PHAssetCollection 가져올 때 Type과 OS버전을 구분해서 가져오기

사진 접근 권한을 요청한 뒤에 권한이 있을 경우에만 계속 실행이 되도록 한다.

그렇지 않으면 초기 권한요청 후 데이터 없음 화면이 보여질 수 있다.

 

func fetchCollections() -> [PHAssetCollection] {
    let controller = self.navigationController as MSPhotoPickerController;
    var collections = [PHAssetCollection]()
    var album: PHFetchResult;
    var subtypes = controller.collectionSubtypes
    
    // has Any
    if contains(subtypes, PHAssetCollectionSubtype.Any) {
        var album: PHFetchResult;
        
        // for PHAssetCollectionType.SmartAlbumd
        album = PHAssetCollection.fetchAssetCollectionsWithType(PHAssetCollectionType.SmartAlbum,
            subtype: PHAssetCollectionSubtype.Any,
            options: nil)
        album.enumerateObjectsUsingBlock { (collection, index, isStop) -> Void in
            collections.append(collection as PHAssetCollection)
        }
        
        // for PHAssetCollectionType.Album
        album = PHAssetCollection.fetchAssetCollectionsWithType(PHAssetCollectionType.Album,
            subtype: PHAssetCollectionSubtype.Any,
            options: nil)
        album.enumerateObjectsUsingBlock { (collection, index, isStop) -> Void in
            collections.append(collection as PHAssetCollection)
        }
    }
    else {
        for i in 0 ..< subtypes.count {
            var type = NSNotFound;
            var subtype = subtypes[i];
            
            let osVersion = (UIDevice.currentDevice().systemVersion as NSString).floatValue
            if 8.1 > osVersion {
                switch subtype {
                case .SmartAlbumUserLibrary, .AlbumMyPhotoStream:
                    continue
                    
                default:
                    break
                }
            }
            else {
                switch subtype {
                case .SmartAlbumGeneric, .SmartAlbumRecentlyAdded:
                    continue
                    
                default:
                    break
                }
            }
            
            
            switch subtype.rawValue {
            case 0 ..< PHAssetCollectionSubtype.SmartAlbumGeneric.rawValue:
                type = PHAssetCollectionType.Album.rawValue;
                break;
                
            case PHAssetCollectionSubtype.SmartAlbumGeneric.rawValue ..< PHAssetCollectionSubtype.Any.rawValue:
                type = PHAssetCollectionType.SmartAlbum.rawValue;
                break;
                
            default:
                break;
            }
            
            if NSNotFound != type {
                let collectionType = PHAssetCollectionType(rawValue: type)!;
                let album = PHAssetCollection.fetchAssetCollectionsWithType(collectionType,
                    subtype: subtype,
                    options: nil)
                
                album.enumerateObjectsUsingBlock { (collection, index, isStop) -> Void in
                    collections.append(collection as PHAssetCollection)
                }
                
            }
        }
        
    }
    
    return collections
}