Get the current wallpaper in Cocoa

Question

I'm using this code to get the current wallpaper:

NSURL *imageURL = [[NSWorkspace sharedWorkspace] desktopImageURLForScreen:[NSScreen mainScreen]];

This works fine, but when i set a folder of pictures to be the wallpaper(As shown in the picture), the imageURL is a directory, so how can i get the current wallpaper's USURL in this situation?

Answer 1

I've been trying to do the exact same thing. You can get the current desktop picture URL by:

1. Getting the current space UUID from the com.apple.spaces property list,
2. Searching the com.apple.desktop property list for the matching space,
3. Extracting the URL from the LastName property

I am still working on this, but the following code obtains the correct URL... sometimes. The main problem is that the property lists aren't updated frequently enough, and I haven't been able to force them to refresh (short of killing the dock). Let me know if you figure something out!

NSDictionary *spacesPLIST = (__bridge NSDictionary *)(CFPreferencesCopyAppValue(CFSTR("SpacesConfiguration"), CFSTR("com.apple.spaces")));
NSDictionary *desktopPLIST = (__bridge NSDictionary *)(CFPreferencesCopyAppValue(CFSTR("Background"), CFSTR("com.apple.desktop")));

NSArray *monitors = [spacesPLIST valueForKeyPath:@"Management Data.Monitors"];
NSInteger monitorIndex = 0;
if ([monitors count] > 1) {
    //search for main (or ask user to select)
}
NSDictionary *monitor = [monitors objectAtIndex:monitorIndex];
NSDictionary *spaces = [desktopPLIST valueForKey:@"spaces"];
NSString *currentSpaceUUID = [monitor valueForKeyPath:@"Current Space.uuid"];
NSDictionary *currentSpace = [spaces valueForKey:currentSpaceUUID];
NSURL *desktopPicturesDirectory = [NSURL fileURLWithPath:[currentSpace valueForKeyPath:@"default.ChangePath"] isDirectory:true];
NSString *desktopPictureName = [currentSpace valueForKeyPath:@"default.LastName"];
NSURL *desktopPictureURL = [NSURL URLWithString:desktopPictureName relativeToURL:desktopPicturesDirectory];
[[NSWorkspace sharedWorkspace] selectFile:[desktopPictureURL path] inFileViewerRootedAtPath:@""];