Question

Is there a way, in either Applescript or Objective-C, to detect when a certain application opens? My goal is to add a feature to an application that I’m working on to show a message whenever “QuickTime Player” opens, but I haven’t found a anything in the Apple developer documents that shows how to do anything like this.

Answer 1

This is pretty simple with Objective-C. Here’s the code:

Register for the proper notifications from NSWorkspace:

- (void)applicationDidFinishLaunching:(NSNotification *)aNotification
{
    //Fetch the notification center from the workspace
    NSNotificationCenter* center = [[NSWorkspace sharedWorkspace] notificationCenter];

    [center addObserver:self selector:@selector(newApplicationDidLaunch:) name:NSWorkspaceDidLaunchApplicationNotification object:nil];

    [center addObserver:self selector:@selector(newApplicationWillLaunch:) name:NSWorkspaceWillLaunchApplicationNotification object:nil];

}

Then, add your selectors for the notification. The userInfo dictionary of the notification will hold everything you need to know:

-(void)newApplicationDidLaunch:(NSNotification*)notification {

    NSDictionary* userInfo = notification.userInfo;
    //Do what you want here after application launch.
}

-(void)newApplicationWillLaunch:(NSNotification*)notification {

    NSDictionary* userInfo = notification.userInfo;
    //Do what you want here to prepare for application launch.
}

Hope that helps.