ios - 无法使用 PHPhotoLibrary 将 UIImage 保存到相机胶卷

Question

我正在尝试将 UIImage 保存到相机胶卷。Apple 弃用了 UIImageWriteToSavedPhotosAlbum，因此我避免使用它(ALAssets 也是如此)，它会强制使用 PhotoLibrary。

这是我正在使用的代码:

定义:

var rollCollection : PHAssetCollection!;

初始化:

let result = PHAssetCollection.fetchAssetCollectionsWithType(.SmartAlbum, subtype: .SmartAlbumUserLibrary, options: nil);
rollCollection = result.firstObject as? PHAssetCollection;

图片保存代码:

    if (rollCollection != nil){
        PHPhotoLibrary.sharedPhotoLibrary().performChanges({
            let assetRequest = PHAssetChangeRequest.creationRequestForAssetFromImage(
                self.originalImg!);

            let albumChangeRequest = PHAssetCollectionChangeRequest(forAssetCollection: self.rollCollection!);
            let assetPlaceHolder = assetRequest.placeholderForCreatedAsset;
            albumChangeRequest!.addAssets([assetPlaceHolder!])

            }, completionHandler: { success, error in
                dispatch_async(dispatch_get_main_queue(), {
                    print ("\(error!)");
                    if (!success){
                        self.presentViewController(self.alertCantSave!, animated: false, completion: nil);
                    }
                    else {
                        self.presentViewController(self.alertSaved!, animated: false, completion: nil);
                    }
                });

        })
    }
    else {
        dispatch_async(dispatch_get_main_queue(), {
        self.presentViewController(self.alertCantSave!, animated: false, completion: nil);
        });
    }

每次我尝试保存图像时，我都会收到以下错误:

Error Domain=NSCocoaErrorDomain Code=-1 "(null)"

有什么想法吗？我找不到任何解释，到处寻找，我发现了一个类似于我的代码片段(包括 Apple 的文档:https://developer.apple.com/library/ios/documentation/Photos/Reference/PHPhotoLibrary_Class/)

谢谢。

Answer 1

我在寻找完全相同的东西几个小时后才发现这个问题。

经过一番尝试，我得出了一个对我有用的答案，所以我在这里分享它，以防其他人在未来寻找类似的东西。

// Make sure the image is not nil
guard let image = image else {
  // No image here...
  return
}

// Perform changes to the library 
PHPhotoLibrary.sharedPhotoLibrary().performChanges({
  // You only need to create the request, there is no need to define the placeholder 
  // nor to add the asset because swift does not like it when you try to modify the camera roll.
  PHAssetChangeRequest.creationRequestForAssetFromImage(image)

}, completionHandler: { success, error in
  // Same as what you have...

})

如果您想了解如何将图像保存到自定义相册以及从自定义相册中查询图像的示例，请查看此答案。 Save images with PHImageManager