Exposing an app's ubiquitous container to iCloud Drive in iOS 8

问题

I'm developing an iCloud-enabled app where users will be able to import and export files via iCloud Drive. When browsing iCloud Drive, either using the UIDocumentPickerViewController (iOS 8) or the Finder (OS X Yosemite), I can see directories created/owned by other iCloud-Drive-enabled apps, such as, Automator, Keynote, or TextEdit.

I want our app to expose its ubiquitous documents directory in iCloud Drive, too, but haven't been able to figure it out yet. Within some of the aforementioned apps' Info.plist files, I've discovered this key:

<key>NSUbiquitousContainers</key>
<dict>
    <key>com.apple.TextEdit</key>
    <dict>
        <key>NSUbiquitousContainerIsDocumentScopePublic</key>
        <true/>
        <key>NSUbiquitousContainerSupportedFolderLevels</key>
        <string>Any</string>
    </dict>
</dict>

These keys are also documented here, but I haven't found any other documentation on the broader subject. Edit/Note: Although it does not contain the answer to my questions, the Document Picker Programming Guide is a helpful resource.

I've tried adding the above-mentioned keys/values to our app but didn't see any effect. Things I've noticed/tried:

For 3rd party apps, iCloud containers are constructed this way: iCloud.$(CFBundleIdentifier). I'm not sure why TextEdit only uses the pure bundle identifier, but for our identifier, I've tried both approaches, i.e., with and without the iCloud. prefix. I've also recognised that you need to hard-code the bundle identifier (i.e., don't use iCloud.$(CFBundleIdentifier)) as only the PLIST's values seem to be resolved at build time, but not the keys.
I've added a sub-directory programmatically (to <containerPath>/Documents) so the container is not empty. However, this shouldn't matter as all the other apps' directories were initially empty, too.
Some Apple apps that appear in iCloud Drive do not have these entries in their Info.plist, e.g., Numbers and Pages.
iCloud is set up correctly and I can programmatically look into the ubiquity container using the URL returned by [[NSFileManager defaultManager] URLForUbiquityContainerIdentifier:nil];.
I am logged into an iCloud account where iCloud Drive is enabled. I can see my iCloud Drive content in the UIDocumentPickerViewController.
I use the iOS 8 beta 5 simulator (and Yosemite beta 5 to view the iCloud Drive directory on the Mac) (Edit/Note: This equally applies to beta 6)

This is how my Entitlements file looks like (relevant parts only)

<key>com.apple.developer.icloud-container-identifiers</key>
<array>
    <string>iCloud.$(CFBundleIdentifier)</string>
</array>
<key>com.apple.developer.icloud-services</key>
<array>
    <string>CloudDocuments</string>
</array>
<key>com.apple.developer.ubiquity-container-identifiers</key>
<array/>

I've set this up using Xcode's UI in the Capabilities section. I don't get why the last key doesn't have an entry, but adding <string>iCloud.$(CFBundleIdentifier)</string> doesn't help. Instead, it makes Xcode complain in the Capabilities UI, so I've removed it. Edit/Note: In Xcode beta 6, this has been fixed, i.e., the ubiquity container identifier needs to be set and Xcode can fix that for you.

Original Questions: So... is it a bug? Does it not work yet? Am I doing it wrong? I couldn't find a known issue in the release notes.

Edit:

Two more things that I've tried:

Adding the (optional) NSUbiquitousContainerName key (+ value) to the container-specific dictionary, as suggested by Erikmitk.
Adding only the NSUbiquitousContainerIsDocumentScopePublic key/value to the PLIST root dictionary rather than the container-specific dictionary, as it's done in one of the WWDC sample apps (look for NewBox).

回答1:

I was experiencing a similar problem with my application. I was able to make this work by doing the following:

Add the NSUbiquitousContainers setting to my Info.plist file according to documentation here https://developer.apple.com/library/prerelease/ios/documentation/General/Conceptual/ExtensibilityPG/FileProvider.html. Here is the relevant code:

<dict>
    <!-- ... other top-level Info.plist settings ... -->
    <key>NSUbiquitousContainers</key>
    <dict>
        <key>iCloud.com.example.MyApp</key>
        <dict>
            <key>NSUbiquitousContainerIsDocumentScopePublic</key>
            <true/>
            <key>NSUbiquitousContainerSupportedFolderLevels</key>
            <string>Any</string>
            <key>NSUbiquitousContainerName</key>
            <string>MyApp</string>
        </dict>
    </dict>
</dict>

Important! I then changed the above NSUbiquitousContainerSupportedFolderLevels string value from Any to One
```
<key>NSUbiquitousContainerSupportedFolderLevels</key>
<string>One</string>
```
Next, and last, I had to change CFBundleVersion to a higher version. I also bumped the CFBundleShortVersionString to a new version as well.

Built and ran and after that, the folder with my applications icon appeared properly in iCloud Drive! Hope this helps!

回答2:

When you edited the Info.plist, maybe you forgot to bump up the bundle version number? This is a requirement as per WWDC session #234.

回答3:

The catch is to call [[NSFileManager defaultManager] URLForUbiquityContainerIdentifier:nil]; (or with another container identifier if it's not the default one) at least once (not per launch, but presumably per version, or when changing one of the respective PLIST entries) in order to initialize the directory. I reckon this step needs to be combined with an increase of the bundle version number, as suggested in roop's answer.

I notice my question may have been confusing in that respect, as I mentioned being able to look into the documents directory* programmatically using the API in question. However, I removed that code from the app later, maybe before getting the rest of the setup right. I'm not going to write into the documents directory directly, only through the Document Picker. Therefore, there hasn't been any need to get the URL.

If you just need a Document Picker to read/store files from/in iCloud Drive or other apps' document directories, there's no need to call URLForUbiquityContainerIdentifier:. Only if you want your app to have its own ubiquity container (and potentially expose it in iCloud Drive and the Document Picker), the steps mentioned in the original post and the call to URLForUbiquityContainerIdentifier: are necessary.

*When mentioning the documents directory, I'm always referring to the one in the ubiquity container, not the local one.

回答4:

It seems, changing the CFBundleVersion will let it work.

I think you can try it. I got this from Apple Developer Forums.

Hope this work for you.

回答5:

In my case (Xcode 7 and iOS 9), the only thing which made it works, after multiple tries, was just use a new bundle identifier (you don't have to change the cloud container identifier, just be sure to select the container you want to use in the Apple Developer Member Centre and to specify in Xcode a custom container instead of the default).

In fact, that means the first time you run your application, the NSUbiquitousContainers section of the info.plist has to be set up. If you set it afterwards as a second step, it won't work...

回答6:

After dorking around with this all morning, reading all the posts, making all the changes, the key thing that finally worked for me was, as Yet Another Code Maker stated, changing the bundle ID. I think once it has created a container for a bundle, you can't go back and change the visibility of it to have it appear in Finder. I had tried all the different info.plist values but nothing worked until I changed to a new bundle name and forced the system to create a new one. By the way, I didn't see this noted anywhere but the bundle name, the NSUbiquitousContainer name and the NSUbiquitousContainerName can all be different - which is what I did in my case. After spending so much time on this, I figured I would go ahead and put a simple sample app on GitHub in case anyone is still having problems debugging their iCloud folder appearing in Finder - you can find it here. All the required steps are outlined in the README.

回答7:

Couldn't find any documentation, but trial and error, I found that:

[[NSFileManager defaultManager] URLForUbiquityContainerIdentifier:@"com.apple.CloudDocs"];

Gives you the base URL for the drive as seen in the picker. Using this base URL I was able to save files in my app and see it on the iCloud drive within Yosemite.

Edit 14.8.14

I tried your plist settings:

<key>NSUbiquitousContainers</key>
<dict>
    <key>iCloud.net.redacted.docTest</key>
    <dict>
        <key>NSUbiquitousContainerIsDocumentScopePublic</key>
        <true/>
        <key>NSUbiquitousContainerSupportedFolderLevels</key>
        <string>Any</string>
    </dict>
</dict>

In my little throwaway test app "docTest" it does indeed expose the empty Documents directory in Yosemite and in the document picker.

Screenshot http://spring-appstudio.com/picker-view.png

回答8:

The .plist entry on this documentation page has an additional entry:

<key>NSUbiquitousContainerName</key>
<string>MyApp</string>

Maybe the missing name is prohibiting it from showing up.

回答9:

Same problem occurred to my OSX app.

It is seemed that NSUbiquitousContainers setting works only in the creation time of the iCloud containers. So I tried with new Apple ID(for preparing clean iCloud environment), it becomes to work.

回答10:

Just wanted to emphasize one of the OP's discoveries that fixed it for me:

I've also recognised that you need to hard-code the bundle identifier (i.e., don't use iCloud.$(CFBundleIdentifier)) as only the PLIST's values seem to be resolved at build time, but not the keys.

You need to hard code the bundle id. Also update the version.

(I didn't notice this in the question until I went through all the answers).

回答11:

I know this is an old thread but just in case someone runs into the same issue: Only way for me to get my Container folder to be visible in iCloud Drive (after trying all the above suggestions) was to have my app create a temporary file in the Documents folder. As soon as I did that the Container Folder (and the file I created) showed up on my Mac. If this is really the case that I have to create a file to make this folder visible then this would be a bit annoying because my app is a read only app (only reads files added by the user to the Container Folder). The Container Folder needs to be visible as soon as the app is launched for the first time. I guess I will have to detect the first launch.

来源：https://stackoverflow.com/questions/25203697/exposing-an-apps-ubiquitous-container-to-icloud-drive-in-ios-8

标签

icloud

ios8

entitlements

icloud-api

info-plist