解决加载大量图片时的崩溃问题

原文链接

bug SDWebImage

1.UIImage+MultiFormat这个类里面添加如下压缩方法

+(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;
}

2.修改sd_imageWithData方法：选择性的压缩image

  image = [[UIImage alloc] initWithData:data];
        if (data.length/1024 > 128) {
            image = [self compressImageWith:image];
        }

3.在SDWebImageDownloaderOperation中方法添加两行代码

UIImage *image = [UIImage sd_imageWithData:self.imageData];
//将等比压缩过的image在赋在转成data赋给self.imageData
NSData *data = UIImageJPEGRepresentation(image, 1);
self.imageData = [NSMutableData dataWithData:data];

4.在sd_setImageWithURL方法后调用

[[SDImageCache sharedImageCache] setValue:nil forKey:@"memCache"];