Simulating key press events in Mac OS X

Question

I\'m writing an app where I need to simulate key press events on a Mac, given a code that represents each key. It seems I need to use the CGEventCreateKeyboardEvent

Answer 1

Here's code to simulate a Cmd-S action:

CGKeyCode inputKeyCode = kVK_ANSI_S;
CGEventSourceRef source = CGEventSourceCreate(kCGEventSourceStateCombinedSessionState);
CGEventRef saveCommandDown = CGEventCreateKeyboardEvent(source, inputKeyCode, YES);
CGEventSetFlags(saveCommandDown, kCGEventFlagMaskCommand);
CGEventRef saveCommandUp = CGEventCreateKeyboardEvent(source, inputKeyCode, NO);

CGEventPost(kCGAnnotatedSessionEventTap, saveCommandDown);
CGEventPost(kCGAnnotatedSessionEventTap, saveCommandUp);

CFRelease(saveCommandUp);
CFRelease(saveCommandDown);
CFRelease(source);

A CGKeyCode is nothing more than an unsigned integer:

typedef uint16_t CGKeyCode;  //From CGRemoteOperation.h

Your real issue will be turning a character (probably an NSString) into a keycode. Fortunately, the Shortcut Recorder project has code that will do just that in the SRKeyCodeTransformer.m file. It's great for transforming a string to a keycode and back again.

Answer 2

Just in case some one needs a Swift version:

XCode 7.3 and Swift 2.2:

let event1 = CGEventCreateKeyboardEvent(nil, 0x09, true); // cmd-v down
CGEventSetFlags(event1, CGEventFlags.MaskCommand);
CGEventPost(CGEventTapLocation.CGHIDEventTap, event1);

let event2 = CGEventCreateKeyboardEvent(nil, 0x09, false); // cmd-v up
CGEventSetFlags(event2, CGEventFlags.MaskCommand);
CGEventPost(CGEventTapLocation.CGHIDEventTap, event2);

Code above simulates CMD-V pressed then released(AKA: paste).