Question

Mac OS X 10.6 — Cocoa

I m using global event monitor for displaying status item menu using custom keyboard shortcut:

globalEventMonitor = [NSEvent addGlobalMonitorForEventsMatchingMask:NSKeyDownMask handler:^(NSEvent *event)
{
    if ([event keyCode] == kVK_F12)
    {
        [self handleGlobalShortcut];
        // How to prevent system beep?
    }
}];

This solution is working but the system generates a beep sound every time when user presses F12 and active application doesn t respond to this key event.

Is there any way to prevent an active application from beeping every time I use a global shortcut?

Answer 1

In your event monitor, you need to activate your app so that it will receive the key event.

[NSApp activateIgnoringOtherApps:YES];

Otherwise, the event will be passed to the current active application (which will beep).

EDIT: It looks like this won t work.

According to the docs "you cannot modify or otherwise prevent the event from being delivered to its original target application".

So Snow Leopard s new addGlobalMonitorForEventsMatchingMask API is not suitable for handling hot keys. You will need to continue to use the old Carbon RegisterEventHotKey API. Fortunately, this API is compatible with 64-bit Cocoa on Snow Leopard.

Answer 2

Seems impossible. Beeping is the default behavior of [NSResponder noResponderFor]. So an application beep unless it override that behavior by adding a last responder, which is unlikely doable from outside the application.

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