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 stackoverflow.com/questions/8303235/…. Also do a search for GSEvents — Rog

pt2121 pt2121 · Accepted Answer · 2013-03-21T14:54:59

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
}
}

iOS touch event notifications (private API)

1 Answers