iOS开发之UIScrollView控件代码实现图片缩放功能
#import "YYViewController.h" @interface YYViewController (){ UIScrollView *_scrollview; UIImageView *_imageview; } @end @implementation YYViewController - (void)viewDidLoad { [super viewDidLoad]; //1添加 UIScrollView //设置 UIScrollView的位置与屏幕大小相同 _scrollview=[[UIScrollView alloc]initWithFrame:self.view.bounds]; [self.view addSubview:_scrollview]; //2添加图片 //有两种方式 //(1)一般方式 // UIImageView *imageview=[[UIImageView alloc]init]; // UIImage *image=[UIImage imageNamed:@"minion"]; // imageview.image=image; // imageview.frame=CGRectMake(0, 0, image.size.width, image.size.height); //(2)使用构造方法 UIImage *image=[UIImage imageNamed:@"minion"]; _imageview=[[UIImageView alloc]initWithImage:image]; //调用initWithImage:方法,它创建出来的imageview的宽高和图片的宽高一样 [_scrollview addSubview:_imageview]; //设置UIScrollView的滚动范围和图片的真实尺寸一致 _scrollview.contentSize=image.size; //设置实现缩放 //设置代理scrollview的代理对象 _scrollview.delegate=self; //设置最大伸缩比例 _scrollview.maximumZoomScale=2.0; //设置最小伸缩比例 _scrollview.minimumZoomScale=0.5; } //告诉scrollview要缩放的是哪个子控件 -(UIView *)viewForZoomingInScrollView:(UIScrollView *)scrollView { return _imageview; } @end