代码：

#import "RootViewController.h"@implementation RootViewController@synthesize scrollView;- (void)viewDidLoad{    [super viewDidLoad];    // Do any additional setup after loading the view.        int pageCount = 3;    scrollView = [[UIScrollView alloc]initWithFrame:[[UIScreen mainScreen] applicationFrame]];    [self.view addSubview:scrollView];        scrollView.backgroundColor = [UIColor redColor];    scrollView.scrollEnabled = NO;    scrollView.contentSize = CGSizeMake(scrollView.frame.size.width * pageCount, scrollView.frame.size.height);    scrollView.pagingEnabled = YES;    scrollView.showsHorizontalScrollIndicator = YES;    scrollView.delegate = self;        CGRect rect = [[UIScreen mainScreen]bounds];    NSArray *colors = [NSArray arrayWithObjects:[UIColor yellowColor], [UIColor blueColor], [UIColor purpleColor], nil];        for (int i = 0; i < pageCount; i++) {                CGRect aRect = CGRectMake(rect.origin.x + (i * rect.size.width), rect.origin.y,                                  rect.size.width, rect.size.height);        UIView *view1 = [[UIView alloc]initWithFrame:aRect];        view1.backgroundColor = colors[i];        [scrollView addSubview:view1];    }        [self moveToPage:3];}- (void) moveToPage:(int)index{    index--;    CGRect rect = [[UIScreen mainScreen]bounds];    CGPoint point = CGPointMake(rect.size.width * index, 0);    [scrollView setContentOffset:point];}- (void)scrollViewDidEndDecelerating:(UIScrollView *)scrollView{    // 拖拽完毕以后调用    int index = [self getPageIndex:scrollView];    NSLog(@"index = %d",index);}-(int) getPageIndex:(UIScrollView *)scrollView{    return fabs(scrollView.contentOffset.x) /  scrollView.frame.size.width;}@end