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I have a simple app that prints the coordinates of all the touches event. In the simulator it works great.

On my device (iPhone) it works great with up to two fingers. When I tap with three fingers in a fast sequence the event touchesCancelled is triggered.

Could someone please explain this to me? This is the code for printing (in case the problem lays there) that sits in my UIView.

-(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
{
    for (UITouch *touch in touches) {
        CGPoint location = [touch locationInView:touch.view];
        NSLog(@"Began  %f %f",  location.x, location.y);
    }
}


-(void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event
{  
    for (UITouch *touch in touches) {
        CGPoint location = [touch locationInView:touch.view];
        NSLog(@"Moved  %f %f",  location.x, location.y);
    }
}


-(void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event
{
    for (UITouch *touch in touches) {
        CGPoint location = [touch locationInView:touch.view];
        NSLog(@"Ended  %f %f",  location.x, location.y);
    }
}

-(void)touchesCancelled:(NSSet *)touches withEvent:(UIEvent *)event
{
    NSLog(@"Phase: Touches cancelled");

    for (UITouch *touch in touches) {
        CGPoint location = [touch locationInView:touch.view];
        NSLog(@"Cancelled  %f %f",  location.x, location.y);

    }
}

An example of sequence is this one:

Began  38.000000 263.000000
Began  173.500000 238.500000
Moved  41.500000 263.000000
Phase: Touches cancelled   <<<< third touch
Cancelled  41.500000 263.000000
Cancelled  173.500000 238.500000

Thank you.

twernt
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Ugo B
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  • Just to clarify. If you use three fingers without a 'fast sequence' does it still cancel or does it work correctly? – NJones Nov 22 '11 at 21:02
  • Sometimes touchesCancelled: is not called and that is usually when I use the three fingers "slowly". – Ugo B Nov 22 '11 at 23:42
  • It seems weird that there's a problem with just three touches... – Ugo B Nov 23 '11 at 17:56
  • Is there maybe a gesture recognizer listening and triggering touchesCancelled? I have implemented none... but maybe the iPhone does something automatically. – Ugo B Nov 23 '11 at 22:05

0 Answers0