ALAssetsLibraryの取り扱い方法メモ

gistfile1.m

// AssetsLibrary.frameworkを追加し、
// .hで@property (nonatomic, strong) ALAssetsLibrary *library;とか宣言しておく
// 以下は、カメラロール内のある時点以降の画像をすべてUITableViewに表示しようとしている例

-(void)initAssetsLibrary
{
    // TODO 保存時刻古い順でソートしたい → AssetsLibrary標準のAPIではできない
    static dispatch_once_t pred = 0;
    dispatch_once(&pred, ^{
        self.library = [[ALAssetsLibrary alloc] init];
    });
    NSMutableArray *collector = [[NSMutableArray alloc] initWithCapacity:0];
    NSUserDefaults *uDefault = [NSUserDefaults standardUserDefaults];
    NSDate *uploaded_date = [uDefault objectForKey:@"UPLOAD_COMPLETE_DATE"];
    NSDate *install_date = [uDefault objectForKey:@"INSTALL_DATE"];
    [self.library enumerateGroupsWithTypes:ALAssetsGroupSavedPhotos
                                usingBlock:^(ALAssetsGroup *group, BOOL *stop) {
                                    [group enumerateAssetsUsingBlock:^(ALAsset *asset, NSUInteger index, BOOL *stop) {
                                        if ([[asset valueForProperty:ALAssetPropertyType] isEqualToString:ALAssetTypePhoto]) {
                                            NSDate *date = [asset valueForProperty:ALAssetPropertyDate];
                                            NSTimeInterval since_upload = [date timeIntervalSinceDate:uploaded_date];
                                            NSTimeInterval since_install = [date timeIntervalSinceDate:install_date];
                                            if ( (since_install > 0 ) && (since_upload != since_upload || since_upload > 0) )
                                                [collector addObject:asset];
                                        }
                                    }];
                                    self.photos = collector;
                                    [self.mytableview reloadData];
                                    self.uploadNum = [NSNumber numberWithInt:[self.photos count] ];
                                    NSLog(@"upload num: %@", [self.uploadNum description]);
                                }
                              failureBlock:^(NSError *error) {
                                  NSLog(@"asset lib enumerate error");
                              }
     ];
}