iphone - 向后或向前滑动时检查 UIPageViewController

Question

我想使用 UIPageViewController 跟踪索引。每当我滑动时，我都需要 index++ 或 index--。每当您向后或进一步滑动时，都会调用此委托(delegate)方法:

- (void)pageViewController:(UIPageViewController *)pvc didFinishAnimating:(BOOL)finished previousViewControllers:(NSArray *)previousViewControllers transitionCompleted:(BOOL)completed
{
    // If the page did not turn
    if (!completed)
    {
        // You do nothing because whatever page you thought
        // the book was on before the gesture started is still the correct page
        return;
    }

    // I want to check here whenever the page was swiped back or further
}

如果用户向后或进一步滑动，我如何检查此方法？我知道有两种数据源方法“viewControllerAfterViewController”和“viewControllerBeforeViewController”但是我无法检查页面转换是否已经完成(我可以在上面的方法中做到这一点)不知道我怎么知道用户是否向后滑动或进一步滑动上面的方法？

Answer 1

使用协议(protocol):

MyClass : UIViewController <UIPageViewControllerDataSource,UIPageViewControllerDelegate

声明一个属性:

@property(nonatomic) NSInteger currentIndex;
@property(nonatomic) NSInteger nextIndex;

在方法中:

-(void)pageViewController:(UIPageViewController *)pageViewController willTransitionToViewControllers:(NSArray *)pendingViewControllers{
    NewsTableViewController *controller  = [pendingViewControllers firstObject];
    self.nextIndex = [self.arrViews indexOfObject:controller];
}

-(void)pageViewController:(UIPageViewController *)pageViewController didFinishAnimating:(BOOL)finished previousViewControllers:(NSArray *)previousViewControllers transitionCompleted:(BOOL)completed{
    if (completed) {
        self.currentIndex = self.nextIndex;
    }
    self.nextIndex = 0;
}

您将看到当前页面。感谢 Corey Floyd 在 enter link description here