我有一个 UIPageControl
可以翻阅不同的页面。当用户从第 1 页滚动到第 2 页时,我想让 UIImageView 开始淡出。我正在努力找出根据位置添加图层的正确方法。任何帮助将不胜感激...
[UIView beginAnimations:@"fade out" context:nil];
[UIView setAnimationDuration:1.0]; // some how based on position??
imageView.alpha = 1.0; // here to?
[UIView commitAnimations];
编辑:
设置委托(delegate):
self.pageController = [[UIPageViewController alloc] initWithTransitionStyle:UIPageViewControllerTransitionStyleScroll navigationOrientation:UIPageViewControllerNavigationOrientationHorizontal options:nil];
self.pageController.dataSource = self;
最佳答案
您需要委托(delegate)重写以下方法:
- (void)scrollViewDidScroll:(UIScrollView *)scrollView;
然后您应该检查 scrollView.contentOffset.x
值以确定 ScrollView 水平滚动了多少,并使用它来确定您的 imageView 的 alpha,如下所示:
CGFloat newAlpha = scrollView.contentOffset.x / scrollView.frame.size.width; // This will need to be adapted depending on the content size of your scroll view -- do not just copy and paste this expecting it to work :)
imageView.alpha = newAlpha;
关于ios - 基于 ScrollView Position 的 UIImageView Fading,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/18245647/