From iPhone OS to cocoa on OSX...

Question

Hi - this is quite a basic OSX/cocoa question.

I come from an iPhone OS development background. I'm now trying to write apps for OSX, but I don't understand where cocoa on OSX decides where the program gets control.

I can see the main function, but where does program control go from there? Say for example I want to programatically create a window with an NSView in it once the app has finished launching - how would I do that? There is no app delegate created that I can see, in iPhone OS I would wait for the - (void) applicationDidFinishLaunching:(UIApplication *)application

method to be called. I really don't want to use the Interface Builder or NIB files to setup my window/view. How would I go about this?

Any help would be much appreciated -

Cheers, David

Answer 1

It's much the same as the iPhone. In your application controller class, override NSApplication's applicationDidFinishLaunching delegate method. If you used the standard Xcode project template your app controller is already instantiated in your Interface Builder MainMenu.xib and set to be the application's delegate; if not you'll need to drag it in there and set up those connections yourself.

Speaking more generally, an OS X app begins its life in the main method, where Cocoa will automatically set up your application's run loop and load the .xib file you specify in Info.plist. This xib is usually where your application controller is instantiated. By overriding one of the methods such as +initialize, -init, -applicationWillFinishLaunching or -applicationDidFinishLaunching (which all have subtly different behaviors) you can load additional controllers and nibs with objects that interact with the run loop at a future date, so you can continue to execute code after your launch method has finished.