ios使用SDWebImage加载大图时，内存泄漏的问题

素颜马尾好姑娘i 2022-06-08 23:27 617阅读 0赞

第一步：

在UIImage+MultiFormat 中增加方法

+(UIImage *)compressImageWith:(UIImage *)image
    {
        float imageWidth = image.size.width;
        float imageHeight = image.size.height;
        float width = 640;
        float height = image.size.height/(image.size.width/width);
        
        float widthScale = imageWidth /width;
        float heightScale = imageHeight /height;
        
        // 创建一个bitmap的context
        // 并把它设置成为当前正在使用的context
        UIGraphicsBeginImageContext(CGSizeMake(width, height));
        
        if (widthScale > heightScale) {
            [image drawInRect:CGRectMake(0, 0, imageWidth /heightScale , height)];
        }
        else {
            [image drawInRect:CGRectMake(0, 0, width , imageHeight /widthScale)];
        }
        
        // 从当前context中创建一个改变大小后的图片
        UIImage *newImage = UIGraphicsGetImageFromCurrentImageContext();
        // 使当前的context出堆栈
        UIGraphicsEndImageContext();
        
        return newImage;
        
    }

第二布：  在UIImage+MultiFormat 中  \+( UIImage  \*)sd\_imageWithData:( NSData  \*)data 这个方法中增加代码

+ (UIImage *)sd_imageWithData:(NSData *)data {
        if (!data) {
            return nil;
        }
        
        UIImage *image;
        NSString *imageContentType = [NSData sd_contentTypeForImageData:data];
        if ([imageContentType isEqualToString:@"image/gif"]) {
            image = [UIImage sd_animatedGIFWithData:data];
        }
    #ifdef SD_WEBP
        else if ([imageContentType isEqualToString:@"image/webp"])
        {
            image = [UIImage sd_imageWithWebPData:data];
        }
    #endif
        else {
            image = [[UIImage alloc] initWithData:data];
    //增加的代码
            if (data.length/1024 > 128) {
                image = [self compressImageWith:image];
            }
    //
            UIImageOrientation orientation = [self sd_imageOrientationFromImageData:data];
            if (orientation != UIImageOrientationUp) {
                image = [UIImage imageWithCGImage:image.CGImage
                                            scale:image.scale
                                      orientation:orientation];
            }
        }
    
    
        return image;
    }

第三步：在SDWebImageDownloaderOperation.m 的  \-( void )connectionDidFinishLoading:( NSURLConnection  \*)aConnection 方法中增加代码

-(void)connectionDidFinishLoading:(NSURLConnection *)aConnection {
        SDWebImageDownloaderCompletedBlock completionBlock = self.completedBlock;
        @synchronized(self) {
            CFRunLoopStop(CFRunLoopGetCurrent());
            self.thread = nil;
            self.connection = nil;
            dispatch_async(dispatch_get_main_queue(), ^{
                [[NSNotificationCenter defaultCenter] postNotificationName:SDWebImageDownloadStopNotification object:self];
                [[NSNotificationCenter defaultCenter] postNotificationName:SDWebImageDownloadFinishNotification object:self];
            });
        }
        
        if (![[NSURLCache sharedURLCache] cachedResponseForRequest:_request]) {
            responseFromCached = NO;
        }
        
        if (completionBlock) {
            if (self.options & SDWebImageDownloaderIgnoreCachedResponse && responseFromCached) {
                completionBlock(nil, nil, nil, YES);
            } else if (self.imageData) {
                UIImage *image = [UIImage sd_imageWithData:self.imageData];
    //增加的代码
                NSData *data = UIImageJPEGRepresentation(image, 1);
                self.imageData = [NSMutableData dataWithData:data];
    //
                NSString *key = [[SDWebImageManager sharedManager] cacheKeyForURL:self.request.URL];
                image = [self scaledImageForKey:key image:image];
                
                // Do not force decoding animated GIFs
                if (!image.images) {
                    if (self.shouldDecompressImages) {
                        image = [UIImage decodedImageWithImage:image];
                    }
                }
                if (CGSizeEqualToSize(image.size, CGSizeZero)) {
                    completionBlock(nil, nil, [NSError errorWithDomain:SDWebImageErrorDomain code:0 userInfo:@{NSLocalizedDescriptionKey : @"Downloaded image has 0 pixels"}], YES);
                }
                else {
                    completionBlock(image, self.imageData, nil, YES);
                }
            } else {
                completionBlock(nil, nil, [NSError errorWithDomain:SDWebImageErrorDomain code:0 userInfo:@{NSLocalizedDescriptionKey : @"Image data is nil"}], YES);
            }
        }
        self.completionBlock = nil;
        [self done];
    }

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