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Cannot modify Qml propriety from Cpp

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  • W Offline
    W Offline
    wspilot
    wrote on last edited by
    #4

    Try this:
    objectName: "buttonOpenCloseCom"

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    • M Offline
      M Offline
      mikecurl91
      wrote on last edited by
      #5

      There is yet the objectName proprety.
      I've tried this solution... but doesn't work.
      [quote author="wspilot" date="1376930837"]Try this:
      objectName: "buttonOpenCloseCom"[/quote]

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      • W Offline
        W Offline
        wspilot
        wrote on last edited by
        #6

        In your code it is still an identifier/var or whatever, but not a string
        objectName: buttonOpenCloseCom
        not
        objectName: “buttonOpenCloseCom”

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        • M Offline
          M Offline
          mikecurl91
          wrote on last edited by
          #7

          Excuseme but in the code:
          @
          Button
          {
          id: buttonOpenCloseCom
          objectName: buttonOpenCloseCom
          text:applicationwindow.buttonComText
          enabled: true
          }
          @

          objectName: “buttonOpenCloseCom” there is![/quote]

          what is the problem you talk about?!

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          • sierdzioS Offline
            sierdzioS Offline
            sierdzio
            Moderators
            wrote on last edited by
            #8

            Put it in quotes: ". Not just string but "string".

            (Z(:^

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            • W Offline
              W Offline
              wspilot
              wrote on last edited by
              #9

              @ Button
              {
              id: buttonOpenCloseCom
              objectName: "buttonOpenCloseCom"
              text:applicationwindow.buttonComText
              enabled: true
              }@

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              • M Offline
                M Offline
                mikecurl91
                wrote on last edited by
                #10

                I've understand what you mean, and I've tried with the correction, but the result is the same as before.
                Debugging i've see that the root object is correctly the "applicationwindow",
                but when I try to find the child, it fails and return a null pointer...
                in "this":http://qt-project.org/doc/qt-5.1/qtqml/qtqml-cppintegration-interactqmlfromcpp.html#loading-qml-objects-from-c reference it used QQuickView, and not QQuickWindow to handle the root object...
                Could it be a problem?
                If yes, how can I resolve it? any suggestions?

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                • mranger90M Offline
                  mranger90M Offline
                  mranger90
                  wrote on last edited by
                  #11

                  The problem is that you make the change after the return() statement.
                  Nothing after that will be executed.

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                  • M Offline
                    M Offline
                    mikecurl91
                    wrote on last edited by
                    #12

                    I've modified the code:
                    @int main(int argc, char *argv[])
                    {
                    QGuiApplication app(argc, argv); //preparo l'applicazione
                    QQmlApplicationEngine engine(QUrl("qml/main.qml")); //carico l'interfaccia
                    QObject *radice = engine.rootObjects().value(0); //identifico la radice
                    QQuickWindow *applicationwindow = qobject_cast<QQuickWindow *>(radice); //acquisisco in C++ l'ogg QML ApplicationWindow
                    if ( !applicationwindow )
                    {
                    qWarning("Error: Your root item has to be a Window.");
                    return -1;
                    }
                    QObject button = radice->findChild<QObject>("buttonOpenCloseCom",Qt::FindChildrenRecursively);
                    if (button)
                    {
                    button->setProperty("text", "Open");
                    qDebug()<<"found!";
                    }
                    else
                    {
                    button->setProperty("text", "Open");
                    qDebug()<<"not found!";
                    }

                    applicationwindow->show();
                    return app.exec();
                    

                    }@

                    but is the same as before...
                    [quote author="mranger90" date="1376947874"]The problem is that you make the change after the return() statement.
                    Nothing after that will be executed.[/quote]

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                    • sierdzioS Offline
                      sierdzioS Offline
                      sierdzio
                      Moderators
                      wrote on last edited by
                      #13

                      One drawback of QML is that it's mightily hard to explain certain things... In order for this to work (IMO) you need to do that property manipulation outside of "main.cpp":https://github.com/sierdzio/closecombatfree/blob/master/src/ccfmain.cpp so for example in a QObject that gets initialised somewhere later. Same as with QWidgets or console apps in Qt: you need to have a working event loop for moc to work.

                      One possible alternative would be to modify the property using Qt::QueuedConnection, or the infamous singleshot QTimer.

                      (Z(:^

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