IOS 图片浏览放大的简单实现

头：

#import <UIKit/UIKit.h>

@interface ImageBrowserViewController : UIViewController

@property (nonatomic,retain) NSArray *images;

@property (nonatomic) int currentIndex;
@end

实现：

#import "ImageBrowserViewController.h"

@interface ImageBrowserViewController ()<UIScrollViewDelegate>

@property (weak, nonatomic) IBOutlet UIScrollView *scrollView; //xib 文件中的控件
- (IBAction)backAction:(id)sender; //退出事件

@end

@implementation ImageBrowserViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    
    //_images = @[@"https://ss3.bdstatic.com/lPoZeXSm1A5BphGlnYG/skin/482.jpg",
    //           @"https://ss2.bdstatic.com/kfoZeXSm1A5BphGlnYG/skin/273.jpg",
    //            @"https://ss1.bdstatic.com/kvoZeXSm1A5BphGlnYG/skin_zoom/492.jpg"];
    //_currentIndex=0;
    
    [self initScrollView];
    
    
    
    // Do any additional setup after loading the view from its nib.
}

- (void)didReceiveMemoryWarning {
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}


-(void)initScrollView{
    int imagecount = [_images count];
    _scrollView.pagingEnabled =true;
    _scrollView.contentSize = CGSizeMake(_scrollView.frame.size.width*imagecount, _scrollView.frame.size.height);
    
    
    for (int i=0; i<imagecount; i++) {
        
        UIScrollView *subscrollview = [[UIScrollView alloc] initWithFrame:CGRectMake(i*_scrollView.frame.size.width, 0, _scrollView.frame.size.width, _scrollView.frame.size.height)];
        subscrollview.tag = i+100;
        //设置实现缩放 //设置代理scrollview的代理对象
        subscrollview.delegate=self;
        //设置最大伸缩比例
        subscrollview.maximumZoomScale=10.0;
        //设置最小伸缩比例
        subscrollview.minimumZoomScale=1;
        
        UIImageView *imageview = [[UIImageView alloc] initWithFrame:CGRectMake(5, 0, _scrollView.frame.size.width-10, _scrollView.frame.size.height)];
        imageview.tag = 1;
        imageview.contentMode = UIViewContentModeScaleAspectFit;
        [imageview sd_setImageWithURL:_images[i] placeholderImage:[UIImage imageNamed:@"photo"]];
        //[imageview setImage:[UIImage imageWithData:[NSData dataWithContentsOfURL:[ NSURL URLWithString:_images[i]]]]];
        
        [subscrollview addSubview:imageview];
        [_scrollView addSubview:subscrollview];
    }
    
    if (_currentIndex>0) {
        [_scrollView setContentOffset:CGPointMake(_scrollView.frame.size.width*_currentIndex, 0)];
    }
    
}

-(void)scrollViewDidZoom:(UIScrollView *)scrollView
{
    if(scrollView.zoomScale == 1){
        _scrollView.scrollEnabled = true;
    }else{
        _scrollView.scrollEnabled = false;
    };
    NSLog(@"%f", scrollView.zoomScale);
}

//告诉scrollview要缩放的是哪个子控件
-(UIView *)viewForZoomingInScrollView:(UIScrollView *)scrollView
{
    return [scrollView viewWithTag:1];
}

/*
#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.
}
*/

- (IBAction)backAction:(id)sender {
    [self dismissViewControllerAnimated:true completion:nil];
}
@end

调用：
ImageBrowserViewController *vc  = [[ImageBrowserViewController alloc] initWithNibName:@"ImageBrowserViewController" bundle:nil];
    
    vc.images =  picArray ;
    vc.currentIndex = 0;
    
    [self presentViewController:vc animated:true completion:nil];