How to alter the properties of qml using Cpp.

[Guest]

Below I have written my code, I would like to change the child property of "rect" for ex. the color of the child rectangle. If i give the change in main.qml only the parent object is changed the child rectangle remains unchanged... Kindly help me pleaseeeee

[Guest]

MyItem.qml

@
Rectangle

{

 width: 400; height:400
 color:"white"
 property string i:"asdff"
 property int j:25
 property int u:0

 signal clicked()





 Rectangle {
     id:rect2

     objectName: rect;
     anchors.top: parent.top
     anchors.topMargin: 45
     anchors.left: parent.left
     anchors.leftMargin: 35
     anchors.right: parent.right
     anchors.rightMargin: 50
     height: 30
     radius: 8
     color:"grey"

}}
@

[Edit: Added @ tags and deleted duplicate post. You can edit previous posts rather than reposting. -- mlong]

[Guest]

Main.cpp

@#include <QtCore/QCoreApplication>
#include <QtGui/QApplication>
#include <QDeclarativeView>
#include <QDeclarativeProperty>
#include <QGraphicsObject>
#include <QObject>
#include "MyClass.h"
#include <QDebug>
#include <QDeclarativeContext>

int main(int argc, char *argv[]) {
QApplication app(argc, argv);
QDeclarativeView view;
view.setSource(QUrl::fromLocalFile("Test.qml";);
QObject *object1 = view.rootObject();

/// insert code here//
MyClass myClass;
view.rootContext()->setContextProperty("object", &myClass);
view.show();
return app.exec();
}
@

[Guest]

@#ifndef MYCLASS_H
#define MYCLASS_H
#include <QtGui/QApplication>
#include <QDeclarativeView>
#include <QDeclarativeProperty>
#include <QGraphicsObject>
#include <QObject>
#include "MyClass.h"
#include <QDebug>
#include <QDeclarativeContext>

class MyClass : public QObject
{
Q_OBJECT

public:
Q_INVOKABLE void cppMethod(const QString &msg) {

     qDebug() << "FROM QML" << msg;
 }

public:
Q_INVOKABLE void cppMethod1(int abc=100) {
qDebug() << abc;

}

public slots:
void cppSlot(int number) {
qDebug() << "Function call from QML" << number;
}
};
#endif // MYCLASS_H
@

[Guest]

Now, I want to change the color of rect2 from grey to red, how can this be done from .cpp file. Kindly give me a working solution. Thanks for your help:)

[sierdzio]

Would be much nicer to get just a condensed code from you. This amount is a tad too much, especially when it's commented-out in large amount of places.

Now that you have your C++ clas registered with QML, it's quite simple:
@
// in rect2
onClicked: {
color = object.getNewColor();
}
@

And in C++:
@
// MyClass, public section
Q_INVOKABLE QString getNewColor() { return QString("#aabbcc"); }
@

Just a quick draft, but should work.

[Guest]

thanks for your reply and suggestioon... but i would like to change the child using the setproperty in main .qml

[mlong]

Rather than an invokable method, create a Q_PROPERTY in your C++ class which has a getter, a setter, and a notify signal.