My Photo Stream (我的照片流)ALAsset return nil

做了一个图片多选的功能,因为要支持iOS6,所以使用了AssetsLibrary遍历读取照片,但是选取我的照片流相册中的照片时,通过NSUrl,即图片的地址读取该照片ALAsset 为nil.
看了一下百度云将我的照片流过滤掉了,360云盘也出现了选取图片为nil 的情况.

google了一下, 以下为解决方法,如果返回为nil的话,需要再重新遍历一次group,将其取出:

 
 
 
  
 
(void)loadItem:(NSURL *)url withSuccessBlock:(ALAssetsLibraryAssetForURLResultBlock)resultBlock andFailureBlock:(ALAssetsLibraryAccessFailureBlock)failureBlock {
 ALAssetsLibrary *assetslibrary = [[ALAssetsLibrary alloc] init];
 
[assetslibrary assetForURL:url
 resultBlock:^(ALAsset *asset)
 {
 if (asset){
 //////////////////////////////////////////////////////
 // SUCCESS POINT #1 - asset is what we are looking for
 //////////////////////////////////////////////////////
 resultBlock(asset);
 }
 else {
 // On iOS 8.1 [library assetForUrl] Photo Streams always returns nil. Try to obtain it in an alternative way
 
       [assetslibrary enumerateGroupsWithTypes:ALAssetsGroupPhotoStream
                                    usingBlock:^(ALAssetsGroup *group, BOOL *stop)
        {
            [group enumerateAssetsWithOptions:NSEnumerationReverse usingBlock:^(ALAsset *result, NSUInteger index, BOOL *stop) {
                if([result.defaultRepresentation.url isEqual:url])
                {
                    ///////////////////////////////////////////////////////
                    // SUCCESS POINT #2 - result is what we are looking for
                    ///////////////////////////////////////////////////////
                    resultBlock(result);
                    *stop = YES;
                }
            }];
        }
           failureBlock:^(NSError *error)
        {
            NSLog(@"Error: Cannot load asset from photo stream - %@", [error localizedDescription]);
            failureBlock(error);
            
        }];
   }
 
}
 failureBlock:^(NSError *error)
 {
 NSLog(@"Error: Cannot load asset - %@", [error localizedDescription]);
 failureBlock(error);
 }
 ];
 }