ios - setImageWithURLRequest :placeholderImage:success:failure No block is called

Question

我正在尝试使用 AFNetworking 2.0 从 url 异步获取图像

我的问题是既没有调用成功也没有调用失败

我已经在浏览器中检查了我的 URL，所以问题不在这里

UIImageView *imgv = [[UIImageView alloc] init];
[imgv setImageWithURLRequest:myURL
            placeholderImage:nil
                     success:^(NSURLRequest *request, NSHTTPURLResponse *response, UIImage *image) {
                                        /*some code*/
                     failure:^(NSURLRequest *request, NSHTTPURLResponse *response, NSError *error) {
                                        /*some code*/       
];

当我深入了解 setImageWithUrlRequest:placeholderImage:success:failure

   __weak __typeof(self)weakSelf = self;
    self.af_imageRequestOperation = [[AFHTTPRequestOperation alloc] initWithRequest:urlRequest];
    self.af_imageRequestOperation.responseSerializer = self.imageResponseSerializer;
    [self.af_imageRequestOperation setCompletionBlockWithSuccess:^(AFHTTPRequestOperation *operation, id responseObject) {
        __strong __typeof(weakSelf)strongSelf = weakSelf;
        if ([[urlRequest URL] isEqual:[strongSelf.af_imageRequestOperation.request URL]]) {
            if (success) {
                success(urlRequest, operation.response, responseObject);
            } else if (responseObject) {
                strongSelf.image = responseObject;
            }

            if (operation == strongSelf.af_imageRequestOperation){
                    strongSelf.af_imageRequestOperation = nil;
            }
        }

        [[[strongSelf class] sharedImageCache] cacheImage:responseObject forRequest:urlRequest];
    } failure:^(AFHTTPRequestOperation *operation, NSError *error) {
        __strong __typeof(weakSelf)strongSelf = weakSelf;
        if ([[urlRequest URL] isEqual:[strongSelf.af_imageRequestOperation.request URL]]) {
            if (failure) {
                failure(urlRequest, operation.response, error);
            }

            if (operation == strongSelf.af_imageRequestOperation){
                    strongSelf.af_imageRequestOperation = nil;
            }
        }
    }];

我的代码得到了 [self.af_imageRequestOperation setCompletionBlockWithSuccess:^( AFHTTPRequestOperation *operation, id responseObject) {
成功，但我注意到 __strong __typeof(weakSelf)strongSelf = weakSelf; 都是 nil

有什么想法吗？

Answer 1

你的 imgv 永远不会被保留，所以它会在当前范围之后被释放，所以在你的 block 中 weakSelf 会在图像成功下载时被释放，这就是你得到 nil 的原因。