ios - 我怎么知道 UIPageViewController 是向前翻转还是向后翻转？

Question

我有一个 UIPageViewController，但我不知道如何知道用户将页面转到哪个方向，以便我可以适本地设置页数。

谢谢沙尼

Answer 1

正如汉志所说

After a gesture-driven transition completes this delegate method is called:

pageViewController:didFinishAnimating:previousViewControllers:transitionCompleted:

需要说明的是，completed如果页面完全打开则为YES，如果页面没有打开则为NO实际上没有转。 NO 情况发生，例如，当用户只是拉起页面的一角然后在没有翻转页面的情况下将其放回原处。

这是您要实现的概念:

- (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;
    }

    // This is where you would know the page number changed and handle it appropriately
    // [self sendPageChangeNotification:YES];
}