UIPageControl + UIScrollView 创建一个页面指示器控件

来源：互联网发布：元数据和数据的区别编辑：程序博客网时间：2024/06/05 16:20

UIPageControl 类提供了一行点来指示当前显示的是多页面视图的哪一页。点击当前颜色鲜艳的页面指示器的左边或右边，会触发 UIControlEventValueChanged 事件，

并启动设置为控件动作的任何方法。你可以通过调用currentPage 查询控件的新值，并通过调整 numberOfPage 属性设置可用的页面数。

代码：使用UIPageControl 指示器

#define BARBUTTON(TITLE, SELECTOR)    [[[UIBarButtonItem alloc] initWithTitle:TITLE style:UIBarButtonItemStylePlain target:self action:SELECTOR] autorelease]
#define RSTRING(X) NSStringFromCGRect(X)

#define BASEHEIGHT   284.0f
#define NPAGES       3

- (void) pageTurn: (UIPageControl *) aPageControl
{
   int whichPage = aPageControl.currentPage;
   [UIView beginAnimations:nil context:NULL];
   [UIView setAnimationDuration:0.3f];
   [UIView setAnimationCurve:UIViewAnimationCurveEaseInOut];
   sv.contentOffset = CGPointMake(320.0f * whichPage, 0.0f);
   [UIView commitAnimations];
}

- (void) scrollViewDidScroll: (UIScrollView *) aScrollView
{
   CGPoint offset = aScrollView.contentOffset;
   pageControl.currentPage = offset.x / 320.0f;
}

- (void) viewDidLoad
{
   self.navigationController.navigationBar.tintColor = COOKBOOK_PURPLE_COLOR;
   self.title = @"Image Scroller";

   // Create the scroll view and set its content size and delegate
   sv = [[[UIScrollView alloc] initWithFrame:CGRectMake(0.0f, 0.0f, 320.0f, BASEHEIGHT)] autorelease];
   sv.contentSize = CGSizeMake(NPAGES * 320.0f, sv.frame.size.height);
   sv.pagingEnabled = YES;
   sv.delegate = self;

   int i = 0;
   // Load in all the pages
   for ( i;i < NPAGES; i++)
   {
       NSString *filename = [NSString stringWithFormat:@"image%d.png", i+1];
       UIImageView *iv = [[UIImageView alloc] initWithImage:[UIImage imageNamed:filename]];
       iv.frame = CGRectMake(i * 320.0f, 0.0f, 320.0f, BASEHEIGHT);
       [sv addSubview:iv];
       [iv release];
   }

   [self.view addSubview:sv];

   pageControl.numberOfPages = 3;
   pageControl.currentPage = 0;
   [pageControl addTarget:self action:@selector(pageTurn:) forControlEvents:UIControlEventValueChanged];
}