Running Dockless

While working on feature requests for DateLine recently, I needed to add the ability to run the app Dockless - that is, without a menu bar or Dock icon.

In 10.5 and later, you can simply add the following key to your info.plist file to let LaunchServices know that you want your app to run Dockless:

<key>LSUIElement</key>
<true/>

But what if you want to be able to control in a preference item whether you app is Dockless or not?

It turns out that there is no Cocoa way to do this and some Carbon code is necessary. After a bit of Google Fu, I found this handy article at codesorcery. Thanks go to Justin for posing the question and to Dan who provided the actual code.

The problem with the above article, though, is that the definitive solution is only posted in the comments. So in the interests of making it easier to get your app running Dockless, I have tidied it up into a method snippet and posted it below.

- (void) setDockStatus {
        // this should be called from the application delegate's applicationDidFinishLaunching
        // method or from some controller object's awakeFromNib method
        // Neat dockless hack using Carbon from <a href="http://codesorcery.net/2008/02/06/feature-requests-versus-the-right-way-to-do-it" title="http://codesorcery.net/2008/02/06/feature-requests-versus-the-right-way-to-do-it">http://codesorcery.net/2008/02/06/feature-requests-versus-the-right-way-...</a>
	if ([[NSUserDefaults standardUserDefaults] boolForKey:@"doShowInDock"]) {
		ProcessSerialNumber psn = { 0, kCurrentProcess };
		// display dock icon
		TransformProcessType(&psn, kProcessTransformToForegroundApplication);
		// enable menu bar
		SetSystemUIMode(kUIModeNormal, 0);
		// switch to Dock.app
		[[NSWorkspace sharedWorkspace] launchAppWithBundleIdentifier:@"com.apple.dock" options:NSWorkspaceLaunchDefault additionalEventParamDescriptor:nil launchIdentifier:nil];
		// switch back
		[[NSApplication sharedApplication] activateIgnoringOtherApps:TRUE];
	}
}