Question

I’m trying to change my windows content, from other class , that is subclass of NSViewController.I’m trying code below, but it doesn’t do anything.

[NSApplication sharedApplication]mainWindow]setContentView:[self view]]; //code in NSViewController

[NSApplication sharedApplication]mainWindow] // returns null

I tried to add

[window makeMainWindow];

in App Delegate class, but it won’t help.

Did I miss something?

P.S. Also I’m using code below to call any delegate function in my class,

 [(appDelegate *) [[NSApplication sharedApplication]delegate]MyMethod];

but I wonder is there something better, wihtout importing delegate class. Something like this

[[NSApplication sharedApplication]delegate]MyMethod];

(it gives warning)

Answer 1

For the mainWindow method the docs say:

This method might return nil if the application’s nib file hasn’t finished loading, if the receiver is not active, or if the application is hidden.

I just created a quick test application and I placed the following code:

NSLog(@"%@", [[NSApplication sharedApplication] mainWindow]);

into my applicationDidFinishLaunching:aNotification method, and into an action method which I connected to a button in the main window of my application.

On startup, the mainWindow was nil, but when I click the button (after everything is up and running and displayed), the mainWindow was no longer nil.

NSApplication provides other methods which you may be useful to you:

• - windows – an array of all the windows;
• – keyWindow – gives the window that is receiving keyboard input (or nil);
• – windowWithWindowNumber: – returns a window corresponding to the window number – if you know the number of the window whose contents you wish to replace you could use this;
• – makeWindowsPerform:inOrder: – sends a message to each window – you could use this to test each window to see if it’s the one you are interested in.

With regard to calling methods on the delegate, what you say gives a warning works fine for me. For example, this works with no warnings:

NSLog(@"%@", [[[NSApplication sharedApplication]delegate] description]);

What exactly is the warning you receive? Are you trying to call a method that doesn’t exist?