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Weirdly opening Qt application on BeagleBone Black

  • Hello guys,

    I've cross-compiled a couple basic Qt applications to a BeagleBone Black (running Angstrom) using the following tutorial

    When i execute the app ./InitialGUITest -qws nothing at all happens.
    I've realized i need to press ctrl+alt+f2 to be able to see my application running, and then i cannot get back to the my default environment (ctrl+alt+BKSPACE or ctrl+atl+f1->7).
    Is this meant to execute like this?

    Also im using a touch-screen and the Qt app does not respond to the touch, although i can see a cursor visible AND the touchscreen does work in the default enviroment.
    How can i tell the app to use my touchscreen?

    Sorry if im a little vague or asking common-knowledge questions. Im new to linux and Qt.

  • Did you set the environment variables correctly?

    If you are using Qt with Tslib driver for TouchScreen you can set your variables like this:

    export TSLIB_FBDEVICE=/dev/fb0
    export TSLIB_TSDEVICE=/dev/input/event1
    export TSLIB_CALIBFILE=/etc/pointercal
    export QWS_MOUSE_PROTO=tslib:/dev/input/event1

    This will set your application to use touchscreen and display device if your driver was compiled correctly.


  • Thanks for the reply mate.

    All fixed. ended up being a problem with my configure.
    I needed to add -qt-mouse-tslib

    Any ideas on how i can incorprate the GPIO's of my BBB with the Qt app?

  • The easiest way to use them is by QProcess. You can run commands like "cat" for reading and "echo" + ">>" to setting values. But this will work just for Linux.

    Another way, to work in more platoforms, you can use QFile and read/write functions to read GPIO file.

    Dont forget to enable kernel and/or buildroot to create gpio files on "/sys/class/gpio", if you are using linux.


  • I had also the same issue, please read the below blog
    This might help you

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