从ALAssetsLibrary获取所有照片

Question

This only returns some of the albums from Photos and the albums I'm getting doesn't include the same number of assets as there are images in them in the Photos app.

NSMutableArray *groups = [[NSMutableArray alloc] init];
ALAssetsLibrary *assetLibrary = [[ALAssetsLibrary alloc] init];
[assetLibrary enumerateGroupsWithTypes:ALAssetsGroupAll
    usingBlock:^(ALAssetsGroup *group, BOOL *stop) {
      if (group) {
          [group setAssetsFilter:[ALAssetsFilter allPhotos]];
          [groups addObject:group];
      } else {
          block([groups copy], nil);
      }
    }
    failureBlock:^(NSError *error) {
      block(nil, error);
    }];

What do I need to do to get all 1000 of them?

Answer 1

something like

- (void)loadLibraryGroups
{
    if (self.assetsLibrary == nil) {
        _assetsLibrary = [[ALAssetsLibrary alloc] init];
    }
    if (self.groups == nil) {
        _groups = [[NSMutableArray alloc] init];
    } else {
        [self.groups removeAllObjects];
    }

    // setup our failure view controller in case enumerateGroupsWithTypes fails
    ALAssetsLibraryAccessFailureBlock failureBlock = ^(NSError *error) {

        NSString *errorMessage = nil;
        switch ([error code]) {
            case ALAssetsLibraryAccessUserDeniedError:
            case ALAssetsLibraryAccessGloballyDeniedError:
                errorMessage = @"The user has declined access to it.";
                break;
            default:
                errorMessage = @"Reason unknown.";
                break;
        }
    };

    // emumerate through our groups and only add groups that contain photos
    ALAssetsLibraryGroupsEnumerationResultsBlock listGroupBlock = ^(ALAssetsGroup *group, BOOL *stop) {

        ALAssetsFilter *onlyPhotosFilter = [ALAssetsFilter allPhotos];
        [group setAssetsFilter:onlyPhotosFilter];
        if ([group numberOfAssets] > 0)
        {
            NSLog(@"group ==> %@",group);
            [self.groups addObject:group];
        }
        else
        {
            NSLog(@"Empty Groups load all items");

            for (ALAssetsGroup *group in self.groups) {
                [self loadImageForEachGroup:group];
            }

        }
    };

    // enumerate only photos
    NSUInteger groupTypes = ALAssetsGroupAlbum | ALAssetsGroupEvent | ALAssetsGroupFaces | ALAssetsGroupSavedPhotos;
    [self.assetsLibrary enumerateGroupsWithTypes:groupTypes usingBlock:listGroupBlock failureBlock:failureBlock];

    NSLog(@"finish load groups");
}

- (void)loadImageForEachGroup:(ALAssetsGroup *)group
{
    if (!self.assets) {
        _assets = [[NSMutableArray alloc] init];
    } else {
        [self.assets removeAllObjects];
    }

    ALAssetsGroupEnumerationResultsBlock assetsEnumerationBlock = ^(ALAsset *result, NSUInteger index, BOOL *stop) {
        if (result != nil) {
            [self.assets addObject:result];
        } else {
            [self.collectionView reloadData];
        }
    };

    ALAssetsFilter *onlyPhotosFilter = [ALAssetsFilter allPhotos];
    [group setAssetsFilter:onlyPhotosFilter];
    [group enumerateAssetsUsingBlock:assetsEnumerationBlock];
}

And Load in collection

- (NSInteger)collectionView:(UICollectionView *)collectionView numberOfItemsInSection:(NSInteger)section
{
    return self.assets.count;
}

- (UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath
{
    static NSString *CellIdentifier = @"photoCell";

    UICollectionViewCell *cell = [collectionView dequeueReusableCellWithReuseIdentifier:CellIdentifier forIndexPath:indexPath];
    // Configure the cell

    // load the asset for this cell
    ALAsset *asset = self.assets[indexPath.row];
    CGImageRef thumbnailImageRef = [asset thumbnail];
    UIImage *thumbnail = [UIImage imageWithCGImage:thumbnailImageRef];

    // apply the image to the cell
    UIImageView *imageView = (UIImageView *)[cell viewWithTag:1];
    imageView.image = thumbnail;

    return cell;
}