UIScrollView的简单使用，可用来实现简单的相册

#import <UIKit/UIKit.h>
@interface MainViewController : UIViewController<UIScrollViewAccessibilityDelegate>
@end

#import "MainViewController.h"
@interface MainViewController ()
@end
@implementation MainViewController
- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
{
    self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
    if (self) {
        // Custom initialization
    }
    return self;
}
- (void)viewDidLoad
{
    [super viewDidLoad];
    // Do any additional setup after loading the view.
    
    //UIScrollView的使用
    UIScrollView *scrollView = [[UIScrollView alloc] initWithFrame:CGRectMake(20, 20, 280, 350)];
    scrollView.backgroundColor = [UIColor brownColor];
//    scrollView.alpha = 0.3;
    [self.view addSubview:scrollView];
    [scrollView release];
    //scorllView的滚动范围
    scrollView.contentSize = CGSizeMake(840, 0);
    //scorllView能否滚动
    scrollView.scrollEnabled = YES;
    //是否可以迅速回到顶部
    scrollView.scrollsToTop = YES;  //点击状态栏迅速回到顶部
    //scorllView按页翻动
    scrollView.pagingEnabled = YES;
    //边缘的弹动效果
    scrollView.bounces = YES;
    //scrollView的偏移量
    scrollView.contentOffset = CGPointMake(0, 0);  //默认为CGPonintMake(0,0)
    //scrollView的代理
    scrollView.delegate = self;
    
    //设置scrollView的缩放
    //1.设置缩放范围
    scrollView.maximumZoomScale = 2.0;
    scrollView.minimumZoomScale = 0.5;
    
    //创建存放p_w_picpathView的可缩放的scrollView1
    UIScrollView *scrollView1 = [[UIScrollView alloc] initWithFrame:CGRectMake(0, 0, 280, 350)];
    scrollView1.delegate = self;
    scrollView1.maximumZoomScale = 2.0;
    scrollView1.minimumZoomScale = 0.5;
    [scrollView addSubview:scrollView1];
    [scrollView1 release];
    
    //创建存放p_w_picpathView1的可缩放的scrollView2
    UIScrollView *scrollView2 = [[UIScrollView alloc] initWithFrame:CGRectMake(280, 0, 280, 350)];
    scrollView2.delegate = self;
//    scrollView2.backgroundColor = [UIColor redColor];
    scrollView2.maximumZoomScale = 2.0;
    scrollView2.minimumZoomScale = 0.5;
    [scrollView addSubview:scrollView2];
    [scrollView2 release];
    
    //创建存放p_w_picpathView2的可缩放的scrollView3
    UIScrollView *scrollView3 = [[UIScrollView alloc] initWithFrame:CGRectMake(560, 0, 280, 350)];
    scrollView3.delegate = self;
    //    scrollView2.backgroundColor = [UIColor redColor];
    scrollView3.maximumZoomScale = 2.0;
    scrollView3.minimumZoomScale = 0.5;
    [scrollView addSubview:scrollView3];
    [scrollView3 release];
    
    
    //创建3个p_w_picpathView  分别将它们放在scrollView1、scrollView2、scrollView3上面
    UIImageView *p_w_picpathView = [[UIImageView alloc] initWithFrame:CGRectMake(0, 0, 280, 350)];
    UIImageView *p_w_picpathView1 = [[UIImageView alloc] initWithFrame:CGRectMake(0, 0, 280, 350)];
    UIImageView *p_w_picpathView2 = [[UIImageView alloc] initWithFrame:CGRectMake(0, 0, 280, 350)];
    p_w_picpathView.p_w_picpath = [UIImage p_w_picpathNamed:@"1.jpg"];
    p_w_picpathView1.p_w_picpath = [UIImage p_w_picpathNamed:@"2.jpg"];
    p_w_picpathView2.p_w_picpath = [UIImage p_w_picpathNamed:@"3.jpg"];
    [scrollView1 addSubview:p_w_picpathView];
    [scrollView2 addSubview:p_w_picpathView1];
    [scrollView3 addSubview:p_w_picpathView2];
    [p_w_picpathView2 release];
    [p_w_picpathView1 release];
    [p_w_picpathView release];
    
}
//缩放的设置：2 指定一个scrollView的子视图，跟着scrollView缩放
- (UIView *)viewForZoomingInScrollView:(UIScrollView *)scrollView
{
    return [scrollView.subviews firstObject];
}
- (void)scrollViewDidScroll:(UIScrollView *)scrollView
{
    //只要用户滚动scrollView，都会调用这个方法＊＊＊＊＊*********重要的
    NSLog(@"任何偏移量的改变都会调用这个方法");
}
- (void)scrollViewWillBeginDragging:(UIScrollView *)scrollView
{
    //用户将要开始拖动scrollView的时候
    NSLog(@"开始拖动");
}
- (void)scrollViewDidEndDragging:(UIScrollView *)scrollView willDecelerate:(BOOL)decelerate
{
    NSLog(@"结束拖动");
}
- (void)scrollViewWillBeginDecelerating:(UIScrollView *)scrollView
{
    
    NSLog(@"开始减速");
}
- (void)scrollViewDidEndDecelerating:(UIScrollView *)scrollView
{
    NSLog(@"结束减速");
}
- (void)didReceiveMemoryWarning
{
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}
/*
#pragma mark - Navigation
// In a storyboard-based application, you will often want to do a little preparation before navigation
- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender
{
    // Get the new view controller using [segue destinationViewController].
    // Pass the selected object to the new view controller.
}
*/
@end