法調用兩次。

當過渡樣式設置爲「頁面捲曲」時，該操作就像在書中翻頁一樣。你翻一頁，頁碼增加2。爲頁面視圖控制器應用相同的概念，2個視圖控制器轉換爲頁面捲曲樣式：一個是您看到的視圖控制器，另一個視圖控制器位於捲曲視圖的另一側。

更改過渡的風格，以「滾動」，你可以擺脫這個問題

這可以從情節串連圖板在屬性檢查器中進行的，如下所示： check image

您還可以更改由同通過將UIPageViewController.transitionStyle屬性設置爲UIPageViewControllerTransitionStyleScroll來進行編碼。

希望它可以幫助

來源

2017-07-26 06:56:16

PageViewController委託函數被調用兩次

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