Hello,
I try to read settings in C++ that are written from within QML.
But apparently, I need some delay between writing the value in QML and
reading the new value in C++ (even when calling settings.sync() in both QML
and C++).
Apparently, I have to wait about 1000ms (500ms sometimes works, sometimes
doesn't)
The following code illustrates the problem.
My QML code looks like this
import QtQuick 2.12
import QtQuick.Window 2.12
import Qt.labs.settings 1.0
Window {
id: root
visible: true
width: 640
height: 480
title: qsTr("Hello World")
property int ctr: 0
Settings {
id: settingsId
property alias ctr: root.ctr
onCtrChanged: {
console.info("QML: before C++ call ctr = "+root.ctr + "//" + ctr)
settingsId.sync();
readSettings.printSettings("try ")
Qt.callLater(tryAgain)
tryAnotherTime.start()
console.info("QML: after C++ call ctr = "+root.ctr)
}
function tryAgain() {
settingsId.sync();
readSettings.printSettings("try again ")
}
}
Timer {
id: tryAnotherTime
interval: 1000
onTriggered: readSettings.printSettings("try in timer ")
}
MouseArea {
anchors.fill: parent
onClicked: root.ctr++
}
}
The relevant C++ printSettings() function is
void ReadSettings::printSettings(QString prefix)
{
QSettings settings;
settings.sync();
int ctr = settings.value("ctr", "-1").toInt();
qInfo() << "ReadSettings::printSettings "<< prefix << " read ctr=" << ctr;
}
The ReadSettings object is registered as a context property in main.pp
When I run this code, I get the following log lines
qml: QML: before C++ call ctr = 8//8
ReadSettings::printSettings "try " read ctr= 7
qml: QML: after C++ call ctr = 8
ReadSettings::printSettings "try again " read ctr= 7
ReadSettings::printSettings "try in timer " read ctr= 8
This shows that the first two calls to printSettings still print the old value.
The call after 1000ms prints the correct value
Is this a bug? Do you see work-arounds I can try?
Kind Regards,
Marc
_______________________________________________
Interest mailing list
Interest@qt-project.org
https://lists.qt-project.org/listinfo/interest
