How to make my app stay on top of fullscreen apps

Question

I have an app which must always stay on top of other applications. I'm currently using the setLevel property for the main window to keep it on top of other desktop applications.

I'm trying to fix my app so it can also stay on top of full-screen apps in Lion. Any ideas on how this can be done?

The Application delegate looks like this:

#import "alwaysOnTopAppDelegate.h"

@implementation alwaysOnTopAppDelegate

@synthesize window;

- (void)applicationDidFinishLaunching:(NSNotification *)aNotification
{
    [window setLevel:NSFloatingWindowLevel];
}

@end

Answer 1

Found the answer: The app delegate should look like this:

- (void)applicationDidFinishLaunching:(NSNotification *)aNotification
{
    [window setLevel:kCGMainMenuWindowLevel-1];
    [window setCollectionBehavior:NSWindowCollectionBehaviorStationary|NSWindowCollectionBehaviorCanJoinAllSpaces|NSWindowCollectionBehaviorFullScreenAuxiliary];
}

Answer 2

The way that Yoink works is simple: Just set "Application is Agent (UIElement)" to YES in the Info.plist for your application. It will mean it doesn't show in the dock etc. but that's probably fine for an auxiliary window (well, it was for me!). It probably makes sense to provide a menu bar item in this case so the user can stop the application easily.