[Interest] QML MenuBar : works with PySide2 but not c++ ?
Juergen Bocklage-Ryannel
juergen at ryannel.org
Fri Jun 4 17:11:27 CEST 2021
Hi,
My 2 cents: I might not a good idea to name the document “MenuBar.qml" and use a “MenuBar" component inside. Not sure but could give naming conflicts, if the MenuBar component is resolved to the local “MenuBar.qml" document.
So rename your MenuBar.qml to Main.qml, update the code and try again.
Why not in python? I expect the local file url changes the lookup behaviour.
/ jryannel
https://apigear.io
> On 4. Jun 2021, at 16:59, Jérôme Godbout <godboutj at amotus.ca> wrote:
>
> The resources usage seem to be right (added to .pro properly and the name and path seem to match) and the case are correct (assuming the actual file has the same cases). The Qml module must be added like stated below but you might want to also add core and quick control2:
> QT += core qml quick quickcontrols2
>
> You might want to add a trace before exiting -1 into your main.cpp:
> QDebug() << “Failed to load the main qml script”;
> QCoreApplication::exit(-1);
>
> Also check the application output for any error or the Qml output into Qt creator (if you use it) it might tell you it miss some plugins or cannot find something. Maybe you Qml as an error or cannot find a component, it will simply not load making the application return -1 above.
>
>
>
> From: Interest <interest-bounces at qt-project.org> on behalf of Frank Mertens <frank at cyblogic.de>
> Date: Friday, June 4, 2021 at 6:02 AM
> To: interest at qt-project.org <interest at qt-project.org>
> Subject: Re: [Interest] QML MenuBar : works with PySide2 but not c++ ?
>
> No, only QML components need to be uppercase. The C++ and Python code looks 100% the same. The only difference is that the C++ code uses qrc. Must be a bug!-) This is Qt 5.15.
>
> On 03.06.21 15:19, Jason H wrote:
> Why? QML elements are capitalized. They must be.
> the only exception is js imports: import "app.js" as App
>
>
>
> Sent: Thursday, June 03, 2021 at 4:10 AM
> From: "Frank Mertens" <frank at cyblogic.de> <mailto:frank at cyblogic.de>
> To: interest at qt-project.org <mailto:interest at qt-project.org>
> Subject: Re: [Interest] QML MenuBar : works with PySide2 but not c++ ?
> Try a lowercase file name, e.g.: "qrc:/menuBar.qml".
>
> ;)
>
> On 03.06.21 06:08, Nicholas Yue wrote:
> I copied the qml loading code from another working example, I was just testing a change in the QML content.
>
> I'd have to dig further about the lambda
>
> MenuBar.pro
> ===========
> QT += quick
>
> CONFIG += c++11
>
> # The following define makes your compiler emit warnings if you use
> # any Qt feature that has been marked deprecated (the exact warnings
> # depend on your compiler). Refer to the documentation for the
> # deprecated API to know how to port your code away from it.
> DEFINES += QT_DEPRECATED_WARNINGS
>
> # You can also make your code fail to compile if it uses deprecated APIs.
> # In order to do so, uncomment the following line.
> # You can also select to disable deprecated APIs only up to a certain version of Qt.
> #DEFINES += QT_DISABLE_DEPRECATED_BEFORE=0x060000 # disables all the APIs deprecated before Qt 6.0.0
>
> SOURCES += \
> main.cpp
>
> RESOURCES += main.qrc
>
> # Additional import path used to resolve QML modules in Qt Creator's code model
> QML_IMPORT_PATH =
>
> # Additional import path used to resolve QML modules just for Qt Quick Designer
> QML_DESIGNER_IMPORT_PATH =
>
> # Default rules for deployment.
> qnx: target.path = /tmp/$${TARGET}/bin
> else: unix:!android: target.path = /opt/$${TARGET}/bin
> !isEmpty(target.path): INSTALLS += target
>
> main.qrc
> =======
> <RCC>
> <qresource prefix="/">
> <file>MenuBar.qml</file>
> </qresource>
> </RCC>
>
>
> On Wed, 2 Jun 2021 at 20:36, Tony Rietwyk <tony at rightsoft.com.au <mailto:tony at rightsoft.com.au>> wrote:
> Hi Nicholas,
>
> The short answer is because your C++ is doing completely different things to the python code. :O)
>
> I'm not sure about using QML. Have you included the qml file as a resource correctly to access via qrc:? You aren't checking the result of the engine.load. Also, why is the lambda exiting the application when the objectCreated matches the url?
>
> Have run the Qt QML examples? How is your C++ code different to those?
>
> Hope that helps, Tony
>
>
>
> On 3/06/2021 11:33 am, Nicholas Yue wrote:
> Hi,
>
> I am learning about QML.
>
> I would like to find out why the PySide2 loading of the QML file results in a visible window but the C++ one does not. The compiled application runs but no window is displayed.
>
> MenuBar.qml
> ===========
> import QtQuick 2.4
> import QtQuick.Controls 2.13
>
> ApplicationWindow {
> visible: true
> width: 720
> height: 480
> title: "simple window"
>
> menuBar: MenuBar{
> Menu{
> title: "Menu1"
> }
>
> Menu{
> title: "Menu2"
> }
>
> Menu{
> title: "&Menu3"
> }
> }
> }
>
> main.cpp
> ========
> #include <QGuiApplication>
> #include <QQmlApplicationEngine>
>
> int main(int argc, char *argv[])
> {
> QCoreApplication::setAttribute(Qt::AA_EnableHighDpiScaling);
>
> QGuiApplication app(argc, argv);
>
> QQmlApplicationEngine engine;
> const QUrl url(QStringLiteral("qrc:/MenuBar.qml"));
> QObject::connect(&engine, &QQmlApplicationEngine::objectCreated,
> &app, [url](QObject *obj, const QUrl &objUrl) {
> if (!obj && url == objUrl)
> QCoreApplication::exit(-1);
> }, Qt::QueuedConnection);
> engine.load(url);
>
> return app.exec();
> }
>
> main.py
> =======
> import sys
> from PySide2 import QtCore, QtGui, QtQml
>
> if __name__ == '__main__':
>
> QtCore.QCoreApplication.setAttribute(QtCore.Qt.AA_EnableHighDpiScaling)
> app = QtGui.QGuiApplication(sys.argv)
>
> engine = QtQml.QQmlApplicationEngine()
>
> url = QtCore.QUrl.fromLocalFile('MenuBar.qml')
> engine.load(url)
> if not engine.rootObjects():
> sys.exit(-1)
>
> sys.exit(app.exec_())
>
> --
> Nicholas Yue
> Graphics - Arnold, Alembic, RenderMan, OpenGL, HDF5
> Custom Dev - C++ porting, OSX, Linux, Windows
> http://au.linkedin.com/in/nicholasyue <http://au.linkedin.com/in/nicholasyue>
> https://vimeo.com/channels/naiadtools <https://vimeo.com/channels/naiadtools>
>
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>
> --
> Nicholas Yue
> Graphics - Arnold, Alembic, RenderMan, OpenGL, HDF5
> Custom Dev - C++ porting, OSX, Linux, Windows
> http://au.linkedin.com/in/nicholasyue <http://au.linkedin.com/in/nicholasyue>
> https://vimeo.com/channels/naiadtools <https://vimeo.com/channels/naiadtools>
>
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