Crashed when album is empty

[heefan]

Hi bro,

Please test the following scenario which I got crashed.

1. create an empty folder in Photos(Apple App), let's call it 'test'
2. run your application

Result : Application will crash when loading photo.
Reason: Application tries to create thumbnail, but the empty folder haven't had photo yet. It means the operation is on the nil pointer.

Source : AssetHelper.m

- (NSDictionary *)getGroupInfo:(NSInteger)nIndex
{ 
    return @{@"name" : [_assetGroups[nIndex] valueForProperty:ALAssetsGroupPropertyName],
             @"count" : @([_assetGroups[nIndex] numberOfAssets]),
             @"thumbnail" : [UIImage imageWithCGImage:[(ALAssetsGroup*)_assetGroups[nIndex] posterImage]]};
}

---

My temp solution

- (NSDictionary *)getGroupInfo:(NSInteger)nIndex
{
     if ([_assetGroups[nIndex] numberOfAssets] != 0)  {
         return @{@"name" : [_assetGroups[nIndex] valueForProperty:ALAssetsGroupPropertyName],
             @"count" : @([_assetGroups[nIndex] numberOfAssets]),
             @"thumbnail" : [UIImage imageWithCGImage:[(ALAssetsGroup*)_assetGroups[nIndex] posterImage]]};
     } else {
           return @{@"name" : [_assetGroups[nIndex] valueForProperty:ALAssetsGroupPropertyName],
             @"count" : @([_assetGroups[nIndex] numberOfAssets])};
    }
}

Workflow:
Check whether the folder has photo,

1. if has, work as previous
2. if not, don't generate image for thumbnail.

Result:
UI will list the empty folder name as well.
It shows empty content if user clicks into the folder.

Plus:
And even you may not want to list the empty folder in the list, this depends on your designate UX, here I just give the report and simple solution.

Cheers

[donobono]

I could not find this crash. I don't know why. :-(
Anyway I removed thumbnail from group info, because I don't use it.

Please test with new sources and let me know the result..
Thank you for your feedback!!

[heefanlee]

I forgot to say my testing environment:
iOS7.1 Xcode5.1.1 tested on iPad device.

For my case, it crashes all the time if I created empty folder in Photos. Please refer to the attached.
As you removed the thumbnail generation, it will not crash any more. ;)

Cheers

[stonexing]

//空相册获取不到封面图片 添加封面图片即可

• (NSDictionary _)getGroupInfo:(NSInteger)nIndex
  {
  NSString *name = [_assetGroups[nIndex] valueForProperty:ALAssetsGroupPropertyName];
  int count = [assetGroups[nIndex] numberOfAssets];
  UIImage *image = [UIImage imageWithCGImage:[(ALAssetsGroup)_assetGroups[nIndex] posterImage]];
  //Empty Album sometime cannot get poster image,
  if (image == nil) {
  image = [UIImage imageNamed:@"poster.png"];
  }
  return @{@"name" : name,
  @"count" : @(count),
  @"thumbnail" : image};
  }