[Solved] Receiving signals from QML to C++

spode

thank you a lot. it is 0k! =)

spode

this time, why can not i call leggimi()?
@ #include <QtGui/QApplication>
#include "qmlapplicationviewer.h"
#include "funzioni.h"
#include <QDeclarativeContext>
#include <QGraphicsObject>

int main(int argc, char *argv[])
{
QApplication app(argc, argv);

QmlApplicationViewer viewer;
viewer.setOrientation(QmlApplicationViewer::ScreenOrientationAuto);
viewer.setMainQmlFile&#40;QLatin1String("qml/fileTrenner2/main.qml"&#41;&#41;;
viewer.showExpanded();
viewer.setWindowTitle("File Trenner");
viewer.move(600,20);

Funzioni funz;
QDeclarativeView view(QUrl::fromLocalFile&#40;"qml/fileTrenner2/main.qml"&#41;&#41;;
view.rootContext()->setContextProperty("myObject", &funz);

return app.exec&#40;&#41;;

}
@

@ //funzioni.cpp
#include "funzioni.h"

Funzioni::Funzioni()
{

}

void Funzioni::leggimi()
{
QDeclarativeView view(QUrl::fromLocalFile("qml/fileTrenner2/messaggioLeggimi.qml"));
view.show();
}
@

@ //funzioni.h
#ifndef FUNZIONI_H
#define FUNZIONI_H
#include <QObject>
#include <QDeclarativeView>
#include <QDeclarativeContext>

class Funzioni : public QObject
{
Q_OBJECT

public:
Funzioni();
int caratteriAriga;

public slots:
void leggimi();

};

#endif // FUNZIONI_H
@

i proved to call leggimi in main.qml by using "Image { width: 100; height: 101 MouseArea { anchors.fill:parent; onClicked: myObject.leggimi() } }". error: qml/fileTrenner2/main.qml:416: ReferenceError: Can't find variable: myObject. whY?

lgeyer

I see two problems here.

At first, your QML file is processed before the context property is added.
@
QDeclarativeView view(QUrl::fromLocalFile("qml/fileTrenner2/main.qml"));
view.rootContext()->setContextProperty("myObject", &funz);
@ should probably read
@
QDeclarativeView view;
view.rootContext()->setContextProperty("myObject", &funz);
view.setSource(QUrl::fromLocalFile("qml/fileTrenner2/main.qml"));
@
At second, you add the context property to the root context of view (the QDeclarativeView) and not viewer (the QmlApplicationViewer, which is in fact just a wrapper around another QDeclarativeView). view is actually never shown, the corresponding code can be removed completely.

spode

bq. QDeclarativeView view;
view.rootContext()->setContextProperty("myObject", &funz);
view.setSource(QUrl::fromLocalFile("qml/fileTrenner2/main.qml"));

thank you. you were very clear, but i do not understand why do you declare the QDeclarativeView making save to explain immediatly the file toward which methods will be applied. i mean: where is the conceptual or tecnical difference between the two snippets?

i will use the QDeclarativeView.

loladiro

The qml is being processed as soon as you call setSource (whether directly or indirectly through the constructor). From the documentation:
[quote]
source : QUrl
This property holds the URL of the source of the QML component.
Changing this property causes the QML component to be reloaded.
[/quote]
Therefore, you have to add any special object and context variables before you use setSource. Otherwise they will not be present when (re)loading the qml. Does that make sense to you now?

spode

this is an excellent answer! ;)

spode

ideas for closing the program?

lgeyer

If you want to close your program from QML use Qt.quit().

spode

error: Signal QDeclarativeEngine::quit() emitted, but no receivers connected to handle it.

lgeyer

You have to connect the QDeclarativeEngine::quit() signal to the QApplication::quit() slot.
@
connect(view->engine(), SIGNAL(quit()), QCoreApplication::instance(), SLOT(quit()));
@

Don't forget to add "[Solved]" to topic titles which have been solved for you.

sfilippidis

[OFFTOPIC]
I would kindly like to propose to change the word "Reciving" in the title of the thread to "Receiving". :-)
[/OFFTOPIC]

spode

so, that was made!
how to choose the solver in this thread?

lgeyer

[quote author="spode" date="1308387674"]so, that was made!
how to choose the solver in this thread?[/quote]

Um... what?

If the question is related to this [quote author="Lukas Geyer" date="1308340073"]Don't forget to add "[Solved]" to topic titles which have been solved for you.[/quote] just click the edit button on your first post an change the title from "Receiving signals from QML to C++" to "[Solved] Receiving signals from QML to C++".