解决iOS8下ALAssetsLibrary创建相册的bug

说到ALAssetsLibrary，相信搞iOS开发的大都知道它，在iOS上做过相册相关功能的应该对这个都比较熟悉了，用它来操作访问相册是很方便的。但是，，，，自从iOS8发布后，ALAssetsLibrary在Stack Overflow上被各种讨论了。因为在iOS8上用这个库创建相册会有个bug：创建相册，手动删除它，再用这个库去创建刚被删除的相册，这个时候方法回调是不会跑fail模块的，它走的是正常流程，但是带回来的group却是nil。

-(void)saveImageToXYAlbum:(UIImage*)image completion:(SaveImageCompletion)completion
{
if(image){
__weak ALAssetsLibrary *weakAssetsLibrary = assetsLibrary;
__weak XYWallPaperHelper *weakSelf = self;
dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{

if(TT_IS_IOS8_AND_UP){
PHPhotoLibrary* photoLibrary = [PHPhotoLibrary sharedPhotoLibrary];
[photoLibrary performChanges:^{
PHFetchResult* fetchCollectionResult;
PHAssetCollectionChangeRequest* collectionRequest;
NSString *albumIdentifier = [weakSelf xyWallPaperAlbumIdentifier];
if(albumIdentifier){
fetchCollectionResult = [PHAssetCollection fetchAssetCollectionsWithLocalIdentifiers:@[albumIdentifier] options:nil];
PHAssetCollection* exisitingCollection = fetchCollectionResult.firstObject;
collectionRequest = [PHAssetCollectionChangeRequest changeRequestForAssetCollection:exisitingCollection];
}else{
fetchCollectionResult = [PHAssetCollection fetchAssetCollectionsWithLocalIdentifiers:@[XYWallPaperAlbum] options:nil];
// Create a new album
if ( !fetchCollectionResult || fetchCollectionResult.count==0 ){
collectionRequest = [PHAssetCollectionChangeRequest creationRequestForAssetCollectionWithTitle:XYWallPaperAlbum];
[weakSelf saveXYWallPaperAblumIdentifier:collectionRequest.placeholderForCreatedAssetCollection.localIdentifier];
}
}
PHAssetChangeRequest* createAssetRequest = [PHAssetChangeRequest creationRequestForAssetFromImage:image];
[collectionRequest addAssets:@[createAssetRequest.placeholderForCreatedAsset]];

} completionHandler:^(BOOL success, NSError *error){
completion(error);
}];
}else{
[weakAssetsLibrary saveImage:image toAlbum:XYWallPaperAlbum withCompletionBlock:completion];
}
});
}
}

View Code

这里有个地方需要注意，创建相册后要存储一下localIdentifier，因为下次再获取AssetCollection的时候需要用到它。如果每次都用相册名去试图获取到之前创建的同名AssetCollection，不会得到结果的。就这里需要注意一下，其他倒没什么，代码也比较简单。 上面代码部分针对iOS8以下版本的代码逻辑，这里就不赘述了，网上一大把。

转载自：http://blog.csdn.net/jerrychenly/article/details/44858355