QML and C++ interaction

[cueMan]

Ah, forgot to mark the function I wish to run in C++ with Q_INVOKABLE. Now works.

[technoViking]

Hi,

I'm having the same issue, can you post how you got it working? the C++ function you just have to surround with Q_+INVOKABLE?

WHat if you want to send a SIGNAL from QML that has data the user entered (from QML). to a C++ slot that will process that data.

[cueMan]

Haven't yet needed a signal slot mechanism between QML and Qt but here's how you can call C++ code from QML:

First you need your class:

#include <QObject>
 
class MyClass : public QObject
{
    Q_OBJECT
public:
    explicit MyClass(QObject *parent = 0);
 
    Q_INVOKABLE void doThisAndThat(QString myString);
    Q_INVOKABLE QString getThisAndThat();
 
signals:
 
public slots:
 
private:
 
    QString localThisAndThat;
};

#include <QObject>

class MyClass : public QObject
{
    Q_OBJECT
public:
    explicit MyClass(QObject *parent = 0);

    Q_INVOKABLE void doThisAndThat(QString myString);
    Q_INVOKABLE QString getThisAndThat();
    
signals:

public slots:

private:

    QString localThisAndThat;
};

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And you can create the implementation as you wish, no need to use the Q_INVOKABLE on the implementation side, though.

The you need to introduce this class to QML like this:

QDeclarativeView::rootContext()->setContextProperty("qmlReferenceName", myClass);

QDeclarativeView::rootContext()->setContextProperty("qmlReferenceName", myClass);

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So you just give a string of your choice to qmlReferenceName, and pass your class on myClass. After this, you have this class as a global scope variable within your QML code:

Rectangle {
   MouseArea {
      anchors.fill: parent
      onClicked: { qmlReferenceName.doThisAndThat("It works!") }
   }
 
   Text {
      text: qmlReferenceName.getThisAndThat()
 
   }
}

Rectangle {
   MouseArea {
      anchors.fill: parent
      onClicked: { qmlReferenceName.doThisAndThat("It works!") }
   }
   
   Text {
      text: qmlReferenceName.getThisAndThat()

   }
}

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