Question

I want to be notified when the current application will change. I looked at NSWorkspace. It will send notifications only when your own application becomes active or loses the activity. I want to be informed about every application. How can I do this in Cocoa?

Answer 1

Thank you Jason. kEventAppFrontSwitched in Carbon Event Manager is the magic word

- (void) setupAppFrontSwitchedHandler {     EventTypeSpec spec = { kEventClassApplication,  kEventAppFrontSwitched };     OSStatus err = InstallApplicationEventHandler(NewEventHandlerUPP(AppFrontSwitchedHandler), 1, &spec, (void*)self, NULL);      if (err)         NSLog(@'Could not install event handler'); }  - (void) appFrontSwitched {     NSLog(@'%@', [[NSWorkspace sharedWorkspace] activeApplication]); } 

And the handler

static OSStatus AppFrontSwitchedHandler(EventHandlerCallRef inHandlerCallRef, EventRef inEvent, void *inUserData) {     [(id)inUserData appFrontSwitched];     return 0; }