iOS图片缩小放大scollView实现代码

    //  ImageDetailCon.h  
    //  
    //  

    #import <UIKit/UIKit.h>  
    @interface ImageDetailCon : UIViewController<UIScrollViewDelegate>    //需要使用 对应的 协议  
    @property(strong,nonatomic)NSURL *imageURL;//给外界的接口,外界传值给ImageDetailCon  *vc;,然后present出来即可  
    @end  
    //  
    //  ImageDetailCon.m  
    //  

    #import "ImageDetailCon.h"  
    #import <UIImageView+AFNetworking.h>//使用afnetworking框架  
    @interface ImageDetailCon ()  
    {  
        UIScrollView *scrollView;  
        UIImageView *imageView;  
    }  
    @end  

    @implementation ImageDetailCon  
    - (void)viewDidLoad  
    {  
        [super viewDidLoad];  
        scrollView=[[UIScrollView alloc]initWithFrame:self.view.bounds];  
        scrollView.maximumZoomScale=5.0;//图片的放大倍数  
        scrollView.minimumZoomScale=1.0;//图片的最小倍率  
        scrollView.contentSize=CGSizeMake(self.view.bounds.size.width*1.5, self.view.bounds.size.height*1.5);  
        scrollView.delegate=self;  
        imageView=[[UIImageView alloc]initWithFrame:self.view.bounds];  
        [imageView setImageWithURL:self.imageURL placeholderImage:[UIImage imageNamed:@"Fav_Img_Download"]];  
        [scrollView addSubview:imageView];  
        [self.view addSubview:scrollView];  
        imageView.userInteractionEnabled=YES;//注意:imageView默认是不可以交互,在这里设置为可以交互  
        UITapGestureRecognizer *tap=[[UITapGestureRecognizer alloc]initWithTarget:self action:@selector(tapImage:)];  
        tap.numberOfTapsRequired=1;//单击  
        tap.numberOfTouchesRequired=1;//单点触碰  
        [imageView addGestureRecognizer:tap];  
        UITapGestureRecognizer *doubleTap=[[UITapGestureRecognizer alloc]initWithTarget:self action:@selector(doubleTap:)];  
        doubleTap.numberOfTapsRequired=2;//避免单击与双击冲突  
        [tap requireGestureRecognizerToFail:doubleTap];  
        [imageView addGestureRecognizer:doubleTap];  
        imageView.contentMode=UIViewContentModeScaleAspectFit;  

    }  
    -(UIView *)viewForZoomingInScrollView:(UIScrollView *)scrollView  //委托方法,必须设置  delegate  
    {  
        return imageView;//要放大的视图  
    }  

    -(void)doubleTap:(id)sender  
    {  
        scrollView.zoomScale=2.0;//双击放大到两倍  
    }  
    - (IBAction)tapImage:(id)sender  
    {  
        [self dismissViewControllerAnimated:YES completion:nil];//单击图像,关闭图片详情(当前图片页面)  
    }  
    @end