UIScrollView

- (void)viewDidLoad{    [super viewDidLoad];        UIScrollView *scrollView = [[UIScrollView alloc]init];    scrollView.frame = CGRectMake(0, 0, 320, 460); //  指UIScrollView的可是范围    scrollView.backgroundColor = [UIColor grayColor];    [self.view addSubview:scrollView];            UIImageView *imageView = [[UIImageView alloc]init];    imageView.image = [UIImage imageNamed:@"big.jpg"];    CGFloat imageW = imageView.image.size.width; //  图片的宽度    CGFloat imageH = imageView.image.size.height; //  图片的高度    imageView.frame = CGRectMake(0,0,imageW,imageH);    [scrollView addSubview:imageView];        //  设置UIScrollView的滚动范围 (内容大小)//    scrollView.contentSize = imageView.image.size;    scrollView.contentSize = CGSizeMake(400, 500);}