Hi,I wrote a blog post about exchanging things between QML <-> C++ quite some time ago:
http://ruedigergad.com/2011/11/13/exchange-data-and-objects-between-c-and-qml-and-vice-versa/
I am not explicitly covering signals there, iirc, but when you define a Q_PROPERTY in C++ with a defined NOTIFY then you can use the usual QML way of handling signals: 'onFooChanged: console.log("bar")'. See, e.g., C++ class A in the example. Of course, you can also use simple signals as well. Just remember that the C++ signal "bar()" will be "onBar" in QML.
Personally, I found it easiest to expose C++ objects to QML via the qmlRegisterType mechanism as explained in that post. I always found the approach of setting context properties to be artificially limiting and not straight forward.
I hope this helps. Regards Ruediger On 05/08/2013 09:27 PM, christopher.l...@thurweb.ch wrote:
Hi Superpelican Why don't you post the QML / UI part of your code, so we can see how you think your QML should respond to your QDeclarativePropertyMap? Does your PropertyMap have an onXXXXChanged event? That would be one QML way of allowing UI components to respond to property changes. You could also try posting this question on the Qt Project Forum - I suspect it is more of a Qt question than a SailfishOS specific one, so you could leverage all the Qt knowledge there. Grüsse Chris Zitat von Superpelican <superpeli...@zoho.com>:I'm trying to create a hybrid QML/C++ application, where the logic is written in C++ and the interface is QML/Sailfish Silica based. I'm currently playing around with the different ways to let QML/C++ communicate with each other. I currently have this code: <code> #include <QApplication> #include <QGraphicsObject> #include <QDir> #include <QDeclarativeView> #include <QDeclarativeContext> #include <QDeclarativeEngine> #include <QDeclarativeComponent> #include <QDebug> #include <QDeclarativePropertyMap> #ifdef HAS_BOOSTER #include <MDeclarativeCache> #endif Q_DECL_EXPORT int main(int argc, char *argv[]) { #ifdef HAS_BOOSTER QScopedPointer<QApplication> myapp(MDeclarativeCache::qApplication(argc, argv)); #else QScopedPointer<QApplication> myapp = new QApplication(argc, argv); #endif #ifdef HAS_BOOSTER QScopedPointer<QDeclarativeView> appview(MDeclarativeCache::qDeclarativeView()); #else QScopedPointer<QDeclarativeView>(new QDeclarativeView); #endif QDeclarativePropertyMap binding_map; binding_map.insert("question_txt", QVariant(QString("5 * 5 ="))); binding_map.insert("color", QVariant(QString("dark red"))); QScopedPointer<QDeclarativeContext> binding_context(appview->rootContext()); binding_context->setContextProperty("binding_map", &binding_map); QString file = "main.qml"; QString path = QString(DEPLOYMENT_PATH); appview->setSource(QUrl::fromLocalFile(path + file)); appview->setResizeMode(QDeclarativeView::SizeRootObjectToView); appview->setAttribute(Qt::WA_OpaquePaintEvent); appview->setAttribute(Qt::WA_NoSystemBackground); appview->viewport()->setAttribute(Qt::WA_OpaquePaintEvent); appview->viewport()->setAttribute(Qt::WA_NoSystemBackground); appview->showFullScreen(); binding_map["question_txt"] = QVariant(QString("overwritten 5 * 5 =")); return myapp->exec(); } </code> I need to let C++ print text in the QML interface (the question) and C++ has to obtain the answer the user has answered in the QML interface (TextField Silica component). That's basically the needed communication between C++ and QML. So I thought that I'd create a QDeclarativePropertyMap in C++. This propertymap will contain the question. My program has a while loop that asks the user new questions each time the loop runs(the logic code can be found here <https://bitbucket.org/Superpelican/clamshell_cli>, but it hasn't been adjusted for use with a GUI, it's currently a CLI application). So I need to constantly update the QML UI from C++ while the programs running, after I've setup the QDeclarativeView etc. However I noticed that if you change a value in the propertymap after initializing and showing the QDeclarativeView, the UI won't be updated! I thought the QDeclarativePropertyMap was dynamic! http://qt-project.org/doc/qt-4.8/qdeclarativepropertymap.html#details: "The binding is dynamic - whenever a key's value is updated, anything bound to that key will be updated as well." Kind Regards, Superpelican_______________________________________________ SailfishOS.org Devel mailing list
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