UIScrollView实现缩放

#import "ViewController.h"

@interface ViewController () <UIScrollViewDelegate>
{
UIImageView *imageView;
}
@end

@implementation ViewController

- (void)viewDidLoad {
[super viewDidLoad];

UIScrollView *scrollview = [[UIScrollView alloc] initWithFrame:self.view.bounds];
//设置最大最小缩放比例
scrollview.minimumZoomScale = 0.5;
scrollview.maximumZoomScale = 2;
//设置代理
scrollview.delegate = self;

imageView = [[UIImageView alloc] initWithFrame:self.view.bounds];
imageView.image = [UIImage imageNamed:@"0.JPG"];
imageView.userInteractionEnabled = YES;

[scrollview addSubview:imageView];
[self.view addSubview:scrollview];
}
//实现代理方法,返回缩放后的视图
-(UIView *)viewForZoomingInScrollView:(UIScrollView *)scrollView {

return imageView;
}
@end