ios - 设置 contentInset 或 automaticAdjustsScrollViewInsets 后我需要做什么才能实际应用它？

Question

我有一个UIViewController包含一个UIScrollView. 最初automaticallyAdjustsScrollViewInsets没有设置（所以它应该默认为YES）。

在某些用户交互上我设置automaticallyAdjustsScrollViewInsets为，所以我可以在滚动视图上NO设置我自己的。contentInset

这样做之后什么也没有发生。之后我要打什么电话？

调用setNeedsDisplay滚动视图没有帮助。

Answer 1

If you want your initial display of your scrollview to include an initial content offset, then set the contentInset value in viewDidLoad. If you wish to dynamically change the contentInset and have the contentOffset change as well, then you need to adjust the contentOffset at the same time as the contentInset. For example:

// Adjust content inset and initial offset to account for the header
UIEdgeInsets contentInset = self.collectionView.contentInset;
contentInset.top += self.stickyHeaderView.bounds.size.height;
self.collectionView.contentInset = contentInset;
if (-1 * self.collectionView.contentOffset.y < contentInset.top) {
    CGPoint contentOffset = self.collectionView.contentOffset;
    contentOffset.y = -1*contentInset.top;
    [self.collectionView setContentOffset:contentOffset animated:YES];
}