[QT5.12.1][VirtualKeyboard] some keypresses get canceled



  • Hi,
    I have been noticing a really disturbing phenomena using virtualkeyboard:
    some keypresses get randomly "cancelled", otherwise, user presses on a button but nothing
    is displayed.
    It seems that, internally, the keypress gets canceled by the qt framework.
    I see the same problem with the "qt quick virtual keyboard" example provided with qt creator.

    For the record, the app is compiled for armv7, on a device equipped with a touchscreen.
    The qt documentation states that this event is "triggered" upon user request, but the app
    is not requesting it. There might some internal condition that generates this cancellation. What
    could these conditions be?

    Best regards,



  • Here's the answer in case anyone has the same problem:
    The project on which i am working relies on tslib input backend to capture events from touchscreen. In average, one of six samples retreived by tslib was "noisy" hence the problems explained above.
    Solution was to use variance tslib plugin which gets rid of "noise samples"


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