像安卓一样在相册里创建自己的文件夹 － Saving photos in custom photo

不知道又没有更好的方式方法，目前觉得这个方案还挺不错的。

#import "ALAssetsLibrary+CustomPhotoAlbum.h"

@implementation ALAssetsLibrary(CustomPhotoAlbum)

-(void)saveImage:(UIImage*)image toAlbum:(NSString*)albumName withCompletionBlock:(SaveImageCompletion)completionBlock
{
    //write the image data to the assets library (camera roll)
    [self writeImageToSavedPhotosAlbum:image.CGImage orientation:(ALAssetOrientation)image.imageOrientation 
                        completionBlock:^(NSURL* assetURL, NSError* error) {
                              
                          //error handling
                          if (error!=nil) {
                              completionBlock(error);
                              return;
                          }

                          //add the asset to the custom photo album
                          [self addAssetURL: assetURL 
                                    toAlbum:albumName 
                        withCompletionBlock:completionBlock];
                          
                      }];
}

-(void)addAssetURL:(NSURL*)assetURL toAlbum:(NSString*)albumName withCompletionBlock:(SaveImageCompletion)completionBlock
{
    __block BOOL albumWasFound = NO;
    
    //search all photo albums in the library
    [self enumerateGroupsWithTypes:ALAssetsGroupAlbum 
                        usingBlock:^(ALAssetsGroup *group, BOOL *stop) {

                            //compare the names of the albums
                            if ([albumName compare: [group valueForProperty:ALAssetsGroupPropertyName]]==NSOrderedSame) {
                                
                                //target album is found
                                albumWasFound = YES;
                                
                                //get a hold of the photo's asset instance
                                [self assetForURL: assetURL 
                                      resultBlock:^(ALAsset *asset) {
                                                  
                                          //add photo to the target album
                                          [group addAsset: asset];
                                          
                                          //run the completion block
                                          completionBlock(nil);
                                          
                                      } failureBlock: completionBlock];

                                //album was found, bail out of the method
                                return;
                            }
                            
                            if (group==nil && albumWasFound==NO) {
                                //photo albums are over, target album does not exist, thus create it
                                
                                __weak ALAssetsLibrary* weakSelf = self;

                                //create new assets album
                                [self addAssetsGroupAlbumWithName:albumName 
                                                      resultBlock:^(ALAssetsGroup *group) {
                                                                  
                                                          //get the photo's instance
                                                          [weakSelf assetForURL: assetURL 
                                                                        resultBlock:^(ALAsset *asset) {

                                                                            //add photo to the newly created album
                                                                            [group addAsset: asset];
                                                                            
                                                                            //call the completion block
                                                                            completionBlock(nil);

                                                                        } failureBlock: completionBlock];
                                                          
                                                      } failureBlock: completionBlock];

                                //should be the last iteration anyway, but just in case
                                return;
                            }
                            
                        } failureBlock: completionBlock];
    
}

@end

2. 在相应的controller里

#import <AssetsLibrary/AssetsLibrary.h> @property (strong, atomic) ALAssetsLibrary* library; - (void)viewDidLoad { [super viewDidLoad]; self.library = [[ALAssetsLibrary alloc] init]; } - (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingImage:(UIImage *)image editingInfo:(NSDictionary *)editingInfo { [self.library saveImage:image toAlbum:@"Touch Code Magazine" withCompletionBlock:^(NSError *error) { if (error!=nil) { NSLog(@"Big error: %@", [error description]); } }]; [picker dismissModalViewControllerAnimated:NO]; } 3. 以上代码是别人的劳动成果，在这里希望能够抛砖引玉，找到更多更好的解决方案。

原博客附有demo， 可自行参考 http://www.touch-code-magazine.com/ios5-saving-photos-in-custom-photo-album-category-for-download/