Adding your directory <bundle_ID>. What is it?

Question

I'm having trouble writing a file to the AppSupport folder in Xcode 5 for iOS 7. What am I trying to do:

NSArray *paths = NSSearchPathForDirectoriesInDomains(NSApplicationSupportDirectory, NSUserDomainMask, YES);
NSString *plistPath = [[paths lastObject] stringByAppendingPathComponent:@"somedata.plist"];
if(plistData) {
    NSLog(@"PATH: %@", plistPath);
    BOOL success = [plistData writeToFile:plistPath atomically:YES];
    NSLog(@"SUCCESS: %hhd",success);
}
else {
    NSLog(@"ERROR CREATING PLIST: %@",error);
}

And I get NO as output:

PATH: /var/mobile/Applications/40954....7E3C/Library/Application Support/somedata.plist
SUCCESS: 0

Apple Documentation says:

Use the Application Support directory constant NSApplicationSupportDirectory, 
appending your <bundle_ID> for: …

What does adding your package_ID mean? Maybe there is another way that I should use? NSDocumentDirectory is not suitable for me, because this is the place for user files.

Answer 1

Saving is a NSApplicationSupportDirectorybit trickier than

Follow this sample Apple code to write files to this directory.

- (NSURL*)applicationDirectory
{
    NSString* bundleID = [[NSBundle mainBundle] bundleIdentifier];
    NSFileManager*fm = [NSFileManager defaultManager];
    NSURL* dirPath = nil;

    // Find the application support directory in the home directory.
    NSArray* appSupportDir = [fm URLsForDirectory:NSApplicationSupportDirectory
                                        inDomains:NSUserDomainMask];
    if ([appSupportDir count] > 0)
    {
        // Append the bundle ID to the URL for the
        // Application Support directory
        dirPath = [[appSupportDir objectAtIndex:0] URLByAppendingPathComponent:bundleID];

        //Modified code to write your plist file to the Application support dir
        NSString *plistPath = [dirPath stringByAppendingPathComponent:@"somedata.plist"];

        //Assuming plistData is pre-populated ivar
        //Else add your code to create plistData here 
        if(plistData) {
            BOOL success = [plistData writeToFile:plistPath atomically:YES];
            NSLog(@"SUCCESS: %hhd",success);
        }
        else {
            NSLog(@"ERROR CREATING PLIST: %@",error);
        }
    }
}