iOS touch event notifications (private API)

Question

It's possible to simulate touch events on iOS, and you can receive various system wide notifications when in the background using CTTelephonyCenterAddObserver and CFNotificationCenterAddObserver, eg:

I've yet to find a way to get touch notifications while in the background though. Is there a "touch event" that can be used with CFNotificationCenterAddObserver, a different notification center that can be used, or a completely different approach?

I'd be happy with low level touch information (eg. x, y coordinates and touch type), but higher level information (eg. key pressed, back button pressed etc) would be even better!

Perhaps this might help you http://stackoverflow.com/questions/8303235/is-it-possible-to-capture-touch-events-in-the-background-on-a-jailbroken-ios-dev. Also do a search for `GSEvents` — Rog, Mar 21 '13 at 01:08

score 18 · Accepted Answer · edited May 23 '17 at 12:18

18

You can use the IOHID stuff in IOKit to get the x, y coordinates.

#include <IOHIDEventSystem.h>

create IOHIDEventSystemClient:

void *ioHIDEventSystem = IOHIDEventSystemClientCreate(kCFAllocatorDefault);

register callback:

IOHIDEventSystemClientScheduleWithRunLoop(ioHIDEventSystem, CFRunLoopGetCurrent(), kCFRunLoopDefaultMode);
IOHIDEventSystemClientRegisterEventCallback(ioHIDEventSystem, handle_event, NULL, NULL);

unregister callback:

IOHIDEventSystemClientUnregisterEventCallback(ioHIDEventSystem, handle_event, NULL, NULL);
IOHIDEventSystemClientUnscheduleWithRunLoop(ioHIDEventSystem, CFRunLoopGetCurrent(), kCFRunLoopDefaultMode);

callback:

void handle_event (void* target, void* refcon, IOHIDServiceRef service, IOHIDEventRef event) {
   if (IOHIDEventGetType(event)==kIOHIDEventTypeDigitizer){
       IOHIDFloat x=IOHIDEventGetFloatValue(event, (IOHIDEventField)kIOHIDEventFieldDigitizerX);
       IOHIDFloat y=IOHIDEventGetFloatValue(event, (IOHIDEventField)kIOHIDEventFieldDigitizerY);
       int width = [[UIScreen mainScreen] bounds].size.width;
       int height = [[UIScreen mainScreen] bounds].size.height;
       NSLog(@"click : %f, %f", x*width, y*height) ;
   }
}

Also, you can check this out: IOHIDEventSystemCreate on iOS6 failed. Hope this helps.

EDIT: Please see the result from the log. Tested on iPhone 4 and 5.

void handle_event (void* target, void* refcon, IOHIDServiceRef service, IOHIDEventRef event) {
    NSLog(@"handle_event : %d", IOHIDEventGetType(event));
if (IOHIDEventGetType(event)==kIOHIDEventTypeDigitizer){
    IOHIDFloat x=IOHIDEventGetFloatValue(event, (IOHIDEventField)kIOHIDEventFieldDigitizerX);
    IOHIDFloat y=IOHIDEventGetFloatValue(event, (IOHIDEventField)kIOHIDEventFieldDigitizerY);
    NSLog(@" x %f : y %f", x, y);
//2013-03-28 10:02:52.169 MyIOKit[143:907] handle_event : 11
//2013-03-28 10:02:52.182 MyIOKit[143:907]  x 0.766754 : y 0.555023
}
}

edited May 23 '17 at 12:18

Community

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1

answered Mar 21 '13 at 14:54

pt2121

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Awesome! I'm getting the events, but my x,y values are enormous, eg: 1050201600.000000, 1052667392.000000. Any tips? – Ben Dowling Mar 28 '13 at 00:19
Have you checked x and y before multiplying? I am not in front of my Mac now but as far as I remember I got x and y in from of %. Eg if you touch around the top right corner, x = 0.9 and y 0.1. – pt2121 Mar 28 '13 at 02:19
Yeah the huge number is the x,y without multiplying. – Ben Dowling Mar 28 '13 at 03:30
OK. I'll get back to you when I have a mac. – pt2121 Mar 28 '13 at 04:17
On iOS6 I'm seeing the huge values still, eg: x 1064502784.000000 : y 1034551296.000000 :( – Ben Dowling Mar 31 '13 at 03:07
@BenDowling This is weird. I did test on iOS6. – pt2121 Mar 31 '13 at 03:13
Just downloaded your test project and built that and that does work exactly how you've described, so it must just be a problem with the code in my project - will dig into it. Thanks for all your help! – Ben Dowling Mar 31 '13 at 03:24
Good to hear that. Good luck! – pt2121 Mar 31 '13 at 03:25
It gives me error that 'IOHIDEventSystem.h' file not found ... any idea ? – Mihir Mehta Apr 11 '13 at 09:54
But how can capture multi touch events? – Suge Jul 08 '13 at 06:51
Does anybody got the answer for this question? I need to inject system wide touch in iOS8. I have already asked similar question here: http://stackoverflow.com/questions/26915920/ios8-touch-injection-programatically but nobody replied to it. I really need answer asap. – TechFlitter Nov 27 '14 at 22:04

iOS touch event notifications (private API)

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