PhotoKit: fetchAssetCollectionsWithLocalIdentifiers失败

Question

下面的代码通过3个简单的步骤突出显示了这个问题：

1)获取moments

2)缓存时刻localIdentifier

3)获取带有标识符的时刻:失败(在设备上，iOS 8.2 )

- ( void )momentLocalIdTest
{
    PHFetchResult       * fetchResult;
    PHAssetCollection   * moment;
    NSString            * localIdentifier;

    fetchResult = [ PHAssetCollection fetchMomentsWithOptions: nil ];

    if( fetchResult.count == 0 )
        return;

    moment          = fetchResult.firstObject;
    localIdentifier = moment.localIdentifier;
    fetchResult     = [ PHAssetCollection fetchAssetCollectionsWithLocalIdentifiers: @[ localIdentifier ] options: nil ];

    if( fetchResult.count == 0 )
        NSLog( @"AssetCollection with localIdentifier %@ not found!!!", localIdentifier );
}

我是不是误解了什么？这看起来很简单。

感谢任何人的帮助！

Answer 1

我也遇到了同样的问题，不知道这段代码出了什么问题。我认为这个API就是简单的破解(至少8.0到8.4 )

下面是一个变通方法代码；您基本上必须从标识符重新生成PHAssetCollection实例

PHFetchOptions *options = [PHFetchOptions new];
options.predicate = [NSPredicate predicateWithFormat:@"localIdentifier = %@", identifier];

PHAssetCollection *collection = [[PHAssetCollection fetchMomentsWithOptions:options] firstObject];
PHFetchResult *results = [PHAsset fetchAssetsInAssetCollection:collection options:nil];