保存到watchOS 2文件夹

Question

My iOS app sends a database to WatchKit (watchOS 2) . In WatchKit i use the following code to get the watch document folder to save the new file in:

NSURL* fileURL = [[[[NSFileManager defaultManager] URLsForDirectory:NSDocumentDirectory inDomains:NSUserDomainMask] lastObject] URLByAppendingPathComponent:@"MyDatabase.sqlite"];

This results in an URL:

@"file:///var/mobile/Containers/Data/PluginKitPlugin/47E13085-9030-4ED2-906F-01CBA323F07A/Documents/MyDatabase.sqlite"

However, when I call the function:

[[NSFileManager defaultManager] replaceItemAtURL:fileURL withItemAtURL:url backupItemName:nil options:0 resultingItemURL:nil error:&error];

It throws an error saying:

Error Domain=NSCocoaErrorDomain Code=512 "The file “MyDatabase.sqlite” couldn't be saved in the folder “Documents”." Error Domain=NSCocoaErrorDomain Code=513 "You don't have permission to save the file “MyDatabase.sqlite”

How can I find a folder I'm allowed to save to? Naturally this code worked fine in the simulator so I assume I'm missing something not too obvious.

BR Frederik

Answer 1

I believe your issue is that apple watch extensions can't save files to their documents dir. I was able to save files by using app Groups. Add an app group to your entitlements and then you should be able to write to the following dir:

let path = NSFileManager.defaultManager().containerURLForSecurityApplicationGroupIdentifier("group.my.cool.watch.app")