UIScrollView缩放代理方法的使用以及注意事项？

1、1.声明控件

#import "ViewController.h"

@interface ViewController ()<UIScrollViewDelegate>

@property(nonatomic,strong) UIScrollView *scrollView;

@property(nonatomic,strong)UIImageView * imageView;

@end

@implementation ViewController

- (void)viewDidLoad {

    [super viewDidLoad];

    [self createScrollView];

}

2、2.控件的初始化

- (void)createScrollView

{

    _scrollView = [[UIScrollView alloc] init];

    _scrollView.backgroundColor = [UIColor yellowColor];

    _scrollView.delegate = self;

    _scrollView.frame = CGRectMake(0, 60, self.view.frame.size.width, 260);

    [self.view addSubview:_scrollView];

    // 设置缩放的范围

    self.scrollView.minimumZoomScale = 0.2;

    self.scrollView.maximumZoomScale = 1.2;

    _imageView = [[UIImageView alloc] init];

    _imageView.frame = CGRectMake(0, 0, 80, 80);

    _imageView.center = _scrollView.center;

    [self.view addSubview:_imageView];

    _imageView.image = [UIImage imageNamed:@"blue.jpg"];

}

3、3.UIScrollView的缩放代理方法的实现

#pragma mark - 当用户缩放的时候，要设置绽放哪个View要被缩放

-(UIView *)viewForZoomingInScrollView:(UIScrollView *)scrollView

{

    return self.imageView;

}

#pragma mark - 当scrollView缩放时，调用该方法。在缩放过程中，会多次调用

- (void)scrollViewDidZoom:(UIScrollView *)scrollView{

    NSLog(@"scrollViewDidScroll");

    float value=scrollView.zoomScale;

    NSLog(@"%f",value);

}