Make QQuickWidget responsive to resizing

[rithvikp]

I have a MainWindow derived from QMainWindow and two widgets: one QQuickWidget that is showing content from a qml file and one QPrintPreviewWidget. I want to arrange them in such a way that both of them resize to fit the window when the window is expanded and I am unable to do that. When the window pops up, the two widgets are overlapping and when i keep increasing the size of the window, they keep increasing only upto a point after which only the layout expands but the widgets don't expand anymore. Can someone point out what's missing? Here's my code:

main.cpp

#include <QtWidgets>
#include <QtQuickWidgets/QQuickWidget>
#include "preview.h"

class QmlWidget : public QWidget
{
public:
    QmlWidget() {
        qml_widget = new QQuickWidget(QUrl("qrc:/main.qml"), this);
        qml_widget->setResizeMode(QQuickWidget::SizeRootObjectToView);
    }
private:
    QQuickWidget *qml_widget;
};

class MainWindow : public QMainWindow
{
public:
    MainWindow() {
        QHBoxLayout *layout = new QHBoxLayout();

        QmlWidget *qml_widget =  new QmlWidget();
        qml_widget->resize(640,480);

        PrintPreviewWidget *preview_widget =  new PrintPreviewWidget();
        preview_widget->resize(360,480);

        layout->addWidget(qml_widget);
        layout->addWidget(preview_widget);

        setCentralWidget(new QWidget());
        centralWidget()->setLayout(layout);
    }
};

int main(int argc, char** argv)
{
    QApplication app(argc, argv);
    MainWindow window;
    window.show();
    return app.exec();
}

main.qml

Rectangle {
    visible: true
    width: 640
    height: 480
}

[jiancaiyang]

Difficult to anwser...
But you may notice the size policy first.