给原生的 UIImageView 添加类别来支持 GIF 播放

来源：互联网发布：湖北金融数据网编辑：程序博客网时间：2024/05/01 20:37

1.新建一个 UIImageView 的类别

2.解析 GIF ，获得 GIF 的信息

#pragma mark -- 解析 DGIF-(void)gifWithUrl:(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 文件中的图片个数    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 array];    //存放每一帧播放的时间    NSMutableArray *timeArray = [NSMutableArray array];    //存放每张图片的宽度（一般在一个 gif 文件中，所有文件的尺寸都一样）    NSMutableArray *widthArray = [NSMutableArray array];    //存放每张图片的高度    NSMutableArray * heightArray = [NSMutableArray array];    //遍历    for(size_t i = 0;i < count; i++){    //获取图片信息        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);        NSLog(@"%@",info);        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]];    }    dataBlock(imageArray,timeArray,allTime,widthArray,heightArray);}

3.加载 GIF

timingFunction: 控制动画运行的节奏

kCAMediaTimingFunctionLinear（线性）：匀速，给你一个相对静态的感觉
kCAMediaTimingFunctionEaseIn（渐进）：动画缓慢进入，然后加速离开
kCAMediaTimingFunctionEaseOut（渐出）：动画全速进入，然后减速的到达目的地
kCAMediaTimingFunctionEaseInEaseOut（渐进渐出）：动画缓慢的进入，中间加速，然后减速的到达目的地。这个是默认的动画行为

#pragma mark -- 加载 GIF- (void)cc_setImage:(NSURL *)imageUrl {    __weak id _self = self;    [self gifWithUrl:imageUrl returnData:^(NSArray<UIImage *> *imageArray, NSArray<NSNumber *> *timeArray, CGFloat totalTime, NSArray<NSNumber *> *widths, NSArray<NSNumber *> *heights) {               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:kCAMediaTimingFunctionEaseInEaseOut]];        //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"];    }];}}

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