// 用户开始拖拽时调用
- (void)scrollViewWillBeginDragging:(UIScrollView *)scrollView;// 滚动到某个位置时调用
- (void)scrollViewDidScroll:(UIScrollView *)scrollView;// 用户结束拖拽时调用
- (void)scrollViewDidEndDragging:(UIScrollView *)scrollView willDecelerate:(BOOL)decelerate;

/****属性****/
//缩小的对小比例
@property(nonatomic) CGFloat minimumZoomScale;//放大的最大比例
@property(nonatomic) CGFloat maximumZoomScale;    /****方法****/
//缩放时调用
- (UIView *)viewForZoomingInScrollView:(UIScrollView *)scrollView;//开始缩放的时候调用
- (void)scrollViewWillBeginZooming:(UIScrollView *)scrollView withView:(UIView *)view//正在缩放的时候调用
- (void)scrollViewDidZoom:(UIScrollView *)scrollView

#import "ViewController.h"@interface ViewController ()<UIScrollViewDelegate>
/***UIScrollView*/
@property(nonatomic,strong)UIScrollView *scrollView;/***  UIImageView*/
@property(nonatomic,strong)UIImageView *imageView;
@end@implementation ViewController
- (void)viewDidLoad {//2.设置 UIImageView
 UIImage *image = [UIImage imageNamed:@"scroll.jpg"];self.imageView.image = image;//2.1 设置图片范围CGFloat imageH = image.size.height;CGFloat imageW = image.size.width;CGFloat imageX = 0;CGFloat imageY = 0;self.imageView.frame = CGRectMake(imageX, imageY, imageW, imageH);//3 设置UIScrollView 属性//3.2 设置UIScrollView内容的尺寸，滚动范围self.scrollView.contentSize=CGSizeMake(imageW, imageH);//3.2 设置UIScrollView的4周增加额外的滚动区域CGFloat distance = 100.0f;self.scrollView.contentInset = UIEdgeInsetsMake(distance, distance, distance, distance);//3.3 设置弹簧效果self.scrollView.bounces = YES;//3.4 设置滚动不显示self.scrollView.showsHorizontalScrollIndicator=NO;self.scrollView.showsVerticalScrollIndicator=NO;//4 UIImageView 添加到 UIScrollView 中
    [self.scrollView addSubview:self.imageView];//5 UIScrollView
    [self.view addSubview:self.scrollView];//6 设置代理self.scrollView.delegate = self;//7 缩放self.scrollView.minimumZoomScale=0.2f;self.scrollView.maximumZoomScale=2.0f;}#pragma mark 代理方法
// 用户开始拖拽时调用
- (void)scrollViewWillBeginDragging:(UIScrollView *)scrollView
{NSLog(@"开始拖拽");
}// 滚动到某个位置时调用
- (void)scrollViewDidScroll:(UIScrollView *)scrollView
{NSLog(@"拖拽中");
}// 用户结束拖拽时调用
- (void)scrollViewDidEndDragging:(UIScrollView *)scrollView willDecelerate:(BOOL)decelerate
{NSLog(@"结束拖拽");
}#pragma mark 缩放
/***  缩放结束时调用**  @param scrollView <#scrollView description#>**  @return <#return value description#>*/
- (UIView *)viewForZoomingInScrollView:(UIScrollView *)scrollView
{NSLog(@"开始缩放");return self.imageView;
}/***  缩放过程中调用**  @param scrollView <#scrollView description#>*/
- (void)scrollViewDidZoom:(UIScrollView *)scrollView
{NSLog(@"正在缩放");
}/***  缩放结束时调用**  @param scrollView <#scrollView description#>*  @param view       <#view description#>*  @param scale      <#scale description#>*/
- (void)scrollViewDidEndZooming:(UIScrollView *)scrollView withView:(UIView *)view atScale:(CGFloat)scale
{NSLog(@"缩放结束");
}#pragma mark 属性get方法- (UIScrollView *)scrollView
{if (!_scrollView) {_scrollView = [[UIScrollView alloc] initWithFrame:self.view.frame];}return _scrollView;
}- (UIImageView *)imageView
{if (!_imageView) {_imageView = [[UIImageView alloc] init];}return _imageView;
}@end

//使用一个ScrollView
//创建一个UIScrollView
CGRectframe = CGRectMake( 0, 0, 200, 200);
scrollView= [[UIScrollView alloc] initWithFrame: frame];//添加子视图（框架可以超过scroll view的边界）
frame= CGRectMake( 0, 0, 500, 500);
myImageView= [[UIImageView alloc] initWithFrame: frame];
[scrollViewaddSubview:myImageView];//设置内容尺寸
scrollView.contentSize= CGSize(500,500);