使用 UIScrollViewController 进行照片查看

Question

我正在尝试在 iPhone 中制作像 photo.app 这样的相册。我知道我们有来自 Apple 的“PhotoScroller”示例（由于保密协议，我认为我无法将代码复制并粘贴到此处，而且目前使用起来有点大）。然而，我从随机搜索中发现了另一个例子，它似乎是基于 PhotoScroller （非常简化困难）。该示例的链接是； http://ykyuen.wordpress.com/2010/ 05/22/iphone-uiscrollview-with-paging-example/

我将此代码应用到我的项目中来制作相册（至少它可以滚动），但我发现了一个问题。问题是我无法从我想要的页面开始。示例代码仅从第一页开始滚动。代码本身看起来“非常”简单，但不知何故我无法让它从我选择的页面开始。

这是我在互联网上找到的示例代码的主要部分。您当然可以通过上面的链接下载该项目。

- (void)viewDidLoad {

NSLog(@"ScrollViewWithPagingViewContrller::viewDidLoad"); [超级viewDidLoad];

// 视图控制器是延迟创建的 // 同时，加载带有占位符的数组，这些占位符将根据需要进行替换 NSMutableArray *controllers = [[NSMutableArray alloc] init]; for (无符号 i = 0; i < kNumberOfPages; i++) { [控制器addObject:[NSNull null]]; } self.viewControllers = 控制器； [控制者发布]；

// a page is the width of the scroll view
scrollView.pagingEnabled = YES;
scrollView.contentSize = CGSizeMake(scrollView.frame.size.width * kNumberOfPages, scrollView.frame.size.height);
scrollView.showsHorizontalScrollIndicator = NO;
scrollView.showsVerticalScrollIndicator = NO;
scrollView.scrollsToTop = NO;
scrollView.delegate = self;

pageControl.numberOfPages = kNumberOfPages;
pageControl.currentPage = 0;

// pages are created on demand
// load the visible page
// load the page on either side to avoid flashes when the user starts scrolling
[self loadScrollViewWithPage:0];
[self loadScrollViewWithPage:1];}

- (void)loadScrollViewWithPage:(int)page {

NSLog(@"ScrollViewWithPagingViewContrller::loadScrollViewWithPage"); 如果（页数<0）返回； if (page >= kNumberOfPages) return;

// replace the placeholder if necessary


MyViewController *controller = [viewControllers objectAtIndex:page];
if ((NSNull *)controller == [NSNull null]) {
    controller = [[MyViewController alloc] initWithPageNumber:page];
    [viewControllers replaceObjectAtIndex:page withObject:controller];
  //

[控制器释放]； NSLog

// add the controller's view to the scroll view
if (nil == controller.view.superview) {
    CGRect frame = scrollView.frame;
    frame.origin.x = frame.size.width * page;
    frame.origin.y = 0;
    controller.view.frame = frame;
    [scrollView addSubview:controller.view];
}

(@"ScrollViewWithPagingViewContrller::scrollViewDidScroll" )

- (void)scrollViewDidScroll:(UIScrollView *)sender {

;

// We don't want a "feedback loop" between the UIPageControl and the scroll delegate in
// which a scroll event generated from the user hitting the page control triggers updates from
// the delegate method. We use a boolean to disable the delegate logic when the page control is used.
if (pageControlUsed) {
    // do nothing - the scroll was initiated from the page control, not the user dragging
    return;
}

// Switch the indicator when more than 50% of the previous/next page is visible
CGFloat pageWidth = scrollView.frame.size.width;

int page = Floor(scrollView.contentOffset.x - pageWidth / 2) / pageWidth; pageControl.currentPage = 页；

// load the visible page and the page on either side of it (to avoid flashes when the user starts scrolling)
[self loadScrollViewWithPage:page - 1];
[self loadScrollViewWithPage:page];
[self loadScrollViewWithPage:page + 1];

// A possible optimization would be to unload the views+controllers which are no longer visible

}

// At the begin of scroll dragging, reset the boolean used when scrolls originate from the UIPageControl

- (void)scrollViewWillBeginDragging:(UIScrollView *)scrollView { NSLog(@"ScrollViewWithPagingViewContrller::scrollViewWillBeginDragging"); 页面控制已使用=否； }

    // At the end of scroll animation, reset the boolean used when scrolls originate from the UIPageControl

- (void)scrollViewDidEndDecelerating:(UIScrollView *)scrollView { NSLog(@"ScrollViewWithPagingViewContrller::scrollViewDidEndDecelerating"); 页面控制已使用=否； NSLog

- (IBAction)changePage:(id)sender {

(@"ScrollViewWithPagingViewContrller::changePage"); int page = pageControl.currentPage;

// load the visible page and the page on either side of it (to avoid flashes when the user starts scrolling)
[self loadScrollViewWithPage:page - 1];
[self loadScrollViewWithPage:page];
[self loadScrollViewWithPage:page + 1];

// 将滚动视图更新到适当的页面 CGRect框架=scrollView.frame; frame.origin.x =frame.size.width * 页； 框架.origin.y = 0; [scrollViewscrollRectToVisible：帧动画：是]；

// 设置当滚动源自 UIPageControl 时使用的布尔值。请参见上面的scrollViewDidScroll:。 页面控制已使用=是； }

Answer 1

我已经实现了相册视图，在第一个视图中我显示了所有缩略图，单击每个图像时它会提供全屏视图。您还可以浏览图像。
查看此答案。

一切顺利。

Answer 2

答案是

scrollView1.contentOffset = CGPointMake( , );

很简单。花了很多时间。