How to create a helper application for Mac App to start it on user login?

Question

In fact, I read the following document:

Applications can contain a helper application as a full application bundle, stored inside the main application bundle in the Contents/Library/LoginItems directory. Set either the LSUIElement or LSBackgroundOnly key in the Info.plist file of the helper application’s bundle.

I don't quite understand it, anyone knows how to do?

and also, what does this mean:

Note: Before calling the SMLoginItemSetEnabled function, first register with Launch Services by calling the LSRegisterURL function with the URL for the helper application bundle.

is there any example about how to use LSRegisterURL and SMLoginItemSetEnabled?

Answer 1

+ (void)startHelper {
    NSURL *helperURL = [[[NSBundle mainBundle] bundleURL] URLByAppendingPathComponent:@"Contents/Library/LoginItems/YourHelper.app" isDirectory:YES];
    OSStatus status = LSRegisterURL((CFURLRef)helperURL, YES);
    if (status != noErr) {
        NSLog(@"Failed to LSRegisterURL '%@': %jd", helperURL, (intmax_t)status);
    }


    Boolean success = SMLoginItemSetEnabled(CFSTR("com.yourcompany.helper-CFBundleIdentifier-here"), YES);
    if (!success) {
        NSLog(@"Failed to start Helper");
    }
}

Note that the Helper must be packaged with the main app in the "Contents/Library/LoginItems" directory. You will need to create it during the build and copy the helper there.