ALAssetsLibrary - objcmemo @ ウィキ

// 選択したファイル名を取得する
+ (NSString*)getImageFileName:(UIImagePickerController*)picker pickingMediaInfo:(NSDictionary *)info
{
    __block NSString* ret = nil;
    dispatch_semaphore_t semaphore = dispatch_semaphore_create(0);
    dispatch_queue_t queue = dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0);
    dispatch_async(queue, ^{
        if (picker.sourceType == UIImagePickerControllerSourceTypePhotoLibrary) {
            NSURL *imageURL = [info valueForKey:UIImagePickerControllerReferenceURL];
            ALAssetsLibraryAssetForURLResultBlock resultblock = ^(ALAsset *myasset)
            {
                ALAssetRepresentation *representation = [myasset defaultRepresentation];
                ret = [representation filename];
                dispatch_semaphore_signal(semaphore);
            };
            
            ALAssetsLibrary* assetslibrary = [[ALAssetsLibrary alloc] init];
            [assetslibrary assetForURL:imageURL
                           resultBlock:resultblock
                          failureBlock:nil];
        }
    });
    dispatch_semaphore_wait(semaphore, DISPATCH_TIME_FOREVER);
    return ret;
}






/*
*  写真アルバムアクセス状況を取得する
*/

// AssetsLibrary.frameworkを組み込む

NSString *message = nil;
if (![UIImagePickerController isSourceTypeAvailable:UIImagePickerControllerSourceTypeCamera]) {
    message = @"カメラを利用できません。";
}

ALAuthorizationStatus status = [ALAssetsLibrary authorizationStatus];
switch (status) {
    case ALAuthorizationStatusNotDetermined:
        message = @"まだ許可ダイアログ出たことない";
        break;
    case ALAuthorizationStatusRestricted:
        message =  @"機能制限(ペアレンタルコントロール)で許可されてない";
        break;
    case ALAuthorizationStatusDenied:
        message = @"許可ダイアログで\"いいえ\"が押されています\n"
        "設定アプリ -> プライバシー > 写真 -> 該当アプリを\"オン\"する必要があります";
        break;
    case ALAuthorizationStatusAuthorized:
        message = @"写真へのアクセスが許可されています";
        break;
    default:
        break;
}

if (message.length) {
    [[[UIAlertView alloc] initWithTitle:@"確認"
                                message:message
                               delegate:nil
                      cancelButtonTitle:@"OK"
                      otherButtonTitles: nil] show];
}