Some enums from a C++ namespace have undefined values in QML

Georgi Pashov

I have defined a namespace with enums in C++ to use both in C++ and QML code. Some of the values work fine but others give undefined value.
There are around 30 enums in the namespace. Some have up to around 500 values.
I've defined them all in the same way:

namespace AppEnumsNs
{
    Q_NAMESPACE

    typedef enum EAppGUI_HPsIDs
    {
        APP_GUI_HP1_ID,
        APP_GUI_HP2_ID,
        APP_GUI_HP3_ID,
        APP_GUI_HP4_ID,
        APP_GUI_MAXNUM_HP
    } cAppGUI_HPsIds;    
    Q_ENUM_NS(EAppGUI_HPsIDs)
...
}

I've registered the namespace by qmlRegisterUncreatableMetaObject.

This is the main function:

int main(int argc, char *argv[])
{
    set_qt_environment();
    QGuiApplication app(argc, argv);

    QQmlApplicationEngine engine;
    const QUrl url(u"qrc:Main/main.qml"_qs);
    QObject::connect(
                &engine, &QQmlApplicationEngine::objectCreated, &app,
                [url](QObject *obj, const QUrl &objUrl) {
        if (!obj && url == objUrl)
            QCoreApplication::exit(-1);
    },
    Qt::QueuedConnection);

    engine.addImportPath(QCoreApplication::applicationDirPath() + "/qml");
    engine.addImportPath(":/");

    qmlRegisterUncreatableMetaObject(AppEnumsNs::staticMetaObject, "define.enums", 1, 0, "AppEnumsNs", "Access to enums only");

    CallbackWrapper cbkWpr;
    engine.rootContext()->setContextProperty("cbkWpr", &cbkWpr);

    engine.rootContext()->setContextProperty("wdgWpr", &wdgWpr);

    engine.load(url);

    if (engine.rootObjects().isEmpty()) {
        return -1;
    }

    return app.exec();
}

In the QML files I've imported the module define.enums 1.0
And while some enums work correctly others give undefined values.
Someone knows the reason for the undefined values?

fcarney

When I get undefined it is usually because I misspelled an enum or property.
Does the above code actually reproduce the problem? Can you provide code that reproduces this issue?

Georgi Pashov

@fcarney It's true that the misspelled enums give the same problem but this is not the cause.

I created a simpler project that reproduces the problem. It displays an enum value in a text widget.
I created the project in Qt Design Studio. Generated the CMake Build Files. Opened it in Qt Creator.
Added two files:
src/AppGuiInterfaceStructure.h
src/AppGuiInterfaceStructure.cpp.
Edited files:
src/main.cpp
content/App.qml
content/Screen01.ui.qml

AppGuiInterfaceStructure.h

#ifndef APPGUIINTERFACESTRUCTURE_H_
#define APPGUIINTERFACESTRUCTURE_H_

#include <QObject>

namespace AppEnumsNs
{
    Q_NAMESPACE

    typedef enum EAppGUI_HPsIDs
    {
        APP_GUI_HP1_ID,
        APP_GUI_HP2_ID,
        APP_GUI_HP3_ID,
        APP_GUI_HP4_ID,
        APP_GUI_MAXNUM_HP
    } cAppGUI_HPsIds;
    Q_ENUM_NS(EAppGUI_HPsIDs)

    // Widgets de la Interface
    typedef enum EAppGUIwidgetIDlist
    {

        //PANTALLA DE CARGA
        imgLoadScrBckGnd,
        imgLoadAnim1,
        imgLoadAnim2,
        imgLoadAnim3,
        imgLoadAnim4,
        imgLoadAnim5,
        imgLoadAnim6,
        imgLoadAnim7,
        imgLoadAnim8,

        //PANTALLA DE INICIO
        imgInitScrBckGnd,
        butSelectWoman,
        butSelectMan,
        imgInitGPRScoverage,		//V7790

        //Menu principal
        butInitScrShowMainMenu,
        butInitScrHideMainMenu,
        imgInitScrHome,
        butInitScrCfg,
        butInitScrCalc,
        butInitScrData,

        swInitScrAvisos,
        imgInitScrNotificacion,
        popupInitScrAvisos,
        imgPopUpInitScrAvisoBckGND,
        imgPopUpInitScrAvisoNivelAguaBajo,
        imgPopUpInitScrAvisoNivelAguaMedio,
        imgPopUpInitScrAvisoTempAmb,
        imgPopUpInitScrAvisoRFID,
        imgPopUpInitScrAvisoRTC,
        imgPopUpInitScrAvisoFiltroAire,

        //PANTALLA DE TRATAMIENTO
        imgTrtScrBckGnd,
        imgFullBodyAndZoom,
        imgTrtGPRScoverage,				//V7790

        //Fondos de los paneles de control
        imgCtrlPnlBckGndHP1,
        imgCtrlPnlBckGndHP2,
        imgCtrlPnlBckGndHP3,
        imgCtrlPnlBckGndHP4,

        //Colores fondos de los paneles de control
        imgColourCtrlPnlBckGndHP1,
        imgColourCtrlPnlBckGndHP2,
        imgColourCtrlPnlBckGndHP3,
        imgColourCtrlPnlBckGndHP4,

        //Indicadores de accion del HP cuando activos, los inactivos forman parte del fondo
        imgCtrlPnlRFIDblinkHP1,
        imgCtrlPnlRFIDblinkHP2,
        imgCtrlPnlRFIDblinkHP3,
        imgCtrlPnlRFIDblinkHP4,
        imgCtrlPnlPulBlinkHP1,
        imgCtrlPnlPulBlinkHP2,
        imgCtrlPnlPulBlinkHP3,
        imgCtrlPnlPulBlinkHP4,
        imgCtrlPnlVacBlinkHP1,
        imgCtrlPnlVacBlinkHP2,
        imgCtrlPnlVacBlinkHP3,
        imgCtrlPnlVacBlinkHP4,
        imgCtrlPnlCoolingBlinkHP1,
        imgCtrlPnlCoolingBlinkHP2,
        imgCtrlPnlCoolingBlinkHP3,
        imgCtrlPnlCoolingBlinkHP4,

        //Botones del panel de control de PLAY y Test Vacum
        butCtrlPnlPlayHP1,
        butCtrlPnlPlayHP2,
        butCtrlPnlPlayHP3,
        butCtrlPnlPlayHP4,
        swCtrlPnlTstVacHP1,
        swCtrlPnlTstVacHP2,
        swCtrlPnlTstVacHP3,
        swCtrlPnlTstVacHP4,

        //Botones (switch) que permite seleccionar modo de tratamiento AUTO o MANUAL
        butSwtchModeAutoManualHP1,
        butSwtchModeAutoManualHP2,
        butSwtchModeAutoManualHP3,
        butSwtchModeAutoManualHP4,

        //Visores de tiempo restante de trt y boton de seleccion de tiempo
        numVwrTimeHP1,
        numVwrTimeHP2,
        numVwrTimeHP3,
        numVwrTimeHP4,
        butSelectTimeHP1,
        butSelectTimeHP2,
        butSelectTimeHP3,
        butSelectTimeHP4,
        butVwrTemperatureHP1,
        butVwrTemperatureHP2,
        butVwrTemperatureHP3,
        butVwrTemperatureHP4,

        //Visor numerico para contabilizar resucciones
        numVwrResucctionCountHP1,
        numVwrResucctionCountHP2,
        numVwrResucctionCountHP3,
        numVwrResucctionCountHP4,

        //Boton con la imagen e imagen con el texto del modelo
        imgModelTextHP1,
        imgModelTextHP2,
        imgModelTextHP3,
        imgModelTextHP4,
        butModelImageHP1,
        butModelImageHP2,
        butModelImageHP3,
        butModelImageHP4,

        //Botonoes de recogida y despliegue del panel de control
        butHideControlPanelHP1,
        butHideControlPanelHP2,
        butHideControlPanelHP3,
        butHideControlPanelHP4,
        butShowControlPanelHP1,
        butShowControlPanelHP2,
        butShowControlPanelHP3,
        butShowControlPanelHP4,

        //Botones de selección de Full body
        butFullBodyTorso,
        butFullBodyPiernas,
        butFullBodyBrazos,
        butFullBodyEspalda,
        butFullBodyPiernaMuslo,
        butFullBodyCuello,

        //Puntos seleccion de zona de tratamiento cuando zoom
        swDotZone0,
        swDotZone1,
        swDotZone2,
        swDotZone3,
        swDotZone4,
        swDotZone5,
        swDotZone6,
        swDotZone7,
        swDotZone8,
        swDotZone9,
        swDotZone10,
        swDotZone11,
        swDotZone12,
        swDotZone13,
        swDotZone14,

        //Punto seleccionado para tratamiento con ese HP a mostrar en full body
        imgSelectedTrtZoneHP1,
        imgSelectedTrtZoneHP2,
        imgSelectedTrtZoneHP3,
        imgSelectedTrtZoneHP4,

        //POPUP's
        //Common
        butPopUpReturn,
        imgPopUpHPcolorBar,

        //PopUp Time widgets
        popUpTime,
        butPopUpTime50min,
        butPopUpTime70min,
        imgPopUpTime1sel,
        imgPopUpTime2sel,

        //PopUp Test Vacum widgets
        popUpTstVac,
        imgPopUpTstVacBckGnd,
        imgPopUpTstVacLowLvl,
        imgPopUpTstVacMidLvl,
        imgPopUpTstVacHighLvl,
        imgPopUpTstVacPulHand,
        imgPopUpTstVacPulHandx2,
        butPopUpTstVacManualLowLvl,
        butPopUpTstVacManualMidLvl,
        butPopUpTstVacManualHighLvl,
        butPopUpTstVacAuto,
        swPopUpTstVacLowLvl,
        swPopUpTstVacMidLvl,
        swPopUpTstVacHighLvl,
        imgPopUpTstVacAUTOstatus,

        //PopUp Test Vacuum 2 widgets
        popUpTstVacSmall,
        imgPopUpVacSelBck,
        butPopUpTstVacSmallLowLvl,
        butPopUpTstVacSmallMedLvl,
        butPopUpTstVacSmallHighLvl,

        //PopUp RFID widgets
        popUpRFID,
        imgPopUpRFIDbckGnd,
        imgPopUpRFIDlabel,
        imgPopUpRFIDresult,
        butPopUpRFIDreuseLabel,
        numVwrPopUpRFIDrestTime,

        //PopUp Recommendation widgets
        swPopUpRecommInfo,
        popUpRecomm,
        imgPopUpRecommbckGnd,
        imgPopUpRecommCurved,
        imgPopUpRecommTight,
        imgPopUpRecommStright,
        imgPopUpRecommTiny,
        imgPopUpRecommTinyCurved,
        imgPopUpRecommDouble,
        imgPopUpRecommOval,
        imgPopUpRecommOvalCurved,
        imgPopUpRecommAngled,

        //Menu Principal
        butTrtScrShowMainMenu,
        butTrtScrHideMainMenu,
        butTrtScrHome,
        butTrtScrCfg,
        butTrtScrCalc,
        butTrtScrData,

        swTrtScrAvisos,
        imgTrtScrNotificacion,
        popupTrtScrAvisos,
        imgPopUpTrtScrAvisoBckGND,
        imgPopUpTrtScrAvisoNivelAguaBajo,
        imgPopUpTrtScrAvisoNivelAguaMedio,
        imgPopUpTrtScrAvisoTempAmb,
        imgPopUpTrtScrAvisoRFID,
        imgPopUpTrtScrAvisoRTC,
        imgPopUpTrtScrAvisoFiltroAire,

        //popUp's Error
        imgPopUpErrBckGndHP1,
        imgPopUpErrBckGndHP2,
        imgPopUpErrBckGndHP3,
        imgPopUpErrBckGndHP4,
        imgPopUpErrBckGndUC,
        numVwrPopUpErrHP1,
        numVwrPopUpErrHP2,
        numVwrPopUpErrHP3,
        numVwrPopUpErrHP4,
        numVwrPopUpErrUC,
        imgPopUpErrMsgHP1,
        imgPopUpErrMsgHP2,
        imgPopUpErrMsgHP3,
        imgPopUpErrMsgHP4,
        imgPopUpErrMsgUC,
        butPopUpErrOkHP1,
        butPopUpErrOkHP2,
        butPopUpErrOkHP3,
        butPopUpErrOkHP4,
        butPopUpErrOkUC,
        numVwrPopUpErrTRTtimeHP1,
        numVwrPopUpErrTRTtimeHP2,
        numVwrPopUpErrTRTtimeHP3,
        numVwrPopUpErrTRTtimeHP4,

        //PopUp's CleanUp
        imgPopUpCleanBckGndHP1,
        imgPopUpCleanBckGndHP2,
        imgPopUpCleanBckGndHP3,
        imgPopUpCleanBckGndHP4,
        numVwrPopUpCleanHP1,
        numVwrPopUpCleanHP2,
        numVwrPopUpCleanHP3,
        numVwrPopUpCleanHP4,
        butPopUpCleanHP1,
        butPopUpCleanHP2,
        butPopUpCleanHP3,
        butPopUpCleanHP4,
        butPopUpCleanYESHP1,
        butPopUpCleanYESHP2,
        butPopUpCleanYESHP3,
        butPopUpCleanYESHP4,
        butPopUpCleanNOHP1,
        butPopUpCleanNOHP2,
        butPopUpCleanNOHP3,
        butPopUpCleanNOHP4,
        imgPopUpCleanHP1,
        imgPopUpCleanHP2,
        imgPopUpCleanHP3,
        imgPopUpCleanHP4,
        butPopUpCleanCancelHP1,
        butPopUpCleanCancelHP2,
        butPopUpCleanCancelHP3,
        butPopUpCleanCancelHP4,
        numVwrPopUpCleanNumCancelHP1,
        numVwrPopUpCleanNumCancelHP2,
        numVwrPopUpCleanNumCancelHP3,
        numVwrPopUpCleanNumCancelHP4,


        //Pantalla de la calculadora
        imgFondoCalcScreen,
        imgCuerpoCalc,
        numVwrPantallaCalc,
        butNum0Calc,
        butNum1Calc,
        butNum2Calc,
        butNum3Calc,
        butNum4Calc,
        butNum5Calc,
        butNum6Calc,
        butNum7Calc,
        butNum8Calc,
        butNum9Calc,
        butMasCalc,
        butMenosCalc,
        butEnterCalc,
        butCECalc,
        butComaCalc,

        //Menu principal - calculadora
        butCalcScrShowMainMenu,
        butCalcScrHideMainMenu,
        butCalcScrHome,
        butCalcScrCfg,
        imgCalcScrCalc,
        butCalcScrData,

        swCalcScrAvisos,
        imgCalcScrNotificacion,
        popupCalcScrAvisos,
        imgPopUpCalcScrAvisoBckGND,
        imgPopUpCalcScrAvisoNivelAguaBajo,
        imgPopUpCalcScrAvisoNivelAguaMedio,
        imgPopUpCalcScrAvisoTempAmb,
        imgPopUpCalcScrAvisoRFID,
        imgPopUpCalcScrAvisoRTC,
        imgPopUpCalcScrAvisoFiltroAire,

        //Pantalla de configuración
        imgFondoCfgScreen,
        imgVentanaCfgCastellano,
        butCfgActualizarSoftware,
        imgSoftwareProgressionUpdateBar,
        numVwrModeloMaqCfg,
        numVwrVersionSoftwareCfg,
        butCfgRecargaCoolant,
        swCfgResuctionViewer,
        swCfgTemperatureViewer,
        butCfgCleanUpHP1,
        butCfgCleanUpHP2,
        butCfgCleanUpHP3,
        butCfgCleanUpHP4,
        butCfgCleanUpRoundHP,
        imgCfgGPRScoverage,		//V7790

        //Menu principal - configuracion
        butCfgScrShowMainMenu,
        butCfgScrHideMainMenu,
        butCfgScrHome,
        imgCfgScrCfg,
        butCfgScrCalc,
        butCfgScrData,

        swCfgScrAvisos,
        imgCfgScrNotificacion,
        popupCfgScrAvisos,
        imgPopUpCfgScrAvisoBckGND,
        imgPopUpCfgScrAvisoNivelAguaBajo,
        imgPopUpCfgScrAvisoNivelAguaMedio,
        imgPopUpCfgScrAvisoTempAmb,
        imgPopUpCfgScrAvisoRFID,
        imgPopUpCfgScrAvisoRTC,
        imgPopUpCfgScrAvisoFiltroAire,

        //Pantalla de idiomas
        imgFondoLanScreen,

        swLanFrances,
        swLanCastellano,
        swLanIngles,
        swLanItaliano,
        swLanAleman,
        swLanPolaco,
        swLanRuso,
        swLanPortugues,
        swLanChino,
        swLanJapones,
        swLanCoreano,

        //Menu principal - idiomas
        butLanScrShowMainMenu,
        butLanScrHideMainMenu,
        butLanScrHome,
        butLanScrCfg,
        butLanScrCalc,
        imgLanScrData,

        swLanScrAvisos,
        imgLanScrNotificacion,
        popupLanScrAvisos,
        imgPopUpLanScrAvisoBckGND,
        imgPopUpLanScrAvisoNivelAguaBajo,
        imgPopUpLanScrAvisoNivelAguaMedio,
        imgPopUpLanScrAvisoTempAmb,
        imgPopUpLanScrAvisoRFID,
        imgPopUpLanScrAvisoRTC,
        imgPopUpLanScrAvisoFiltroAire,

        //Pantalla de SAT
        imgFondoSATscreen,
        butHomeSATscreen,

        numVwrPaginaSATscreen,
        butNextPagSATscreen,
        butPrevPagSATscreen,

        imgVwr1,
        imgVwr2,
        imgVwr3,
        imgVwr4,
        imgVwr5,
        imgVwr6,
        imgVwr7,
        imgVwr8,
        imgVwr9,
        imgVwr10_1,
        imgVwr10_2,
        imgVwr11_1,
        imgVwr11_2,
        imgVwr12_1,
        imgVwr12_2,
        imgVwr13_1,
        imgVwr13_2,
        imgVwr14_1,
        imgVwr14_2,
        imgVwr15_1,
        imgVwr15_2,
        imgVwr16_1,
        imgVwr16_2,
        imgVwr17_1,
        imgVwr17_2,
        imgVwr18_1,
        imgVwr18_2,
        imgVwr19_1,
        imgVwr19_2,
        imgVwr20_1,
        imgVwr20_2,
        imgVwr21_1,
        imgVwr21_2,
        imgVwr22_1,
        imgVwr22_2,
        imgVwr23_1,
        imgVwr23_2,
        imgVwr24_1,
        imgVwr24_2,
        imgVwr25_1,
        imgVwr25_2,
        imgVwr26_1,
        imgVwr26_2,
        imgVwr27_1,
        imgVwr27_2,
        imgVwr28_1,
        imgVwr28_2,

        numVwr1,
        numVwr2,
        numVwr3,
        numVwr4,
        numVwr5,
        numVwr6,
        numVwr7,
        numVwr8,
        numVwr9,
        numVwr10,
        numVwr11,
        numVwr12,
        numVwr13,
        numVwr14,
        numVwr15,
        numVwr16,
        numVwr17,
        numVwr18,
        numVwr19,
        numVwr20,
        numVwr21,
        numVwr22,
        numVwr23,
        numVwr24,
        numVwr25,
        numVwr26,
        numVwr27,
        numVwr28,

        imgVacuum,
        imgFrio,
        imgRFID,
        imgTestLed,
        imgTestLedStatus,
        imgTestLedRGD,
        swVacuum,
        swFrio,
        swRFID,
        swTestLed,
        swTestLedRGB,

        PopupErrorSAT,
        imgVwrFondoErrorSAT,
        numVwrError1,
        numVwrError2,
        numVwrError3,
        numVwrError4,
        numVwrError5,
        butOkerr,

        //Pantalla de FATIGA
        imgFondoFATIGAscreen,
        butHomeFATIGAscreen,

        imgStep1,
        imgStep1status,
        imgStep2,
        imgStep2status,
        imgStep3,
        imgStep3status,
        imgStep4,
        imgStep4statusHP1,
        imgStep4statusHP2,
        imgStep4statusHP3,
        imgStep4statusHP4,
        imgStep5,
        imgStep5statusHP1,
        imgStep5statusHP2,
        imgStep5statusHP3,
        imgStep5statusHP4,
        imgStep6,
        imgStep6status,
        imgStep7,
        imgStep7status,

        numVwrTempAmb,
        numVwrTempBomba,
        numVwrTempRetorno,
        numVwrCaudalRetorno,
        numVwrVtobera,
        numVwrRth,
        numVwrCPI,
        numVwrCaudalRetornoHP1,
        numVwrCaudalRetornoHP2,
        numVwrCaudalRetornoHP3,
        numVwrCaudalRetornoHP4,
        numVwrVacuumHP1,
        numVwrVacuumHP2,
        numVwrVacuumHP3,
        numVwrVacuumHP4,
        numVwrFatigaTime,
        numVwrErrFatiga1,
        numVwrErrFatiga2,
        numVwrErrFatiga3,
        numVwrErrFatiga4,
        numVwrErrFatiga5,

        imgVwrVAC1,
        imgVwrVAC2,
        imgVwrVAC3,
        imgVwrVAC4,
        imgVwrCaudal1,
        imgVwrCaudal2,
        imgVwrCaudal3,
        imgVwrCaudal4,
        imgVwrTempAmb,
        imgVwrTempBomba,
        imgVwrTempRetorno,
        imgVwrCaudalRetorno,
        imgVwrVtobera,
        imgVwrRth,
        imgVwrCPI,				//447

        swFatigueFailBeep,

        APP_GUI_NUM_WIDGETS
    }cAppGUIwidgetIDlist;
    Q_ENUM_NS(EAppGUIwidgetIDlist)
}

using namespace AppEnumsNs;


#endif /* APPGUIINTERFACESTRUCTURE_H_ */

AppGuiInterfaceStructure.cpp

/*Includes*/
#include "AppGuiInterfaceStructure.h"

main.cpp

#include <QGuiApplication>
#include <QQmlApplicationEngine>
#include <QQmlEngine>

#include "app_environment.h"
#include "import_qml_plugins.h"
#include "AppGUI/AppGuiInterfaceStructure.h"

int main(int argc, char *argv[])
{
    set_qt_environment();
    QGuiApplication app(argc, argv);

    QQmlApplicationEngine engine;
    const QUrl url(u"qrc:Main/main.qml"_qs);
    QObject::connect(
                &engine, &QQmlApplicationEngine::objectCreated, &app,
                [url](QObject *obj, const QUrl &objUrl) {
        if (!obj && url == objUrl)
            QCoreApplication::exit(-1);
    },
    Qt::QueuedConnection);

    engine.addImportPath(QCoreApplication::applicationDirPath() + "/qml");
    engine.addImportPath(":/");

    qmlRegisterUncreatableMetaObject(AppEnumsNs::staticMetaObject, "define.enums", 1, 0, "AppEnumsNs", "Access to enums only");

    engine.load(url);

    if (engine.rootObjects().isEmpty()) {
        return -1;
    }

    return app.exec();
}

App.qml

import QtQuick
import QtQuick.Window
import EnumsProblem
import define.enums 1.0

Window {
    width: mainScreen.width
    height: mainScreen.height

    visible: true
    title: "EnumsProblem"

    Screen01 {
        id: mainScreen
        button.onReleased: text1Text = AppEnumsNs.imgLoadAnim6
    }
}

Screen01.ui.qml

import QtQuick
import QtQuick.Controls
import EnumsProblem

Rectangle {
    width: Constants.width
    height: Constants.height

    color: Constants.backgroundColor
    property alias text1Text: text1.text
    property alias button: button

    Text {
        id: text1
        width: 196
        height: 102
        text: qsTr("Hello EnumsProblem")
        horizontalAlignment: Text.AlignHCenter
        verticalAlignment: Text.AlignVCenter
        font.pointSize: 35
        anchors.centerIn: parent
        font.family: Constants.font.family
    }

    Button {
        id: button
        x: 478
        y: 467
        text: qsTr("Button")
    }
}

When I'm assigning value from the first enum, e.g. AppEnumsNs.APP_GUI_MAXNUM_HP, it works fine and the value is displayed.
If it's from the second, e.g. AppEnumsNs.imgLoadAnim6, I get an error during execution: Error: Cannot assign [undefined] to QString

fcarney

TypeError: Cannot access enum value 'imgLoadAnim6' of 'AppEnumsNs', enum values need to start with an uppercase letter.

Next time you post code make sure it is runnable:

Create a new test project.
Add code to project until you can reproduce the issue.
Make sure it can run.
Then post that project.

Posting stuff from existing projects makes it harder to help you.

Test in 5.15.2 btw.

Georgi Pashov

@fcarney Thanks a million. That was the problem.
And thanks for the advice.

Solved Some enums from a C++ namespace have undefined values in QML