Using Q_INVOKABLE with BB10

Ever used Q_INVOKABLE ?

OK !! Let's know the use behind this.

If you want to communicate b/w QML file and cpp file, i.e if you like to call a method of cpp file from QML, then we have to take help of Q_INVOKABLE.In-order to let QML file know( discover ) the method in cpp file, we have to declare the method as Q_INVOKABLE.

Practically,In hpp file, declare the method like this.

Q_INVOKABLE void onButtonClicked();

In cpp file, define this method and make cpp file object available to QML using context property of QMLDocument.

QmlDocument *qml = QmlDocument::create("asset:///main.qml").parent(this);
// create root object for the UI
pane = qml->createRootObject(); // set created root object as a scene
app->setScene(pane);

qml->setContextProperty("cppObj", this);

In the last line of above code, I'm referencing cpp class object as "cppObj". So with this name, i can call method's of this object.

Lastly, in QML file make a call for the method.

Button {
    text: qsTr("Click me")
    verticalAlignment: VerticalAlignment.Center
    horizontalAlignment: HorizontalAlignment.Center
    onClicked: {
       cppObj.onButtonClicked();
     }
  }

Don't forget, decalring Q_OJECT in .hpp file.

The complete example is illustrated in this post.