为什么我的方法调用两次？

  • Z时代
  • 2024-01-10
  • 分类：问答

我有一个方法在我的页面视图控制器类，这意味着产生一组数字一次，但相反，似乎因为某种原因两次激发？谁能告诉我为什么它的两次发射？为什么我的方法调用两次？

这是控制台火灾

发生了什么，为什么不是它的工作像它应注意什么？

我希望我的页面视图控制器循环，因为用户向前滚动，而我有五个不同的数字，不断循序渐进，但不循环，他们只是无限增加。

刷卡向后方法

-(UIViewController *)pageViewController:(UIPageViewController *)pageViewController 
    viewControllerBeforeViewController:(UIViewController *)viewController 
{ 
    NSUInteger currentIndex = [myViewControllers indexOfObject:viewController]; 
    swipeTotal = swipeTotal - 1; 
    if (swipeTotal > 4) { 
     firstFive = true; 
     // NSLog(@"First Five Passed"); 
    }else{ 
     firstFive = false; 
     // NSLog(@"First Five False"); 
    } 
    // NSLog(@"Swipe Total is %d",swipeTotal); 
    if (currentIndex == 0) { 
     swipeContent1 = swipeTotal; 
     swipeContent2 = swipeTotal + 1; 
     swipeContent3 = swipeTotal + 2; 
     swipeContent4 = swipeTotal - 2; 
     swipeContent5 = swipeTotal - 1; 
    } 
    if (currentIndex == 1) { 
     swipeContent1 = swipeTotal - 1; 
     swipeContent2 = swipeTotal; 
     swipeContent3 = swipeTotal + 1; 
     swipeContent4 = swipeTotal + 2; 
     swipeContent5 = swipeTotal - 2; 
    } 
    if (currentIndex == 2) { 
     swipeContent1 = swipeTotal - 2; 
     swipeContent2 = swipeTotal - 1; 
     swipeContent3 = swipeTotal; 
     swipeContent4 = swipeTotal + 1; 
     swipeContent5 = swipeTotal + 2; 
    } 
    if (currentIndex == 3) { 
     swipeContent1 = swipeTotal + 2; 
     swipeContent2 = swipeTotal - 2; 
     swipeContent3 = swipeTotal - 1; 
     swipeContent4 = swipeTotal; 
     swipeContent5 = swipeTotal + 1; 
    } 
    if (currentIndex == 4) { 
     swipeContent1 = swipeTotal + 1; 
     swipeContent2 = swipeTotal + 2; 
     swipeContent3 = swipeTotal - 2; 
     swipeContent4 = swipeTotal - 1; 
     swipeContent5 = swipeTotal; 
    } 
    if (firstFive == true) { 
    if (currentIndex == 0) { 
     currentIndex = 4; 
    }else{ 
     --currentIndex; 
     currentIndex = currentIndex % (myViewControllers.count); 
    } 
    }else{ 
     if (currentIndex > 0) 
     { 
      return [myViewControllers objectAtIndex:currentIndex-1]; 
      // return the previous viewcontroller 
     } else 
     { 
      return nil; 
      // do nothing 
     } 
    } 
    /* 
     content1 = [users objectAtIndex:swipeContent1]; 
     content2 = [users objectAtIndex:swipeContent2]; 
     content3 = [users objectAtIndex:swipeContent3]; 
     content4 = [users objectAtIndex:swipeContent4]; 
     content5 = [users objectAtIndex:swipeContent5]; */ 
    NSLog(@"Content 1 = %d",swipeContent1); 
    NSLog(@"Content 2 = %d",swipeContent2); 
    NSLog(@"Content 3 = %d",swipeContent3); 
    NSLog(@"Content 4 = %d",swipeContent4); 
    NSLog(@"Content 5 = %d",swipeContent5); 
    return [myViewControllers objectAtIndex:currentIndex]; 
}

刷卡转发方法

-(UIViewController *)pageViewController:(UIPageViewController *)pageViewController 
     viewControllerAfterViewController:(UIViewController *)viewController 
{ 
    NSUInteger currentIndex = [myViewControllers indexOfObject:viewController]; 
    if (swipeTotal > 4) { 
     firstFive = true; 
     //  NSLog(@"First Five Passed"); 
    }else{ 
     firstFive = false; 
     //  NSLog(@"First Five False"); 
    } 
    // NSLog(@"Swipe Total is %d",swipeTotal); 
    ++currentIndex; 
    currentIndex = currentIndex % (myViewControllers.count); 
    swipeTotal = swipeTotal + 1; 
    if (currentIndex == 0) { 
     swipeContent1 = swipeTotal; 
     swipeContent2 = swipeTotal + 1; 
     swipeContent3 = swipeTotal + 2; 
     swipeContent4 = swipeTotal - 2; 
     swipeContent5 = swipeTotal - 1; 
    } else if (currentIndex == 1) { 
     swipeContent1 = swipeTotal - 1; 
     swipeContent2 = swipeTotal; 
     swipeContent3 = swipeTotal + 1; 
     swipeContent4 = swipeTotal + 2; 
     swipeContent5 = swipeTotal - 2; 
    } else if (currentIndex == 2) { 
     swipeContent1 = swipeTotal - 2; 
     swipeContent2 = swipeTotal - 1; 
     swipeContent3 = swipeTotal; 
     swipeContent4 = swipeTotal + 1; 
     swipeContent5 = swipeTotal + 2; 
    } else if (currentIndex == 3) { 
     swipeContent1 = swipeTotal + 2; 
     swipeContent2 = swipeTotal - 2; 
     swipeContent3 = swipeTotal - 1; 
     swipeContent4 = swipeTotal; 
     swipeContent5 = swipeTotal + 1; 
    } else if (currentIndex == 4) { 
     swipeContent1 = swipeTotal + 1; 
     swipeContent2 = swipeTotal + 2; 
     swipeContent3 = swipeTotal - 2; 
     swipeContent4 = swipeTotal - 1; 
     swipeContent5 = swipeTotal; 
    } 
    NSLog(@"Content 1 = %d",swipeContent1); 
    NSLog(@"Content 2 = %d",swipeContent2); 
    NSLog(@"Content 3 = %d",swipeContent3); 
    NSLog(@"Content 4 = %d",swipeContent4); 
    NSLog(@"Content 5 = %d",swipeContent5); 
    return [myViewControllers objectAtIndex:currentIndex]; 
}

回答：

我认为你UIPageViewController需要3控制器（一般），以便能够正确显示其内容：

  1. 主要可见控制器

  2. 上一个

  3. 下一个

此以前和下一个是部分可见的部分时，您的滚动控制器。

因此，您的2种方法不是针对滑动方向分别调用的，而是在您每次滚动控制器时调用。因此，您的滑动内容会被评估两次。

以上是 为什么我的方法调用两次？ 的全部内容， 来源链接： utcz.com/qa/258927.html

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