OSX: Prevent an window from closing when user hits cmd+w key

Question

In my MAC app, in one use case, I prompt an window to the user and give him 2 options (say buttons Save and Cancel). I want to force the user to select either of the 2 buttons to close the window.

But currently I find that if the user hits "Command + w" key when window has the focus, the window gets closed. In the .xib resource file, I uncheck the "close" option but that only disables the close option in the window UI.

How do I make sure that my window ignores the "Command+w" key and stays as is without closing.

Have also tried removing the notification by adding below code in awakeFromNib method but did not help.

[[NSNotificationCenter defaultCenter] removeObserver:NSWindowWillCloseNotification ];

Have also tried to implement "windowShouldClose" delegate method and return NO, but this method is never called. The documentation too says that this method is not reliable.

visibleman visibleman · Accepted Answer · 2015-07-15T01:15:36

I recently had to solve a similar problem. I'm not sure that this is the 'right' way to do it. But it worked for my purposes, and might work for you.

By default, I think, the 'Close Window' (CMD+W) menu item is bound to the action 'performClose' on first-responder. If you remove this binding and instead bind to a custom IBAction on your application delegate or main window controller, it allows you to conditionally call the close method of the current key-window if it is not matching the instance that you want to keep alive.

@property (strong, nonatomic) MyWindowController *unstoppable;
-(IBAction)killActiveWindow:(id)sender
{   
    NSWindow *keyWindow = [[NSApplication sharedApplication]keyWindow];
    if ([keyWindow isNotEqualTo: unstoppable.window]){
        NSLog(@" CMD+W Closing Window %@",keyWindow.title);
        [keyWindow close];
    }
}

OSX: Prevent an window from closing when user hits cmd+w key

2 Answers