I have an|Item|with a property. This property contains an array of
JavaScript objects which in turn contain other properties.
When I set binding for one of object's properties to some variable and
its (variable) value changes triggering the binding then all properties
in the array are reset to their initial values. I've created a small
demo to show the problem.
C++ code:
|// main.cpp
#include <QGuiApplication>
#include <QQuickWindow>
#include <QQmlApplicationEngine>
#include <QQmlContext>
class Test : public QObject
{
Q_OBJECT
Q_PROPERTY(QString emptyString READ getEmptyString NOTIFY valueChanged)
QString getEmptyString(){ return ""; }
public:
Test(QObject* parent = 0) : QObject(parent) {}
Q_INVOKABLE void triggerNotify()
{
valueChanged();
}
signals:
void valueChanged();
};
int main(int argc, char *argv[])
{
QGuiApplication app(argc, argv);
QQmlApplicationEngine engine;
Test* test = new Test(&engine);
engine.rootContext()->setContextProperty("__test__", (QObject*)test);
QObject::connect(&engine, &QQmlApplicationEngine::objectCreated,
[](QObject* rootObject) {
QQuickWindow *appWindow = qobject_cast<QQuickWindow *>(rootObject);
appWindow->show();
});
engine.load(QUrl(QStringLiteral("qrc:/ui/main.qml")));
return app.exec();
}|
QML code:
|// main.qml
import QtQuick 2.4
import QtQuick.Controls 1.3
ApplicationWindow {
id: container
visible: true
width: 640
height: 480
property int clicksCounter: 0
Item {
id: testObject
property var myArray: [{
name: "CustomName" + __test__.value,
boolFlag: false
}]
}
Rectangle {
x: 10
y: 10
width: 100
height: 100
color: "red"
MouseArea {
anchors.fill: parent
onClicked: {
container.clicksCounter++
console.log("CLICK #" + container.clicksCounter+ "[RED SQUARE] :
Set testObject.myArray[0] to TRUE\n")
testObject.myArray[0].boolFlag= true
console.log("CLICK #" + container.clicksCounter+ "[RED SQUARE] :
DONE\n")
}
}
}
Rectangle {
x: 120
y: 10
width: 100
height: 100
color: "blue"
MouseArea {
anchors.fill: parent
onClicked: {
container.clicksCounter++
console.log("CLICK #" + container.clicksCounter+ "[BLUE SQUARE] :
Triggering notify by calling C++ <Test::valueChanged> method \n")
console.log("CLICK #" + container.clicksCounter+ "[BLUE SQUARE] :
[BEFORE] testObject.myArray[0].name:" + testObject.myArray[0].name+ ',
testObject.myArray[0].boolFlag:' + testObject.myArray[0].boolFlag)
__test__.valueChanged()
console.log("CLICK #" + container.clicksCounter+ "[BLUE SQUARE] :
[AFTER] testObject.myArray[0].name:" + testObject.myArray[0].name+ ',
testObject.myArray[0].boolFlag:' + testObject.myArray[0].boolFlag)
}
}
}
}|
Here is what I get:
qml: CLICK #1[RED SQUARE] : Set testObject.myArray[0] to TRUE
qml: CLICK #1[RED SQUARE] : DONE
qml: CLICK #2[BLUE SQUARE] : Triggering notify by calling C++
<Test::triggerNotify> method
qml: CLICK #2[BLUE SQUARE] : [BEFORE] testObject.myArray[0].name:
CustomName, testObject.myArray[0].boolFlag: true
qml: CLICK #2[BLUE SQUARE] : [AFTER] testObject.myArray[0].name:
CustomName, testObject.myArray[0].boolFlag: false
So what happens here is that after I set testObject.myArray[0].boolFlag
from FALSE to TRUE and call test.triggerNotify() method my flag
automatically resets to its initial value. Same goes if any other type
used - int, string, etc. Why does this happen?
[UPDATE] QT 5.5 is used, Visual Studio 2013 Update 4 x32.
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