The 10.6.3 os x update broke simulated key-presses for Nestopia.

Question

The iPhone app that I released is a wireless game controller, it translates touches on the device into key-presses on the networked Mac. This allowed for playing emulator (e.g. Nestopia) games using the iPhone as a controller. Of course, the day that I released it coincided with an os x update. After installing this update, the simulated key-presses no longer work in Nestopia! The crazier thing is, when I go to 'File > Open' within Nestopia, I can cycle through the file list by hitting the up-arrow on my iphone controller; i.e. the simulated key-presses work in menu items, but not in the game itself. The code that I use to simulate keys is below. Given the list of changes here, can anyone identify which change would cause this problem?

Thanks!!

#define UP  false
#define DOWN true

-(void)sendKey:(CGKeyCode)keycode andKeyDirection:(BOOL)keydirection{
  CGEventRef eventRef = CGEventCreateKeyboardEvent(NULL, keycode, keydirection);
  CGEventPost(kCGSessionEventTap, eventRef);
  CFRelease(eventRef);
}

Answer 1

I think it's a problem with your code and not with 10.6.3. I have an app I'm writing that simulates key presses, and I've upgraded to 10.6.3, and my simulated key presses still work just fine.

Here's what I'm doing:

CGEventSourceRef source = CGEventSourceCreate(kCGEventSourceStateCombinedSessionState);
CGEventRef keyDownPress = CGEventCreateKeyboardEvent(source, (CGKeyCode)keyCode, YES);
CGEventSetFlags(keyDownPress, (CGEventFlags)flags);
CGEventRef keyUpPress = CGEventCreateKeyboardEvent(source, (CGKeyCode)keyCode, NO);

CGEventPost(kCGAnnotatedSessionEventTap, keyDownPress);
CGEventPost(kCGAnnotatedSessionEventTap, keyUpPress);

CFRelease(keyDownPress);
CFRelease(keyUpPress);
CFRelease(source);

Answer 2

The author of Mac Nestopia is using an older call, GetKeys(), to capture key events. As of 10.6.3, GetKeys does not catch generated key presses using the methods detailed in this post. The workaround I found was to use this instead:

-(void)sendKey:(CGKeyCode)keycode andKeyDirection:(BOOL)keydirection{
  AXUIElementRef axSystemWideElement = AXUIElementCreateSystemWide();
  AXError err = AXUIElementPostKeyboardEvent(axSystemWideElement, 0, keycode, keydirection);
  if (err != kAXErrorSuccess)
    NSLog(@" Did not post key press!");
}

Huge thanks to Richard Bannister for his quick email responses!