iOS8之后遍历相册的方法

PHFetchResult *result = [PHAssetCollection fetchAssetCollectionsWithType:PHAssetCollectionTypeAlbum subtype:PHAssetCollectionSubtypeAny options:nil];

[result enumerateObjectsUsingBlock:^(id  _Nonnull obj, NSUInteger idx, BOOL * _Nonnull stop) {
PHAssetCollection *c = (PHAssetCollection *)obj;
NSLog(@"names = %@", c.localizedTitle);

}];