Question

怎么在一个uiscrollview里添加2个uiviewcontroller

Answer 1

通过ScrollView一个代理方法可以粗糙的实现：
#pragma mark - ScrollView Delegate

- (void)scrollViewDidScrollToTop:(UIScrollView *)scrollView {
if (scrollView.tag == kInnerScrollViewTag) {
[scrollView resignFirstResponder];
}
}

这样的问题就是内部的ScrollView滑到顶部需要松一下手..

或者通过：scrollViewDidScroll:方法调整outerScrollView的ContentOffser也可以做到
#pragma mark - ScrollView Delegate

- (void)scrollViewDidScroll:(UIScrollView *)scrollView {
if (scrollView.tag == kScrollViewTag && scrollView.contentOffset.y < 0) {
CGPoint currentContentOffset = _containerScrollView.contentOffset;

[_containerScrollView setContentOffset:CGPointMake(currentContentOffset.x,
currentContentOffset.y - scrollView.contentOffset.y)
animated:YES];
}
}