IPhone SDK Multi-Touch Bug?

Question

Hi,
I'm trying to handle multi-touch events and this is the bug I'm seeing ( using SDK beta 4 ):
The first touch I make has a valid position ( using locationInView instance method ). However, any touches made while the first touch is being held down have invalid positions ( 0,0 ). Here's my code:
// Handle touch events
- (void)touchesChangedWithEvent:(UIEvent*)event
printf( "* TOUCHES CHANGED EVENT!\n" );
NSSet *touches = [event allTouches];
for( UITouch *touch in touches )
// Grab the location of the touch
CGPoint touchPos = [touch locationInView:self];
// Touch began
if( touch.phase == UITouchPhaseBegan )
printf( "**** TOUCH BEGAN AT ( %f, %f )\n", touchPos.x, touchPos.y );
iRKInputSetNewTouch();
iRKInputSetPos( touchPos.x, touchPos.y );
// Touch moved
else if( touch.phase == UITouchPhaseMoved )
printf( "**** TOUCH MOVED AT ( %f, %f )\n", touchPos.x, touchPos.y );
iRKInputSetPos( touchPos.x, touchPos.y );
// Touch stationary
else if( touch.phase == UITouchPhaseStationary )
printf( "**** TOUCH STATIONARY AT ( %f, %f )\n", touchPos.x, touchPos.y );
iRKInputSetPos( touchPos.x, touchPos.y );
// Touch ended
else if( touch.phase == UITouchPhaseEnded )
printf( "**** TOUCH ENDED AT ( %f, %f )\n", touchPos.x, touchPos.y );
iRKInputClearTouch();
iRKInputResetPos();
Anyone else seeing this? Or am I doing something wrong?
Also, any help on displaying source code would be appreciated too
Thanks!
- Bryan

Answer 1

So, with the following multiple event code I seem to be getting an even worse problem: Multiple touches aren't even triggering the events and my first touch is always the only UITouch in the set ( even when I have two or three fingers touching the screen ). This is on the device using SDK beta 4.
// Handles the start of a touch
- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
printf( "* TOUCH BEGAN
for( UITouch *touch in touches )
// Grab the location of the touch
CGPoint touchPos = [touch locationInView:self];
// Touch began
//if( touch.phase == UITouchPhaseBegan )
printf( "**** TOUCH BEGAN AT ( %f, %f )
", touchPos.x, touchPos.y );
iRKInputSetNewTouch();
iRKInputSetPos( touchPos.x, touchPos.y );
// Handles the continuation of a touch.
- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event
printf( "* TOUCH MOVED
for( UITouch *touch in touches )
// Grab the location of the touch
CGPoint touchPos = [touch locationInView:self];
// Touch moved
//if( touch.phase == UITouchPhaseMoved )
printf( "**** TOUCH MOVED AT ( %f, %f )
", touchPos.x, touchPos.y );
iRKInputSetPos( touchPos.x, touchPos.y );
// Handles the end of a touch event.
- (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event
printf( "* TOUCH ENDED
for( UITouch *touch in touches )
// Grab the location of the touch
CGPoint touchPos = [touch locationInView:self];
// Touch ended
//if( touch.phase == UITouchPhaseEnded )
printf( "**** TOUCH ENDED AT ( %f, %f )
", touchPos.x, touchPos.y );
iRKInputClearTouch();
iRKInputResetPos();
So when this is run and press the screen I get correct messages output to the console telling me a touch began / moved with the correct position. However, when I keep that press held and press somewhere else I get no other messages. When I move the first touch ( while keeping both touches held to the screen ) it gives me correct messages again but yet it's the only UITouch object in "touches".
Anyone else seeing problems with this?
Any help would be great! Thanks!
- Bryan