Native Development

[gdev001]

Hi, again I am trying to run  a sample from BlackBerry web site. This time this one:

"Injecting C++ objects into QML" (the last section on the bottom) - from page:

https://developer.blackberry.com/cascades/documentation/dev/integrating_cpp_qml/index.html,

This is my code:

cpp file

#include "CombineCppAndQml.hpp"

#include <bb/cascades/Application>
#include <bb/cascades/QmlDocument>
#include <bb/cascades/AbstractPane>

#include <bb/cascades/Color>
#include <bb/cascades/Container>
#include <bb/cascades/DockLayout>
#include <bb/cascades/ImageView>
#include <bb/cascades/Page>
#include <bb/cascades/Slider>
#include <bb/cascades/Stacklayout>
#include <bb/cascades/StackLayoutProperties>

using namespace bb::cascades;

CombineCppAndQml::CombineCppAndQml(bb::cascades::Application *app)
: QObject(app)
{
    QmlDocument *qml = QmlDocument::create("asset:///main.qml").parent(this);
    qml->setContextProperty("injection", this);
    AbstractPane *root = qml->createRootObject<AbstractPane>();
    app->setScene(root);
}

void CombineCppAndQml::injectContainer()
{
    // Creates the container and adds it to the root
    // container in qml
    mRootContainer->add(Container::create()
        .background(Color::Red)
        .preferredSize(200,200)
        .bottomMargin(20)
        .horizontal(HorizontalAlignment::Center));
}

 hpp file

#ifndef CombineCppAndQml_HPP_
#define CombineCppAndQml_HPP_

#include <QObject>

 #include <bb/cascades/Container>
#include <bb/cascades/Page>

namespace bb { namespace cascades { class Application; }}

using namespace bb::cascades;


class CombineCppAndQml : public QObject
{
    Q_OBJECT
public:
    CombineCppAndQml(bb::cascades::Application *app);
    virtual ~CombineCppAndQml() {}

    // By using Q_INVOKABLE we can call it from qml
    Q_INVOKABLE void injectContainer();

private:
    Page *appPage;
    Container *mRootContainer;
};

#endif /* Test_Hpp_ */

 and the qml file as listed on the Web Site.

import bb.cascades 1.0
  
Page {
    // Allows the user to scroll vertically
    ScrollView {
        scrollViewProperties {
            scrollMode: ScrollMode.Vertical
        }
        // Root container that containers from C++ are added to
        Container {
            objectName: "rootContainer"      
            layout: StackLayout {}
            // Button that calls the C++ function to add a
            // new container. The selectedIndex from the drop down
            // is passed to C++.
            Button {
                text: "Add container"
                onClicked: {
                    injection.injectContainer();       
                }
            }
        }
    }
}

 When I run it, I actually see the button, but when I click it in order to open up the second container, my application gets minimized instead of showing the second container.

pps. I also have a separate main.cpp class which calls the CombineCppAndQml class.

Any help greatly appreciated.

[dishooom · Accepted solution]

Please add the following line to your CombineCppAndQml constructor

 mRootContainer = root->findChild<Container*>("rootContainer");

CombineCppAndQml::CombineCppAndQml(bb::cascades::Application *app)
: QObject(app)
{
    QmlDocument *qml = QmlDocument::create("asset:///main.qml").parent(this);
    qml->setContextProperty("injection", this);
    AbstractPane *root = qml->createRootObject<AbstractPane>();
    app->setScene(root);

    mRootContainer = root->findChild<Container*>("rootContainer");
}

 -Dishooom

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Hope this helps

[gdev001]

Thanks. good catch!! I was also thinking smth was wrong with the mRootContainer. Thanks. It is weird how these samples are arranged on the web site, I just copied the code from the site, and that line was not there (it was separately mentioned somewhere else though). ps. Maybe you could also have a look at my other issue? http://supportforums.blackberry.com/t5/Native-Development/Using-C-classes-in-QML/td-p/2133641 thanks again

[dishooom]

I believe that's solved as well ...