Question

My app have Preferences window. I open it using this code

- (IBAction)openPreferences:(id)sender {

    NSWindowController *windowController = [[NSWindowController alloc] initWithWindowNibName:@"Preferences"];
    [windowController window];
}

If press command, again-again and again new Preferences window will be opened again-again and again…

How open only one window? Thanks!

Answer 1

Make windowController a instance variable of your AppDelegate and change your open preferences to

- (IBAction)openPreferences:(id)sender
{
    if( windowController == nil )
        windowController = [[NSWindowController alloc] initWithWindowNibName:@"Preferences"];
    [windowController showWindow:sender];
}