简易图片浏览器【可缩放图片，滑动后恢复正常】

AppDelegate.h

#import "AppDelegate.h"#import "RootViewController.h"@implementation AppDelegate- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions{    self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];    // Override point for customization after application launch.    self.window.backgroundColor = [UIColor whiteColor];    [self.window makeKeyAndVisible];        RootViewController *rootCtrl = [[RootViewController alloc] init];        UINavigationController *navCtrl = [[UINavigationController alloc] initWithRootViewController:rootCtrl];        NSMutableArray *mutArrary = [[NSMutableArray alloc] init];        for (int i=0; i<5; i++)    {        NSString *imgName = [NSString stringWithFormat:@"%d.JPG",i];        UIImage *image = [UIImage imageNamed:imgName];        [mutArrary addObject:image];    }        rootCtrl.images = mutArrary;        self.window.rootViewController = navCtrl;        return YES;}@end

RootViewController.h

@interface RootViewController : UIViewController<UIScrollViewDelegate>{    NSInteger _index;}@property(nonatomic, retain)NSArray *images;    //存放显示的图片

RootViewController.m

#import "RootViewController.h"#import "PhotoScrollView.h"@interface RootViewController ()@end@implementation RootViewController- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil{    self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];    if (self) {        // Custom initialization    }    return self;}- (void)viewDidLoad{    [super viewDidLoad];    //创建滚动视图    UIScrollView *scrollView = [[UIScrollView alloc] initWithFrame:CGRectMake(0, 0, 340, 480)];    //隐藏水平滚动条    scrollView.showsHorizontalScrollIndicator = NO;    scrollView.backgroundColor = [UIColor blackColor];    scrollView.delegate = self;    //设置分页效果    scrollView.pagingEnabled = YES;        //设置内容尺寸    scrollView.contentSize = CGSizeMake(340*_images.count, 480);    [self.view addSubview:scrollView];        for (int i=0; i<self.images.count; i++) {        PhotoScrollView *photoView = [[PhotoScrollView alloc] initWithFrame:CGRectMake(340*i, 0, 320, 480)];        photoView.tag = i + 100;        //传值        photoView.image =_images[i];        [scrollView addSubview:photoView];    }    }#pragma mark - UIScrollView delegate- (void)scrollViewDidEndDecelerating:(UIScrollView *)scrollView {    //1.获取当前的页数    int currentPage = scrollView.contentOffset.x/340;        //2.还原以前的缩放试图    if (currentPage != _index) {        //取得视图        int tag = _index + 100;        PhotoScrollView *view = (PhotoScrollView *)[scrollView viewWithTag:tag];                //还原        [view setZoomScale:1];    }            //3.记录当前的页数    _index = currentPage;}/*#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

PhotoScrollView.h

@interface PhotoScrollView : UIScrollView<UIScrollViewDelegate>{    UIImageView *_imageView;}@property(nonatomic, retain)UIImage *image;

PhotoScrollView.m

#import "PhotoScrollView.h"@implementation PhotoScrollView- (id)initWithFrame:(CGRect)frame{    self = [super initWithFrame:frame];    if (self) {        _imageView = [[UIImageView alloc] initWithFrame:self.bounds];                //数据不能在这里设置//        _imageView.image = _image;                [self addSubview:_imageView];                //设置最大放大倍数        self.maximumZoomScale = 2.0;        //设置最小缩小倍数        self.minimumZoomScale = .5;                //隐藏滚动条        self.showsHorizontalScrollIndicator = NO;        self.showsVerticalScrollIndicator = NO;                //设置代理        self.delegate = self;                //添加手势        UITapGestureRecognizer *tap = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(tapActoin:)];        tap.numberOfTapsRequired = 2;        [self addGestureRecognizer:tap];            }    return self;}//手势响应事件- (void)tapActoin:(UITapGestureRecognizer *)tap {    if (self.zoomScale > 1) {        //缩小        [self setZoomScale:1 animated:YES];    }else {        //放大        [self setZoomScale:2 animated:YES];    }    }- (void)setImage:(UIImage *)image {    _image = image;        _imageView.image = _image;}#pragma mark - UIScrollView delegate- (UIView *)viewForZoomingInScrollView:(UIScrollView *)scrollView {    return _imageView;}@end