Convert Virtual Key Code to unicode string
- by Joshua Weinberg
I have some code I've been using to get the current keyboard layout and convert a virtual key code into a string. This works great in most situations, but I'm having trouble with some specific cases. The one that brought this to light is the accent key next to the backspace key on german QWERTZ keyboards. http://en.wikipedia.org/wiki/File:KB_Germany.svg
That key generates the VK code I'd expect kVK_ANSI_Equal but when using a QWERTZ keyboard layout I get no description back. Its ending up as a dead key because its supposed to be composed with another key. Is there any way to catch these cases and do the proper conversion?
My current code is below.
TISInputSourceRef currentKeyboard = TISCopyCurrentKeyboardInputSource();
CFDataRef uchr = (CFDataRef)TISGetInputSourceProperty(currentKeyboard, kTISPropertyUnicodeKeyLayoutData);
const UCKeyboardLayout *keyboardLayout = (const UCKeyboardLayout*)CFDataGetBytePtr(uchr);
if(keyboardLayout)
{
UInt32 deadKeyState = 0;
UniCharCount maxStringLength = 255;
UniCharCount actualStringLength = 0;
UniChar unicodeString[maxStringLength];
OSStatus status = UCKeyTranslate(keyboardLayout,
keyCode, kUCKeyActionDown, 0,
LMGetKbdType(), kUCKeyTranslateNoDeadKeysBit,
&deadKeyState,
maxStringLength,
&actualStringLength, unicodeString);
if(actualStringLength > 0 && status == noErr)
return [[NSString stringWithCharacters:unicodeString length:(NSInteger)actualStringLength] uppercaseString];
}
