UIScrollView 如何实现多图 缩放

建了一个主ScrollView   
然后建了三个子ScrollView  加载在主ScrollView上，   如何实现多图缩放呢，，，我发的这个方法只能实现第一个图片的缩放
#import "MainViewController.h"
@interface MainViewController ()<UIScrollViewDelegate>@property (nonatomic, retain) UIScrollView *myscroll1;
@property (nonatomic, retain) UIScrollView *myscroll2;
@property (nonatomic, retain) UIScrollView *myscroll3;@end@implementation MainViewController-(void)dealloc
{
    [_myscroll1 release];
    [_myscroll2 release];
    [_myscroll3 release];
    [super dealloc];
}- (void)viewDidLoad {
    [super viewDidLoad];
    // Do any additional setup after loading the view.
    
    
    //主scrollView
    UIScrollView *myscroll = [[UIScrollView alloc] initWithFrame:CGRectMake(0, 0, 375, 667)];
    myscroll.backgroundColor = [UIColor yellowColor];
    [self.view addSubview:myscroll];
    [myscroll release];
    
    myscroll.contentSize = CGSizeMake(3 * 375, 667);
    
    myscroll.pagingEnabled = YES;
    
    //第一个scrollView
    self.myscroll1 = [[UIScrollView alloc] initWithFrame:CGRectMake(0, 0, 375, 667)];
    self.myscroll1.backgroundColor = [UIColor redColor];
    [myscroll addSubview:self.myscroll1];
    self.myscroll1.maximumZoomScale = 2.0;
    self.myscroll1.minimumZoomScale = 0.5;
    self.myscroll1.delegate = self;
    [self.myscroll1 release];
    
    UIImageView *imageView1 = [[UIImageView alloc] initWithFrame:CGRectMake(0, 0, 375, 667)];
    imageView1.image = [UIImage imageNamed:@"0.jpg"];
    [self.myscroll1 addSubview:imageView1];
    [imageView1 release];
    
    
    //第二个scrollView
    self.myscroll2 = [[UIScrollView alloc] initWithFrame:CGRectMake(375, 0, 375, 667)];
    self.myscroll2.backgroundColor = [UIColor redColor];
    [myscroll addSubview:self.myscroll2];
    self.myscroll2.maximumZoomScale = 2.0;
    self.myscroll2.minimumZoomScale = 0.5;
    self.myscroll2.delegate = self;
    [self.myscroll2 release];
    
    UIImageView *imageView2 = [[UIImageView alloc] initWithFrame:CGRectMake(0, 0, 375, 667)];
    imageView2.image = [UIImage imageNamed:@"1.jpg"];
    [self.myscroll2 addSubview:imageView2];
    [imageView2 release];
    
    //第二个scrollView
    self.myscroll3 = [[UIScrollView alloc] initWithFrame:CGRectMake(750, 0, 375, 667)];
    self.myscroll3.backgroundColor = [UIColor redColor];
    [myscroll addSubview:self.myscroll3];
    self.myscroll3.maximumZoomScale = 2.0;
    self.myscroll3.minimumZoomScale = 0.5;
    self.myscroll3.delegate = self;
    [self.myscroll3 release];
    
    UIImageView *imageView3 = [[UIImageView alloc] initWithFrame:CGRectMake(0, 0, 375, 667)];
    imageView3.image = [UIImage imageNamed:@"2.jpg"];
    [self.myscroll3 addSubview:imageView3];
    [imageView3 release];
    
    
    
    
    
    
    
}
- (UIView *)viewForZoomingInScrollView:(UIScrollView *)scrollView
{
    //缩放scrollView
    //2.指定一个scrollView的子视图，跟着scrollView放大缩小
    
    //有两点需要注意的
    //1.scrollView放大缩小之后，contentSize会和子视图frame的size一样大
    //2.scrollView的滚动条也是两个视图，都是UIImageView，会始终处在显示的最上面（也就是子视图数组的最后面 ）
       
    
    return [self.myscroll1.subviews firstObject];
    
}