Issues with losing touch events

[GoogleCodeExporter]

If the touch up/down state changes and the remaining/new points don't move, the 
screen appears to have lost one or more points: if pt 1 is down, and pt 2 is 
added precisely without moving either point, the visualizer won't display pt 2 
until you actually move pt 2.

Alternatively, with pt 1 & 2 down, lift pt 2 without moving pt 1. It will look 
like there are no points down until pt 1 is moved.

Original issue reported on code.google.com by luke.hutch on 22 Apr 2012 at 4:47

[GoogleCodeExporter]

Another bug report from 김한결: 이 프로그램은 2점 터치를 했을 
때 한 손가락을 떼면 그 외의 점도 같이 떨어지는 오류가 
있습니다.

Effectively this translates to "If you lift one finger, both touch points come 
up on Nexus S"

Original comment by luke.hutch on 22 Apr 2012 at 4:54

[GoogleCodeExporter]

Another user report: 
With 2 points, there are no pointer IDs; after lifting off one finger from 
touch point 4 and then the other from 3, then putting down one finger again, 
the single touch point has a ID.

Original comment by luke.hutch on 22 Apr 2012 at 4:55

[GoogleCodeExporter]

Got another related report from Garnet: 

I do have one quick question/observation.  I only have a Nexus One to
test my multitouch.  I am aware and understand a variety of issues
with that touchscreen.  What I see happening however with both your
visualizer and my app is something I had not known about.  When I have
two fingers down, your controller correctly reports two points.  When
I remove the second point, I actually get two events, one reporting a
new numPoints = 0, and then a few milliseconds later the correct
numPoints = 1.  Like this:

I/caJoystick(24296): *****************
I/caJoystick(24296): time: 1317005694145       <-------- this is where
I put the second finger down
I/caJoystick(24296): numpoints = 2
I/caJoystick(24296): joystickX = 90  joystickY = 146
I/caJoystick(24296): button0:128
I/caJoystick(24296): button1:0
I/caJoystick(24296): *****************
I/caJoystick(24296): time: 1317005696679
I/caJoystick(24296): numpoints = 0                    <--------- this
is when I remove that second finger but still have the first one down
I/caJoystick(24296): joystickX = 127  joystickY = 127
I/caJoystick(24296): button0:0
I/caJoystick(24296): button1:0
I/caJoystick(24296): *****************
I/caJoystick(24296): time: 1317005696682
I/caJoystick(24296): numpoints = 1                    <---------  and
then the correct value comes in 3 milliseconds later!
I/caJoystick(24296): joystickX = 87  joystickY = 143
I/caJoystick(24296): button0:0
I/caJoystick(24296): button1:0
I/caJoystick(24296): *****************

I can see that your multitouch visualizer from the market has the same
issue because removing the second finger from the screen causes the
text to appear on the display (as if no fingers were on the screen)
for an almost imperceptible time.  Just a flash.

Can I assume that this is another neat feature of the nexus one or is
there any chance that there is a bug in your controller?  I can use a
timer to suppress the spurious numpoints = 0 but that is rather
hackish.  Thought I'd check with you first.  I couldn't find any
reference to this specific nexus one issue on the net.

Original comment by luke.hutch on 22 Apr 2012 at 4:58

[GoogleCodeExporter]

hi
same problem on a motorola xoom
When lifting a finger without moving the others, the API loses the touch points.
Example : point1 point2 point3 down
Lift point3 without moving the others fingers (you must be careful and precise 
!)
Result: the 2 remaining points are lost, but they are displayed again if the 
fingers are moved a little bit

Original comment by [email protected] on 15 May 2012 at 7:49