ALAsset

来源：互联网发布：淘宝买xbox哪一家好编辑：程序博客网时间：2024/05/21 06:58
1、ALAsset,ALAssetsLibrary,ALAssetsgroup常见属性及用法
http://blog.csdn.net/shenjx1225/article/details/9293269
2、ALAssetsGroup详解
ALAssetsGroup类是系统用于映射相册资源中的每个相册，可以通过该类获取相册中的资源文件，并且能向相册中添加资源文件
//保存图片到系统默认的相册中，使用cgimageref的形式，并且选择图片以什么旋转方向的形式保存，并返回照片的url地址/* typedef enum { ALAssetOrientationUp,            // default orientation ALAssetOrientationDown,          // 180 deg rotation ALAssetOrientationLeft,          // 90 deg CCW ALAssetOrientationRight,         // 90 deg CW ALAssetOrientationUpMirrored,    // as above but image mirrored along other axis. horizontal flip ALAssetOrientationDownMirrored,  // horizontal flip ALAssetOrientationLeftMirrored,  // vertical flip ALAssetOrientationRightMirrored, // vertical flip } ALAssetOrientation; */UIImage* image = [UIImage imageNamed:@"test.png"];[_library writeImageToSavedPhotosAlbum:[image CGImage] orientation:ALAssetOrientationLeft completionBlock:^(NSURL *assetURL, NSError *error) {    NSLog(@"save image:%@",assetURL);    //通过ALAssetsLibrary迭代取出所有相册    [_library enumerateGroupsWithTypes:ALAssetsGroupAll usingBlock:^(ALAssetsGroup *group, BOOL *stop) {        NSString* groupname = [group valueForProperty:ALAssetsGroupPropertyName];        //如果相册的名称是test的时候，对其进行操作        if ([groupname isEqualToString:@"test"]) {            //设置相册组的筛选条件，ALAssetsFilter类表示筛选条件，allPhotos代表相册只包含相片，allVideos代表只包含视频，allAssets代表包含所有资源            [group setAssetsFilter:[ALAssetsFilter allPhotos]];            //通过刚保存的照片的url，把保存到默认相册的照片也保存到test相册中            [_library assetForURL:assetURL resultBlock:^(ALAsset *asset) {                //添加资源到指定的相册                [group addAsset:asset];                //获取相册中一共的资源数量                int count = [group numberOfAssets];                NSLog(@"count:%d",count);                dispatch_queue_t main = dispatch_get_main_queue();                dispatch_async(main, ^{                    //获取相册的封面图片                    CGImageRef poster = [group posterImage];                    [imageView setImage:[UIImage imageWithCGImage:poster]];                });                //NSString *const ALAssetsGroupPropertyName;                //NSString *const ALAssetsGroupPropertyType;                //NSString *const ALAssetsGroupPropertyPersistentID;                //NSString *const ALAssetsGroupPropertyURL;                //查看相册的名字                NSLog(@"ALAssetsGroupPropertyName:%@",[group valueForProperty:ALAssetsGroupPropertyName]);                //查看相册的类型                NSLog(@"ALAssetsGroupPropertyType:%@",[group valueForProperty:ALAssetsGroupPropertyType]);                //查看相册的存储id                NSLog(@"ALAssetsGroupPropertyPersistentID:%@",[group valueForProperty:ALAssetsGroupPropertyPersistentID]);                //查看相册存储的位置地址                NSLog(@"ALAssetsGroupPropertyURL:%@",[group valueForProperty:ALAssetsGroupPropertyURL]);                //按遍历顺序获取指定索引的资源，遍历顺序可以是先序或倒序                /*                 enum {                 NSEnumerationConcurrent = (1UL << 0),                 NSEnumerationReverse = (1UL << 1),                 };                 typedef NSUInteger NSEnumerationOptions;                 */                [group enumerateAssetsAtIndexes:[NSIndexSet indexSetWithIndex:0] options:NSEnumerationConcurrent usingBlock:^(ALAsset *result, NSUInteger index, BOOL *stop) {                                    }];                //按顺便遍历获取相册中所有的资源，index代表资源的索引，stop赋值为false时，会停止遍历                [group enumerateAssetsUsingBlock:^(ALAsset *result, NSUInteger index, BOOL *stop) {                                    }];                //按顺便遍历获取相册中所有的资源，遍历顺序可以是先序或倒序，index代表资源的索引，stop赋值为false时，会停止遍历                [group enumerateAssetsWithOptions:NSEnumerationReverse usingBlock:^(ALAsset *result, NSUInteger index, BOOL *stop) {                                    }];                            } failureBlock:^(NSError *error) {                            }];        }    } failureBlock:^(NSError *error) {            }];}];
0 0