IOS使用UIImageView显示gif动画的例子

其中用到了两个开源代码

1.SDWebImage  异步读取图片数据
2.SCGifExample  gif动画控件

此工程在SCGifExample的基础上修改

最近SDWebImage刚升级，我也借此修改了我的代码，
从中摘出gif部分与大家分享


图片缩放部分我还是用的手势，感觉以下方法不怎么好用，如果大家有更好的算法请分享
图片缩放效果请在真机上使用

 - (UIView *)viewForZoomingInScrollView:(UIScrollView *)scrollView
 {
     return imageView;
 }

 - (void)scrollViewDidZoom:(UIScrollView *)scrollView
 {
     imageView.center = scrollView.center;

     if (imageView.frame.origin.x < 0)
     {
         setFrameX(imageView, 0);
     }
     if (imageView.frame.origin.y < 0)
     {
         setFrameY(imageView, 0);
     }
 }

SDWebImage内部其实也可以实现动态图片读取，我项目紧没时间改，有兴趣的可以自己改改
返回Imge时返回imageArray就可以，代码可以学习SCGifExample的实现

SDWebImage增加了4个SDWebImageManagerDelegate函数

- (void)webImageManager:(SDWebImageManager *)imageManager ActivityIndicatorView:(UIActivityIndicatorView *)activityIndicatorView didFailWithError:(NSError *)error;
- (void)webImageManager:(SDWebImageManager *)imageManager ActivityIndicatorView:(UIActivityIndicatorView *)activityIndicatorView didFinishWithImage:(UIImage *)image drawRoundedRect:(BOOL)bDraw;

// SDImageCache中有数据
- (void)webImageManager:(SDWebImageManager *)imageManager ActivityIndicatorView:(UIActivityIndicatorView *)activityIndicatorView  FileName:(NSString*)fileName didFinishWithImage:(UIImage *)image drawRoundedRect:(BOOL)bDraw;
// SDImageCache中无数据，SDWebImageDownloader下载获得
- (void)webImageManager:(SDWebImageManager *)imageManager ActivityIndicatorView:(UIActivityIndicatorView *)activityIndicatorView  ImageData:(NSData *)imageData didFinishWithImage:(UIImage *)image drawRoundedRect:(BOOL)bDraw;

(UIActivityIndicatorView *)activityIndicatorView 用于显示下载状态
在ImageView调用SDWebImageManager时加载

typedef enum
{
    SDWebImageRetryFailed = 1 << 0,
    SDWebImageLowPriority = 1 << 1,
    SDWebImageCacheMemoryOnly = 1 << 2,
    SDWebImageRoundedRect = 1 << 3
} SDWebImageOptions;
中增加了SDWebImageRoundedRect用于标示是否显示圆角图片

SCGifExample增加了2个函数

- (BOOL)setGIFFile:(NSString*)gifFilePath;
- (BOOL)setGIFData:(NSData*)gifImageData;

状态栏和工具条我没有做完，状态栏最好自定义

2012-03-16:
发现了一个问题，请自行修改
UIActivityIndicatorView有可能会重复创建，会的就不需要往下看了，我只是打了个补丁

修改如下：

 - (void)setImageWithURL:(NSURL *)url placeholderImage:(UIImage *)placeholder options:(SDWebImageOptions)options
 {
     SDWebImageManager *manager = [SDWebImageManager sharedManager];

     // Remove in progress downloader from queue
     [manager cancelForDelegate:self];

     self.image = placeholder;

     if (url)
     {
         UIActivityIndicatorView *progressInd = (UIActivityIndicatorView *)[self viewWithTag:30326];

         if (progressInd == nil)
         {
             progressInd = [[UIActivityIndicatorView alloc] initWithActivityIndicatorStyle:UIActivityIndicatorViewStyleWhiteLarge];
             progressInd.tag = 30326;
             [progressInd startAnimating];
             [self addSubview:progressInd size:CGSizeMake(37, 37)];

             [progressInd release];
         }

         //[manager downloadWithURL:url delegate:self options:options];
         [manager downloadWithURL:url ActivityIndicatorView:progressInd delegate:self options:options];
     }
 }

3月23日：
SDWebImage内部有点问题，当网址链接不是image时照样返回image图片数据
可以在
NS_INLINE UIImage *SDScaledImageForPath(NSString *path, NSData *imageData)
函数中增加对imageData的判断，是否为图片数据
非时返回nil

- (void)connectionDidFinishLoading:(NSURLConnection *)aConnection
函数中再判断其值返回delegate 调用 performSelector:@selector(imageDownloader:didFailWithError:)

下载地址：点击下载

新版：点击下载

最近SDWebImage改动比较频繁，我把代码也整合了一下，简化了delegate

增加了Button部分的修改，可以设置前景背景不同状态的图片

我不做工程了，只上传SDWebImage部分

下载：SDWebImage_2.6_b78238802d.zip

好久没跟这个了发现新版SDWebImage有个大问题，会随机的阻塞下载线程导致图片不能下载成功，

老版本的那个没有问题，增加gif即可

加个gif算法：

sd_isGIF在新版SDWebImage里是有的

 - (BOOL)animatedGIFWithData:(NSData *)data
 {
     if (!data)
     {
         return NO;
     }

     if (![data sd_isGIF])
     {
         return NO;
     }

     CGImageSourceRef source = CGImageSourceCreateWithData(( CFDataRef)data, NULL);

     size_t count = CGImageSourceGetCount(source);
     NSMutableArray *images = [NSMutableArray array];

     NSTimeInterval duration = 0.0f;

     for (size_t i = 0; i < count; i++)
     {
         CGImageRef image = CGImageSourceCreateImageAtIndex(source, i, NULL);

         NSDictionary *frameProperties = CFBridgingRelease(CGImageSourceCopyPropertiesAtIndex(source, i, NULL));
         duration += [[[frameProperties objectForKey:(NSString*)kCGImagePropertyGIFDictionary] objectForKey:(NSString*)kCGImagePropertyGIFDelayTime] doubleValue];

         [images addObject:[UIImage imageWithCGImage:image scale:[UIScreen mainScreen].scale orientation:UIImageOrientationUp]];

         CGImageRelease(image);
     }

     CFRelease(source);

     if (!duration)
     {
         duration = (1.0f/10.0f)*count;
     }

     if (images.count > 0)
     {
         [self setImage:[images objectAtIndex:0]];
         [self setAnimationImages:images];

         [self setAnimationDuration:duration];
         [self setAnimationRepeatCount:0];
         [self startAnimating];

         return YES;
     }

     return NO;
 }