下载的数据总是为零

Question

FBFriendPickerViewController *friendPicker = [[FBFriendPickerViewController alloc] init];
friendPicker.fieldsForRequest = [[NSSet alloc] initWithObjects:@"picture", nil];
[friendPicker loadData];
[friendPicker presentModallyFromViewController:self
                                      animated:YES
                                       handler:^(FBViewController *sender, BOOL donePressed) {
                                           if (donePressed) {
NSURL *profilePictureURL = [NSURL URLWithString:friend[@"picture"][@"data"][@"url"]];
                                                               NSURLRequest *profilePictureURLRequest = [NSURLRequest requestWithURL:profilePictureURL cachePolicy:NSURLRequestUseProtocolCachePolicy timeoutInterval:10.0f]; // 
NSLog(profilePictureURL.absoluteString);
                                                               [NSURLConnection sendAsynchronousRequest:profilePictureURLRequest
                                                                                                  queue:[NSOperationQueue mainQueue]
                                                                                      completionHandler:^(NSURLResponse* response, NSData* receivedData, NSError* error)
                                                                {
                                                                    UIimage *userpic = [UIImage imageWithData:receivedData];
                                                                }];

网址不是空的： https://fbcdn-profile-a.akamaihd.net/hprofile-ak-ash4/370130_506171594_768019817_q.jpg

但receivedData是零 - 我尝试了不同的方法从网址下载数据。

有谁可以说这段代码有什么问题？这些代码正在运行，但是不久前开始返回nil数据。