获取 GDataFeedPhotoAlbum 返回错误的对象类型

Question

我正在尝试在 iphone 上获取 picasa 网络相册，已从 google.code 下载了代码和示例，但遇到了一个问题，即获取相册提要返回给我的提要对象类型错误 - GDataEntryBase 而不是 GDataEntryPhoto。

这是我正在使用的代码：

首先我调用它来获取我所有的专辑：

- (void)fetchAllAlbums 
{
    NSLog(@"Fetching all albums");

    //request albums
    GDataServiceTicket *ticket;    
    NSURL *feedURL = [GDataServiceGooglePhotos photoFeedURLForUserID:myemail
                                                             albumID:nil
                                                           albumName:nil
                                                             photoID:nil
                                                                kind:nil
                                                              access:nil];
    ticket = [_GooglePhotoService fetchFeedWithURL:feedURL
                                          delegate:self
                                 didFinishSelector:@selector(albumListFetchTicket:finishedWithFeed:error:)];
    [self set_AlbumFetchTicket: ticket];
}

现在，我在回调中调用以获取每个返回相册的所有照片：

- (void)albumListFetchTicket:(GDataServiceTicket *)ticket
            finishedWithFeed:(GDataFeedPhotoUser *)feed
                       error:(NSError *)error 
{
    [self set_UserAlbumFeed: feed];
    [self set_AlbumFetchError:error];
    [self set_AlbumFetchTicket:nil];

    if (error == nil) {
        NSLog(@"Got albums!");

        for (GDataEntryPhotoAlbum * albumEntry in _UserAlbumFeed)
        {
            NSLog(@"Album Title: %@", [[albumEntry title] stringValue]);
            {
                NSLog(@"Fetching photos!");

                [self set_AlbumPhotosFeed:nil];
                [self set_PhotosFetchError:nil];
                [self set_PhotosFetchTicket:nil];

                GDataServiceTicket *ticket;
                ticket = [_GooglePhotoService fetchFeedWithURL: [[albumEntry feedLink] URL]
                                                      delegate: self
                                             didFinishSelector: @selector(photosTicket:finishedWithFeed:error:)];

                [self set_PhotosFetchTicket:ticket];

            }
        }
    }
}

这是每个相册照片提要获取的回调：

// photo list fetch callback
- (void)photosTicket:(GDataServiceTicket *)ticket
    finishedWithFeed:(GDataFeedPhotoAlbum *)feed
               error:(NSError *)error 
{
    //tell me what class you are
    NSLog(@"Feed class: %@", NSStringFromClass([feed class]));

    [self set_AlbumPhotosFeed:   feed];
    [self set_PhotosFetchError:  error];
    [self set_PhotosFetchTicket: ticket];

    if (error == nil)
    {
        NSLog(@"Got Photos!");

        for (GDataEntryPhoto * photo in feed)
        {
            NSLog(@"Title: %@", [[photo title] stringValue]);

            //tell me what class you are
            NSLog(@"%@", NSStringFromClass([photo class]));

            //NSArray * thumbnails = [[photo mediaGroup] mediaThumbnails];
            //NSLog(@"thumbnails count: %d", [thumbnails count]);
            //NSLog(@"Photo thumnail url: %@", [[thumbnails objectAtIndex:0] URLString]);
        }            
    }
}

问题在于最后一个回调中的提要中的条目不是 GDataEntryPhoto 类型，只是基本 GDataEntryBase - 因此尝试访问它们的缩略图 url 会使应用程序崩溃。 该代码是从 google 的 cocoa (non-touch) 示例中复制而来的，并且可以正常工作 - 返回的提要填充了 GDateEntryPhoto 对象。

任何帮助将不胜感激。

Answer 1

将-ObjC -all_load 添加到您的xcodeproject 中的Other Linker Flags，然后将SystemConfiguration.framework、CFNetwork.framework 和Security.framework 添加到Build Phases -> 使用二进制文件链接库。