当在- (void)scrollViewDidScroll:(UIScrollView *)scrollView打印NSLog(@"%.f", scrollView.contentOffset.y);时,发现数值为-20,说明self.viewY值没有以顶点开始,而是在状态栏之下。
- (void)scrollViewDidScroll:(UIScrollView *)scrollView
NSLog(@"%.f", scrollView.contentOffset.y);
self.view
- (void)viewDidLoad
self.edgesForExtendedLayout = UIRectEdgeNone;