[Qt-interest] QML signal connections

[Carl Snellman]

Oh, wasn't aware of such list...
Reposting.
Thanks!

Carl

On Wed, Aug 18, 2010 at 11:14 AM, Jason H <scorp1us at yahoo.com> wrote:
> you also might want to try the QML list...
>
>
>
> ----- Original Message ----
> From: Carl Snellman <carl.snellman at gmail.com>
> To: Qt Interest <Qt-interest at trolltech.com>
> Sent: Wed, August 18, 2010 2:32:58 AM
> Subject: [Qt-interest] QML signal connections
>
> Hey,
>
> I'm trying to use QML with C++ to create the GUI for my application,
> but I bumped to a problem I havent' been able to solve after a day of
> studying/trying.
>
> I created a button in QML, and I'd like to connect its signal to a C++
> class slot so that I get to react to the button press; Just like you
> would connect QPushButton. However, I cannot figure out how to make
> this connection. I tried to find the child object, but always return
> null, so I cannot connect that way. I dont know how I would make the
> connection in the QML file side (if it is possible)
>
> I attached minimal app below to demonstrate what I've tried.
> Any help is greatly appreciated!
> Thanks,
> Carl
>
> main.cpp
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
> #include <QtGui/QApplication>
> #include <QtDeclarative>
> class MyType : public QObject {
>    Q_OBJECT
> public:
>    MyType(QObject *parent = 0) : QObject(parent) {}
> public slots:
>    void doSomething() {
>        qDebug() << "DoSomething!";
>    }
> };
>
> int main(int argc, char *argv[]) {
>    QApplication a(argc, argv);
>    qmlRegisterType<MyType>("MyType", 1,0, "MyType");
>
>    QGraphicsView *graphicsView = new QGraphicsView;
>    graphicsView->setGeometry(QRect(0, 0, 500, 500));
>    QGraphicsScene* scene = new QGraphicsScene(0, 0, 500, 500);
>    graphicsView->setScene(scene);
>
>    QDeclarativeEngine *engine = new QDeclarativeEngine;
>    QDeclarativeComponent component(engine, QUrl("qrc:/myqml.qml"));
>    QDeclarativeItem *root = qobject_cast<QDeclarativeItem
> *>(component.create());
>    scene->addItem(root);
>
>    //QObject* rect = root->findChild<QObject*>("button");
>    QObject* button = qFindChild<QObject*>(root, QString("button"));
>    if(button) {
>        MyType *mytype = new MyType;
>        QObject::connect(button, SIGNAL(clicked()), mytype,
> SLOT(doSomething()));
>    }
>
>    graphicsView->show();
>    return a.exec();
> }
> #include "main.moc"
> <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<
>
> res.qrc
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
> <RCC>
>    <qresource prefix="/">
>        <file>myqml.qml</file>
>    </qresource>
> </RCC>
> <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<
>
> myqml.qml
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
> import Qt 4.7
> //import MyType 1.0
> Item {
>     id: screen
>     width: 500; height: 500;
>     Rectangle {
>         id: button
>         signal clicked
>         width: 200; height: 200; color: "red"
>         MouseArea {
>             anchors.fill: parent
>             onClicked: {
>                 button.color = "blue";
>                 button.clicked();
>             }
>         }
>     }
> //     MyType {
> //         id: mytype1
> //     }
> //     Connections {
> //         target: button
> //         onClicked:  ??????
> //     }
> }
> <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<
>
> QMLConnectTest.pro
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
> QT       += core gui declarative
> TARGET = QMLConnectTest
> TEMPLATE = app
> RESOURCES += res.qrc
> SOURCES += main.cpp
> OTHER_FILES += myqml.qml
> <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<
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