浅析IOS中播放gif动态图的方法

//要引入ImageIO库#import <ImageIO/ImageIO.h>//解析gif文件数据的方法 block中会将解析的数据传递出来-(void)getGifImageWithUrk:(NSURL *)url    returnData:(void(^)(NSArray<UIImage *> * imageArray,        NSArray<NSNumber *>*timeArray,        CGFloat totalTime,        NSArray<NSNumber *>* widths,        NSArray<NSNumber *>* heights))dataBlock{ //通过文件的url来将gif文件读取为图片数据引用 CGImageSourceRef source = CGImageSourceCreateWithURL((CFURLRef)url, NULL); //获取gif文件中图片的个数 size_t count = CGImageSourceGetCount(source); //定义一个变量记录gif播放一轮的时间 float allTime=0; //存放所有图片 NSMutableArray * imageArray = [[NSMutableArray alloc]init]; //存放每一帧播放的时间 NSMutableArray * timeArray = [[NSMutableArray alloc]init]; //存放每张图片的宽度 （一般在一个gif文件中，所有图片尺寸都会一样） NSMutableArray * widthArray = [[NSMutableArray alloc]init]; //存放每张图片的高度 NSMutableArray * heightArray = [[NSMutableArray alloc]init]; //遍历 for (size_t i=0; i<count; i++) {  CGImageRef image = CGImageSourceCreateImageAtIndex(source, i, NULL);  [imageArray addObject:(__bridge UIImage *)(image)];  CGImageRelease(image);  //获取图片信息  NSDictionary * info = (__bridge NSDictionary*)CGImageSourceCopyPropertiesAtIndex(source, i, NULL);  CGFloat width = [[info objectForKey:(__bridge NSString *)kCGImagePropertyPixelWidth] floatValue];  CGFloat height = [[info objectForKey:(__bridge NSString *)kCGImagePropertyPixelHeight] floatValue];  [widthArray addObject:[NSNumber numberWithFloat:width]];  [heightArray addObject:[NSNumber numberWithFloat:height]];  NSDictionary * timeDic = [info objectForKey:(__bridge NSString *)kCGImagePropertyGIFDictionary];  CGFloat time = [[timeDic objectForKey:(__bridge NSString *)kCGImagePropertyGIFDelayTime]floatValue];  allTime+=time;  [timeArray addObject:[NSNumber numberWithFloat:time]];  CFRelease(info); } CFRelease(source); dataBlock(imageArray,timeArray,allTime,widthArray,heightArray);}

-(void)yh_setImage:(NSURL *)imageUrl{  __weak id __self = self;  [self getGifImageWithUrk:imageUrl returnData:^(NSArray<UIImage *> *imageArray, NSArray<NSNumber *> *timeArray, CGFloat totalTime, NSArray<NSNumber *> *widths, NSArray<NSNumber *> *heights) {   //添加帧动画   CAKeyframeAnimation *animation = [CAKeyframeAnimation animationWithKeyPath:@"contents"];   NSMutableArray * times = [[NSMutableArray alloc]init];   float currentTime = 0;   //设置每一帧的时间占比   for (int i=0; i<imageArray.count; i++) {    [times addObject:[NSNumber numberWithFloat:currentTime/totalTime]];    currentTime+=[timeArray[i] floatValue];   }   [animation setKeyTimes:times];   [animation setValues:imageArray];   [animation setTimingFunction:[CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionLinear]];   //设置循环   animation.repeatCount= MAXFLOAT;   //设置播放总时长   animation.duration = totalTime;   //Layer层添加   [[(UIImageView *)__self layer]addAnimation:animation forKey:@"gifAnimation"];  }];}

 UIImageView * imageView = [[UIImageView alloc]initWithFrame:CGRectMake(0,0 , 320, 200)]; NSURL * url = [[NSURL alloc]initFileURLWithPath:[[NSBundle mainBundle] pathForResource:imageName ofType:nil]]; [imageView yh_setImage:url]; [self.view addSubview:imageView];

 //读取gif数据   NSData *gifData = [NSData dataWithContentsOfURL:imageUrl];  UIWebView *webView = [[UIWebView alloc] initWithFrame:CGRectMake(0, 0, self.frame.size.width, self.frame.size.height)];  //取消回弹效果  webView.scrollView.bounces=NO;  webView.backgroundColor = [UIColor clearColor];  //设置缩放模式  webView.scalesPageToFit = YES;  //用webView加载数据  [webView loadData:gifData MIMEType:@"image/gif" textEncodingName:nil baseURL:nil];