ios - 禁用 UIPageViewController 反弹

Question

为此搜索了很多，但还没有找到合适的解决方案。

是否可以禁用 UIPageViewController 的反弹效果并仍然使用 UIPageViewControllerTransitionStyleScroll？

Answer 1

禁用 UIPageViewController 的反弹

1. 添加<UIScrollViewDelegate>委托(delegate)给你的 UIPageViewController 的标题

2. 在 viewDidLoad 中将 UIPageViewController 的底层 UIScrollView 的委托(delegate)设置为其父级:

   for (UIView *view in self.view.subviews) {
       if ([view isKindOfClass:[UIScrollView class]]) {
           ((UIScrollView *)view).delegate = self;
           break;
       }
   }
   

3. scrollViewDidScroll的实现是将contentOffset重置为原点(NOT (0,0), but (bound.size.width, 0) ) 当用户超出范围时，像这样:

   - (void)scrollViewDidScroll:(UIScrollView *)scrollView {
       if (_currentPage == 0 && scrollView.contentOffset.x < scrollView.bounds.size.width) {
           scrollView.contentOffset = CGPointMake(scrollView.bounds.size.width, 0);
       } else if (_currentPage == totalViewControllersInPageController-1 && scrollView.contentOffset.x > scrollView.bounds.size.width) {
           scrollView.contentOffset = CGPointMake(scrollView.bounds.size.width, 0);
       }
   }
   

4. 最后，scrollViewWillEndDragging的实现是为了处理用户在第一页从左向右快速滑动，第一页不会向左弹跳的bug场景(由于上述功能)，但会因(可能)滑动速度而在右侧反弹。最后，当反弹回来时，UIPageViewController 将触发翻页到第二页(这当然不是预期的)。

   - (void)scrollViewWillEndDragging:(UIScrollView *)scrollView withVelocity:(CGPoint)velocity targetContentOffset:(inout CGPoint *)targetContentOffset {
       if (_currentPage == 0 && scrollView.contentOffset.x <= scrollView.bounds.size.width) {
           *targetContentOffset = CGPointMake(scrollView.bounds.size.width, 0);
       } else if (_currentPage == totalViewControllersInPageController-1 && scrollView.contentOffset.x >= scrollView.bounds.size.width) {
           *targetContentOffset = CGPointMake(scrollView.bounds.size.width, 0);
       }
   }
   

swift 4.0

要放入 viewDidLoad 的代码:

for subview in self.view.subviews {
    if let scrollView = subview as? UIScrollView {
        scrollView.delegate = self
        break;
    }
}

scrollViewDidScroll的实现:

func scrollViewDidScroll(_ scrollView: UIScrollView) {
    if (currentPage == 0 && scrollView.contentOffset.x < scrollView.bounds.size.width) {
        scrollView.contentOffset = CGPoint(x: scrollView.bounds.size.width, y: 0);
    } else if (currentPage == totalViewControllersInPageController - 1 && scrollView.contentOffset.x > scrollView.bounds.size.width) {
        scrollView.contentOffset = CGPoint(x: scrollView.bounds.size.width, y: 0);
    }
}

scrollViewWillEndDragging的实现:

func scrollViewWillEndDragging(_ scrollView: UIScrollView, withVelocity velocity: CGPoint, targetContentOffset: UnsafeMutablePointer<CGPoint>) {
    if (currentPage == 0 && scrollView.contentOffset.x <= scrollView.bounds.size.width) {
        targetContentOffset.pointee = CGPoint(x: scrollView.bounds.size.width, y: 0);
    } else if (currentPage == totalViewControllersInPageController - 1 && scrollView.contentOffset.x >= scrollView.bounds.size.width) {
        targetContentOffset.pointee = CGPoint(x: scrollView.bounds.size.width, y: 0);
    }
}