This bug report was migrated from our old Bugzilla tracker.

Reported in version: HG 2.1
Reported for operating system, platform: Android (All), All

Comments on the original bug report:

On 2014-05-22 19:02:57 +0000, Sylvain wrote:

Hello,

This one is critical :)

If you play with the TouchScreen with +3 fingers randomly / pressing simultaneously all fingers.

You triggers FINGER DOWN events, but not always all the associated FINGER UP events.

So, after a while SDL_GetNumFingers() can report a wrong number of fingers pressed !

The explanation is hidden there : http://developer.android.com/reference/android/view/MotionEvent.html

Each pointer has a unique id that is assigned when it first goes down (indicated by ACTION_DOWN or ACTION_POINTER_DOWN).
A pointer id remains valid until the pointer eventually goes up (indicated by ACTION_UP or ACTION_POINTER_UP) or when the gesture is canceled (indicated by ACTION_CANCEL).

in ACTION_CANCEL :

The current gesture has been aborted. You will not receive any more points in it. You should treat this as an up event, but not perform any action that you normally would.
Constant Value: 3 (0x00000003)

A working patch : in SDLActivity.java (in onTouch())

< case MotionEvent.ACTION_CANCEL:
< for (i = 0; i < pointerCount; i++) {
< pointerFingerId = event.getPointerId(i);
< x = event.getX(i) / mWidth;
< y = event.getY(i) / mHeight;
< p = event.getPressure(i);
< SDLActivity.onNativeTouch(touchDevId, pointerFingerId, MotionEvent.ACTION_UP, x, y, p);
< }
< break;

Cheers,

Sylvain

On 2014-05-24 08:12:34 +0000, Sylvain wrote:

Also ..
it does not appear with (old) Nexus7.
it appears with HTC ONE.

On 2014-06-16 02:33:07 +0000, Sam Lantinga wrote:

Fixed, thanks!
https://hg.libsdl.org/SDL/rev/e7abd1102676