I am pretty sure you need to register it to the qmlEngine via

qmlRegisterType<NotchedRectangle>("My.Items", 1, 0, "NotchedRectangle");

In your main.cpp, then you should be able to use it. (https://www.qt.io/blog/qml-type-registration-in-qt-5.15)

In your qml file you can then just type:

import My.Items

and then you should be able to use NotchedRectangle

Yes, you can put any QObject-subclass in as a property (use pointers). Also works with Q_GADGETs.

They both seem like dead projects, nothing you can rely on.

grassator/react-qml last commit was Dec 15, 2017
only 1 contributor, only active 4 years ago.

ongseespace/react-qml last commit was Mar 26, 2020
had 2 contributors, most active 3-4 years ago.

As you may sensed for the extremely few amount of responses before and considering that ReactJS is since many many years one the most prominent JavaScript library in the world, mostly top 1 (https://2021.stateofjs.com/en-US/libraries/front-end-frameworks). It looks not to be in the priority of the Qt strategy.

Looking at the architecture of Qt, they seem pretty much incompatible. Qt is a complete stack with a complete e2e experience. Where you don't want to mix other stacks or other frameworks.

That also means, I think, you cannot for example create QML based components that are reusable in other frontend stacks, where the backend may be anything else. QML are closed components.

So, in other words no support for Web Components specification: https://www.webcomponents.org/introduction
which was created to be able to produce reusable components.

If anybody, disagrees or have more insights, happy to know about it :)

@sierdzio

Ok now it's much clearer, thank you again.

It looks like there is a lot of documentation to read, but apparently most things I have in mind should work. Still, for some reason, I feel QWidgets will perform faster. I'll try to make some tests and get back here.

Thank you again!

@J-Hilk
Ok that's enough I think.

One more question what will happen to scrolleft().

If I keep on incrementing these, will there be any increase in runtime memory or processor load?

@J-Hilk

I got it to work with ifw as well. However, the option --plugindir apparently does not work correctly. The plugins were stored in the folder of the exe.

However, also the installation using ifw was finally successful.

The only solution I found is with inheriting from QStringListModel.

main.cpp

#include <QGuiApplication> #include <QQmlApplicationEngine> #include <QQmlContext> #include <QSettings> #include "MyStringListModel.h" #include <QDebug> int main(int argc, char *argv[]) { QCoreApplication::setAttribute(Qt::AA_EnableHighDpiScaling); QGuiApplication app(argc, argv); QQmlApplicationEngine engine; const QUrl url(QStringLiteral("qrc:/main.qml")); QObject::connect(&engine, &QQmlApplicationEngine::objectCreated, &app, [url](QObject *obj, const QUrl &objUrl) { if (!obj && url == objUrl) QCoreApplication::exit(-1); }, Qt::QueuedConnection); qmlRegisterType <MyStringListModel> ( "StringListModel", 1, 0, "MyStringListModel" ); MyStringListModel lstModel; QSettings settings ( "TestQml.ini", QSettings::IniFormat ); lstModel.readSettings(&settings, "Components"); if ( lstModel.stringList().size() < 1 ) { lstModel.setStringList( QStringList() << "Test 1" << "Test 2"); lstModel.setCurrentIndex(0); } qDebug() << lstModel.stringList(); engine.rootContext()->setContextProperty ("myLstModel", &lstModel ); engine.load(url); return app.exec(); }

MyStringListModel.h

#ifndef MYSTRINGLISTMODEL_H #define MYSTRINGLISTMODEL_H #include <QObject> #include <QStringListModel> class QSettings; class MyStringListModel : public QStringListModel { Q_OBJECT Q_PROPERTY (int CurrentIndex READ getCurrentIndex WRITE setCurrentIndex NOTIFY sigCurrentIndex ) int CurrentIndex; public: MyStringListModel(); int getCurrentIndex () const; void setCurrentIndex ( int indx ); void readSettings ( QSettings *settings, const QString & category ); void writeSettings ( QSettings *settings, const QString & category ) const; public slots: void addNewText ( QString editText ); void sltEditText ( QString editText ); signals: void sigCurrentIndex(); }; #endif // MYSTRINGLISTMODEL_H

MyStringListModel.cpp

#include "MyStringListModel.h" #include <QSettings> MyStringListModel::MyStringListModel() : CurrentIndex ( 0 ) { } int MyStringListModel::getCurrentIndex() const { return CurrentIndex; } void MyStringListModel::setCurrentIndex(int indx) { CurrentIndex = indx; } void MyStringListModel::addNewText(QString editText) { const QStringList &lst = stringList(); for ( int i = 0; i < lst.size(); ++i ) { if ( editText == lst[i] ) return; } setStringList ( stringList() << editText ); setCurrentIndex ( rowCount() - 1 ); } void MyStringListModel::readSettings(QSettings *settings, const QString &category) { settings->beginGroup(category); QStringList lst = settings->value("Entries", QStringList()).toStringList(); setStringList ( lst ); int currentIndex = settings->value("CurrentPosition", 0 ).toInt(); setCurrentIndex(currentIndex); settings->endGroup(); } void MyStringListModel::writeSettings(QSettings *settings, const QString &category) const { settings->beginGroup(category); settings->setValue("Entries", stringList()); settings->setValue("CurrentPosition", CurrentIndex ); settings->endGroup(); } void MyStringListModel::sltEditText(QString editText) { addNewText ( editText ); QSettings settings ( "TestQml.ini", QSettings::IniFormat ); writeSettings(&settings, "Components"); }

main.qml

import QtQuick 2.15 import QtQuick.Controls 2.15 import StringListModel 1.0 ApplicationWindow { width: 640 height: 480 visible: true title: qsTr("Scroll") Frame { ComboBox { id: secondComboBox editable: true model: myLstModel currentIndex: model.CurrentIndex textRole: "display" onAccepted: { if (find(editText) === -1) model.addNewText ( editText ) } } } }