UI does not respond outside ApplicationUI

I'm new developing BlackBerry applications and it's really hard for me understand how it works because the way to develop for BB differs a lot of Android or iOS developing.

Here is my issue: I've created a registerPage.qml and a registerPageController (with it's .hpp and .cpp). I would like the app starts with the registerPage.qml and call form the qml some methods i wrote in the .cpp file.

If I create the qml document outside the ApplicationUI(), the page is displayed nice, but the buttons does not respond.

I think with the code is easily to understand:

applicationui.cpp

ApplicationUI::ApplicationUI() : QObject()
{
    m_pTranslator = new QTranslator(this);
    m_pLocaleHandler = new LocaleHandler(this);

    bool res = QObject::connect(m_pLocaleHandler, SIGNAL(systemLanguageChanged()), this, SLOT(onSystemLanguageChanged()));
    Q_ASSERT(res);
    Q_UNUSED(res);

    onSystemLanguageChanged();

    // --> OPTION 1 (what I want) <--
    /* If I init the register page here, the page is
       displayed ok, but buttons does not respond.
       The RegisterPage initialization code is below. */
    // RegisterPage registerPage;

    // --> OPTION 2 <--
    /* If I create the registerPage here, buttons respond
       but the _register param is not setted properly*/
       QmlDocument *qml = QmlDocument::create("asset:///registerPage.qml").parent(this);
       qml->setContextProperty("_register", this);

       AbstractPane *root = qml->createRootObject<AbstractPane>();
       Application::instance()->setScene(root);
}

registerPage.hpp

class RegisterPage: public QObject
{
    Q_OBJECT
public:
    RegisterPage();
    virtual ~RegisterPage() {}

    Q_INVOKABLE void initRegistration();
};

registerPage.cpp

RegisterPage::RegisterPage()
{
    /* With this initialization, buttons does not respond!!*/
    QmlDocument *qml = QmlDocument::create("asset:///registerPage.qml").parent(this);
    qml->setContextProperty("_register", this);

    // Create root object for the UI
    AbstractPane *root = qml->createRootObject<AbstractPane>();


    // Set created root object as the application scene
    Application::instance()->setScene(root);
}

void RegisterPage::initRegistration()
{
    qDebug() << "start registration!";
}

registerPage.qml

Page {
    Container {
        Button {
            text: "Accept"
            horizontalAlignment: HorizontalAlignment.Fill
            topMargin: 100.0
            appearance: ControlAppearance.Primary
            onClicked: {
                console.log("click!!")
                _register.initRegistration()
            }
        }
    }
}

How can I load an qml file, associate it an .cpp and call functions from qml? Why the buttons does not respond?

Thanks a lot, and sorry if this is the basis of BlackBerry development, but this is making me crazy.

----------------

EDITED

Finally thanks to @Filip Hazubski to help me to find the final solution.

In applicationui.cpp

QmlDocument *qml = QmlDocument::create("asset:///registerPage.qml").parent(this);
AbstractPane *root = qml->createRootObject<AbstractPane>();

RegisterPage* registerPage = new RegisterPage(this, root);
qml->setContextProperty("_register", registerPage);

Application::instance()->setScene(root);

and in registerPage.cpp

RegisterPage::RegisterPage(QObject *parent, AbstractPane *root) : QObject(parent)
{
    phoneTextField = root->findChild<TextField*>("phoneTextField");
}

Passing the AbstractPane as param we can find the qml elements into the registerPage.cpp.

Thanks!

I am not sure but maybe my answer will help you.

In applicationui.cpp instead of:

QmlDocument *qml = QmlDocument::create("asset:///registerPage.qml").parent(this);
qml->setContextProperty("_register", this);

AbstractPane *root = qml->createRootObject<AbstractPane>();
Application::instance()->setScene(root);

try:

QmlDocument *qml = QmlDocument::create("asset:///registerPage.qml").parent(this);
AbstractPane *root = qml->createRootObject<AbstractPane>();

RegisterPage* registerPage = new RegisterPage(this);
qml->setContextProperty("_register", registerPage);

Application::instance()->setScene(root);

and in registerPage.hpp

RegisterPage();

change to

RegisterPage(QObject *parent = 0);

and in registerPage.cpp change

RegisterPage::RegisterPage()
{
    /* With this initialization, buttons does not respond!!*/
    QmlDocument *qml = QmlDocument::create("asset:///registerPage.qml").parent(this);
    qml->setContextProperty("_register", this);

    // Create root object for the UI
    AbstractPane *root = qml->createRootObject<AbstractPane>();


    // Set created root object as the application scene
    Application::instance()->setScene(root);
}

to

RegisterPage::RegisterPage(QObject *parent) : QObject(parent)
{
}