[Qt-qml] QDeclarativePropertyMap: bug or mistake?

[Sven Anderson]

Hi,

I'm using QDeclarativePropertyMap in my C++ extension, and I am 
experiencing some binding proplems depending on the order of the items 
in my QML file. The following test code produces a window with the text 
"before.map.key1 = XXX, after.map.key4 = undefined", although the only 
difference between the "before" and "after" item is their relative 
position to the text item. Also any updates on the map work only on the 
"before" item. I think this is a bug, but maybe I did a mistake, that I 
don't see. (The problem is not, that the map property is a (QObject *) 
instead of a (QDeclarativePropertyMap *), or that it is CONSTANT without 
NOTIFY, I tried that already.)

Here is the code:
( alternatively here: http://pastebin.com/zZChEzBj )

#include <QtGui/QApplication>
#include <QtDeclarative>
#include <QDeclarativePropertyMap>
#include "qmlapplicationviewer.h"


class MyItem : public QObject {
   Q_OBJECT
   Q_PROPERTY(QStringList keys READ Keys WRITE SetKeys)
   Q_PROPERTY(QObject *map READ Map CONSTANT)
public:
   MyItem(QObject *parent = 0) : QObject(parent) {}

   QStringList Keys() const { return map_.keys(); }
   QDeclarativePropertyMap *Map() { return &map_; }

   void SetKeys(const QStringList &keys) {
     Q_FOREACH(QString key, keys) {
       if (!map_.contains(key)) {
         map_.insert(key, QVariant(QString("XXX")));
       }
     }
   }
private:
   QDeclarativePropertyMap map_;
};


int main(int argc, char *argv[])
{
     QApplication app(argc, argv);

     QmlApplicationViewer viewer;
     qmlRegisterType<MyItem>("Test", 1, 0, "MyItem");

     viewer.setMainQmlFile(QLatin1String("qml/qmltest2/main.qml"));
     viewer.showExpanded();

     return app.exec();
}

#include "main.moc"

-------------------------------------------------------------------------------------------


import QtQuick 1.0
import Test 1.0

Rectangle {
     width: 400
     height: 200

     MyItem {
       id: before
       keys: ["key1", "key2", "key3"]
       Component.onCompleted: console.log("before item completed: " + keys)
     }

     Text {
       text: "before.map.key1 = " + before.map.key1 + ", after.map.key4 
= " + after.map.key4
       anchors.centerIn: parent
     }

     MyItem {
       id: after
       keys: ["key4", "key5", "key6"]
       Component.onCompleted: console.log("after item completed: " + keys)
     }
}