Strange behaviour when posting CGEvent to PSN
- by Ben Packard
If I set up a loop that posts some keyboard events to a PSN, I find that it works fine except for when first launched. The event only seems to post when i do something with the mouse manually - even just moving it slightly. Here's the details, if they help.
An external application has a list box of text lines, which I am reading by posting copy commands (and checking the pasteboard). Unfortunately this is my only way to get this text.
Sometimes, the application pulls focus away from the list, which I can detect. When this happens, the most reliable way to return focus is by sending a mouse event to click on a text field directly above the list, then send a 'tab' keyboard event to shift the focus onto the list.
So at launch, the loop runs fine, scrolling down the list and copying the text. When focus is shifted away, its is detected fine, and the events are sent to move focus back to the list. But nothing seems to happen. The loop continues detecting that focus has changed, but the events only work once I move the mouse. Or even just use the scroll wheel. Strange.
Once this has happened the first time, it works fine - each time focus moves, the PSN events switch it back without me having to do anything at all.
Here's the code that runs in the loop - verified as working:
//copy to pasteboard - CMD-V
e3 = CGEventCreateKeyboardEvent(NULL, (CGKeyCode)8, true);
CGEventSetFlags(e3, kCGEventFlagMaskCommand);
CGEventPostToPSN(&psn, e3);
CFRelease(e3);
e4 = CGEventCreateKeyboardEvent(NULL, (CGKeyCode)8, false);
CGEventPostToPSN(&psn, e4);
CFRelease(e4);
//move cursor down
e1 = CGEventCreateKeyboardEvent(NULL, (CGKeyCode)125, true);
CGEventPostToPSN(&psn, e1);
CFRelease(e1);
e2 = CGEventCreateKeyboardEvent(NULL, (CGKeyCode)125, false);
CGEventPostToPSN(&psn, e2);
CFRelease(e2);
And here's where I switch focus, also working (except when first required):
//click in text input box - point is derived earlier
e6 = CGEventCreateMouseEvent(NULL, kCGEventLeftMouseDown, point, 0);
CGEventPostToPSN(&psn, e6);
CFRelease(e6);
e7 = CGEventCreateMouseEvent(NULL, kCGEventLeftMouseUp, point, 0);
CGEventPostToPSN(&psn, e7);
CFRelease(e7);
//press tab key to move to chat log table
CGEventRef e = CGEventCreateKeyboardEvent(NULL, (CGKeyCode)48, true);
//CGEventPost(kCGSessionEventTap, e);
CGEventPostToPSN(&psn, e);
CFRelease(e);
CGEventRef e11 = CGEventCreateKeyboardEvent(NULL, (CGKeyCode)48, false);
CGEventPostToPSN(&psn, e11);
CFRelease(e11);
