【Error:qt.bluetooth: Dummy backend running】with Running Bluetooth Examples



  • Qt5 version : 5.8.0
    System : Ubuntu 16.04
    bluetooth version : 5.37

    I am starting to do some work with QBluetooth, and find an example "Bluetooth Scanner Example", run it on ubuntu 16.04 .
    Then the error is :
    qt.bluetooth: Dummy backend running ; Qt Bluetooth module is non-functional


  • Moderators

    @Alex_wang Try to start the app with QT_DEBUG_PLUGINS environment variable set:

    QT_DEBUG_PLUGINS=1 && ./my_app
    

    Then post the output. Most probably Bluez library is not installed on your machine.



  • hi,
    I try to run the app with

    QT_DEBUG_PLUGINS=1 && ./my_app
    

    print is :

    Unable to query physical screen size, defaulting to 100 dpi.
    To override, set QT_QPA_EGLFS_PHYSICAL_WIDTH and QT_QPA_EGLFS_PHYSICAL_HEIGHT (in millimeters).
    qt.bluetooth: Dummy backend running. Qt Bluetooth module is non-functional.
    

    And the bluez has been installed, I can use hciconfig hcitool to scan the devices.


  • Moderators

    @Alex_wang You should have much more output when starting with QT_DEBUG_PLUGINS set.


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