强制保存的图像与 iCloud 照片流同步

Question

我有一个定期拍摄图像的应用程序，我希望在拍摄图像后立即将它们上传到 iCloud 照片流。

似乎需要满足某些条件才能使其起作用。它似乎只在运行 iOS 8 时工作，设备连接到无线，并且通过使用 UIImagePickerController 来拍照（而不是 AVCapture）至少一次。似乎 UIImagePickerController 在出现时会改变一些系统设置，从而允许随后将图像自动上传到 iCloud 照片流。如果我只使用 AVCapture 来拍照，它将无法正常工作。我已确认在 iCloud 设置中启用了“上传到我的照片流”，并且存在活动的无线连接。

这是用于保存从 UIImagePickerController 获取的图像的方法：

- (void)saveImage : (UIImage *)image {
    // Add image to the photo library
    [[PHPhotoLibrary sharedPhotoLibrary] performChanges:^{
        PHAssetChangeRequest *assetChangeRequest =
        [PHAssetChangeRequest creationRequestForAssetFromImage:image];
    } completionHandler:^(BOOL success, NSError *error) {
        if (!success)
            NSLog(@"Error creating asset: %@", error);
    }];
}

在装有 iOS 8 的 iPad 上运行时，以下是我在设备系统日志中看到的条目：

Oct 22 21:11:06 iPad mstreamd[14409] <Notice>: (Note ) PS: MSPublisher - xxxxxxxx Submitting 1 asset collections for publication.
Oct 22 21:11:06 iPad mstreamd[14409] <Notice>: (Note ) PS: MSPublisher - xxxxxxxx Sending metadata...
Oct 22 21:11:10 iPad mstreamd[14409] <Notice>: (Note ) PS: MSPublisher - xxxxxxxx uploading 1 assets...
Oct 22 21:11:11 iPad mstreamd[14409] <Notice>: (Note ) PS: Received push notification for invitations topic: com.apple.mediastream.subscription.push userInfo: {
        r = xxxxxxxx;
    }
Oct 22 21:11:11 iPad mstreamd[14409] <Notice>: (Note ) PS: <MSIOSMediaStreamDaemon: 0x1662ad80>: Push notification received for My Photo Stream with targetPersonID xxxxxxxx.
Oct 22 21:11:12 iPad mstreamd[14409] <Notice>: (Note ) mstreamd: <MSPowerBudget: 0x1666fae0>: Plugged in to external power. Allowing file transfers.
Oct 22 21:11:12 iPad mstreamd[14409] <Notice>: (Note ) mstreamd: <MSPowerBudget: 0x1666fae0>: Push received. Allowing file transfers to continue for 60.00 seconds
Oct 22 21:11:12 iPad mstreamd[14409] <Notice>: (Note ) PS: MSPublisher - xxxxxxxx Sending metadata...
Oct 22 21:11:12 iPad mstreamd[14409] <Notice>: (Note ) PS: MSSubscriber - xxxxxxxx Found 1 new asset collections.
Oct 22 21:11:13 iPad assetsd[11536] <Warning>: Unable to open file to save extended attributes (No such file or directory).

在装有 iOS 9.1 的 iPhone 上运行时，我有类似的日志条目，除了我有关于缓存服务器的其他警告/错误消息以粗体显示：

Oct 25 22:35:28 iPhone mstreamd[1735] <Notice>: (Note ) PS: MSPublisher - xxxxxxxx Submitting 1 asset collections for publication.
Oct 25 22:35:28 iPhone mstreamd[1735] <Notice>: (Note ) PS: MSPublisher - xxxxxxxx Sending metadata...
**Oct 25 22:35:28 iPhone AssetCacheLocatorService[1658] <Warning>: #df99fdd0 [I:AssetCacheLocatorService.queue] found no caching servers**
Oct 25 22:35:28 iPhone mstreamd[1735] <Notice>: (Note ) PS: MSPublisher - xxxxxxxx uploading 1 assets...
**Oct 25 22:35:28 iPhone mstreamd[1735] <Notice>: (Error) mmcs: __mmcs_proxy_locator_exists_block_invoke:167 might have caching server returned with error: Error Domain=NSPOSIXErrorDomain Code=60 "Operation timed out" UserInfo={com.apple.AssetCacheLocator.tag=#1963bd2d, NSLocalizedDescription=quick miss requested}**
**Oct 25 22:35:29 iPhone mstreamd[1735] <Notice>: (Note ) PS: MSPublisher - xxxxxxxx Sending metadata...**
Oct 25 22:35:29 iPhone mstreamd[1735] <Notice>: (Note ) PS: Received push notification for invitations topic: com.apple.mediastream.subscription.push userInfo: {
        r = xxxxxxxx;
    }
Oct 25 22:35:29 iPhone mstreamd[1735] <Notice>: (Note ) PS: <MSIOSMediaStreamDaemon: 0x157e0c530>: Push notification received for My Photo Stream with targetPersonID xxxxxxxx.
Oct 25 22:35:29 iPhone mstreamd[1735] <Notice>: (Note ) mstreamd: <MSPowerBudget: 0x157e84410>: Plugged in to external power. Allowing file transfers.
Oct 25 22:35:29 iPhone mstreamd[1735] <Notice>: (Note ) mstreamd: <MSPowerBudget: 0x157e84410>: Push received. Allowing file transfers to continue for 60.00 seconds
Oct 25 22:35:29 iPhone mstreamd[1735] <Notice>: (Note ) PS: MSSubscriber - xxxxxxxx Found 1 new asset collections.
Oct 25 22:35:30 iPhone assetsd[1624] <Warning>: Unable to open file to save extended attributes (No such file or directory).

在 iOS 9 的这种情况下，当我的应用程序处于活动状态时，图像不会上传，只有在应用程序进入后台时才会上传。

我怀疑问题是由于 1. 某些系统设置仅在 iOS8 中通过 UIImagePickerController 的呈现激活或 2. 日志条目所建议的 iOS 9 中缓存服务器的一些问题。

有人知道发生了什么吗？任何想法将不胜感激！谢谢！

Answer 1

我想我找到了解决办法。似乎如果 AVCaptureSession 正在运行，iCloud 照片流将不会同步。调用 stopRunning 方法（如下）似乎可以解决问题：

[self.cameraSession stopRunning];