Is it possible to setContextProperty local to a qml file displayed in a QQuickWidget??

Gbhutra

I have an app with QMdiArea as the central widget and each QMdiSubWindow has a QQuickWidget which displays a qml item. I have another QObject which gets initialized in each QQuickWidget whoose signals I want to capture in the Qml as shown. I was able to do that by creating a separate instance of QQmlEngine which creates a new QQmlContext my question is that is that the right way? Is it possible to set a context property to a local file?

// SubWindow.cpp 
...
 // class SubWindow : public QMdiSubWindow
SubWindow::SubWindow(QObject* parent, QQmlEngine* engine) : QMdiSubWindow(parent) {
  // creating a new engine as I need separate 'interface' property for each subwindow
  QQmlEngine* newContentEngine = new QQmlEngine(this);
  if (newContentEngine->rootContext() && engine && engine->rootContext()) {
   // copy 'colors' from the parent engine
    newContentEngine->rootContext()->setContextProperty(
        "colors", engine->rootContext()->contextProperty("colors"));
    Content* cont = new Content(this, newContentEngine);
    setWidget(cont);
  }
}
...

// ContentInterface.h
...
class ContentInterface : public QObject {
Q_OBJECT

public:
 ContentInterface(QObject* parent);

public signals:
 void dataChanged();
}
...

// Content.cpp
...
 // class Content : public QQuickWidget
Content::Content(SubWindow* parent, QQmlEngine* contentEngine)  : QQuickWidget(contentEngine, parent) {
  ContentInterface* interface_ = new ContentInterface(this);

  // the rootContext is local to the new Engine created so works! 
  rootContext()->setContextProperty("interface", interface_);
  
  setResizeMode(QQuickWidget::SizeRootObjectToView);
  setSource(QUrl("qrc:/Content.qml"));
}
...

// Content.qml
Rectangle {

Connections  {
  target: interface
  onDataChanged : {
    ...
  }
}

raven-worx

@Gbhutra said in Is it possible to setContextProperty local to a qml file displayed in a QQuickWidget??:

Is it possible to set a context property to a local file?

try QQmlComponent::create() with a newly created QQmlContext instance on which you have set the context property

QQmlComponent comp(engine);
comp.loadUrl(QUrl("qrc:/MyComp.qml"));
QQmlContext* context = new QQmlContext(engine);
context->setContextProperty(...);
QObject* obj = comp.create(context);
context->setParent(obj); // Note: not 100% sure if thats correct, but otherwise context would leak the memory

Gbhutra

Thanks for the response.

How can I embed a QQmlComponenet into a widget/QMdiSubWindow?

Pradeep P N

Hi @Gbhutra
Can you have look at Integrating QML Code with Existing Qt UI Code

Good luck.

raven-worx

@Gbhutra said in Is it possible to setContextProperty local to a qml file displayed in a QQuickWidget??:

How can I embed a QQmlComponenet into a widget/QMdiSubWindow?

QQuickWidget* w = new QQuickWIdget( engine ); // use the same shared engine instance
w->setResizeMode( QQuickWidget::SizeRootObjectToView );
w->setSource("qrc:/MyContainer.qml"); // where the MyContainer comp is a simple plain Item {}
QQuickItem* root = w->rootObject();
QQuickItem* item = qobject_cast<QQuickItem*>(obj); // obj comes from the code of my previous post (the object created from the QQmlComponent)
item->setParentItem( root );
QObject::connect(root, &QQuickItem::widthChanged, item, &QQuickItem::setWidth );
QObject::connect(root, &QQuickItem::heightChanged, item, &QQuickItem::setHeight );

@Pradeep-P-N said in Is it possible to setContextProperty local to a qml file displayed in a QQuickWidget??:

Can you have look at Integrating QML Code with Existing Qt UI Code

this link is related to QML1/Qt4, so not applicable