Pass parameters from QML to C++

celica

Hello, I currently have a tumbler built in qml which I can extract the current user set time. I have these 3 parameters (hour, minute, am/pm) printing to the console using this code.

Button 
{text: "Set"
//onClicked: model.submit()
onClicked: print(hoursTumbler.hourcode, minutesTumbler.mincode, amPmTumbler.ampmcode)							 
}

My question is how can I pass these 3 parameters back to my C++ code which houses my main application.
The C++ code currently calls the QML file like this.

QQuickView* quickView = new QQuickView(QUrl::fromLocalFile(QDir::currentPath() + "\\Resources\\videos\\aos.qml"));
		// Make the QML view resize when the parent is resized
		quickView->setResizeMode(QQuickView::SizeRootObjectToView);
		quickWidgettum = new QWidget;
		// Add the QML view to my widget layout
		quickWidgettum = QWidget::createWindowContainer(quickView);
		quickWidgettum->setWindowFlags(Qt::FramelessWindowHint | Qt::Window);
		laos->addWidget(quickWidgettum);
		quickWidgettum->hide();

Bob64

@celica I haven't used QQuickView but from the documentation I would imagine that you do something like this:

MyApi* api = new MyApi(...);

quickView->engine()->setContextProperty("myApi", api);

where

#include <QObject>

class MyApi : public QObject
{
    Q_OBJECT
public:
    ...
    Q_INVOKABLE virtual void setValue(int i);
   ...
};

Then in your QML, the identifier myApi is available to you and you should be able to call e.g. myApi.setValue(10) from javascript code.

celica

Thanks for the input.
I do not have an engine in my code. So I simply use
quickViewdate->rootContext()->setContextProperty("myApi", api);

I get the error ReferenceError: myApi is not defined when I try and call the function to connect.

KroMignon

@celica I think you need to do this is several steps:

QQuickView* quickView = new QQuickView()
quickView->rootContext()->setContextProperty("myApi", api);
quickView->setSource(QUrl::fromLocalFile(QDir::currentPath() + "\\Resources\\videos\\aos.qml")));
// More initialization, if required
..
quickView->show();

celica

@KroMignon Thanks all for your input
I managed to get it working. This may help someone:
What I did was within my qml file created these objectname tags for each tumbler:

Tumbler 
{
id: minutesTumbler
objectName: "min"
model: 60
delegate: delegateComponent
readonly property int mincode: minutesTumbler.currentIndex
}

Then from within c++ ->

QQuickItem* object = quickView->rootObject();
QObject *v_hour = object->findChild<QObject*>("hour");
double myhour = v_hour->property("hourcode").toDouble();
qDebug() << "Tumbler Data: " << myhour;

Pablo J. Rogina

@celica said in Pass parameters from QML to C++:

I managed to get it working

Great. So please don't forget to mark your post as solved!

ODБOï

@celica said in Pass parameters from QML to C++:

double myhour = v_hour->property("hourcode").toDouble();

you can ensure conversion happened correctly if you pass a bool to toDouble
https://doc.qt.io/qt-5/qstring.html#toDouble