QML and Qt Quick

I think you will have to use https://doc.qt.io/qt-5/qml-qtquick-listview.html#itemAtIndex-method to get the Item before and after the current item. I think if it is not rendered it may return null. But if that is the case it should be off screen. let beforeitem = <listviewid>.itemAtIndex(index-1) let afteritem = <listviewid>.itemAtIndex(index+1) Probably need to do check with isChecked to trigger changes. Might need to be tricky and fire off events or create a signal that fires anytime any isChecked changes. You can use Qt.callLater to make sure the event is not called for every item all the time.

You should setup wireshark and check what happens exactly. At some point you wrote you had a timeout error, that's one of the thing you should resolve first it means that one side fails to connect to the other. Don't forget one important thing: your server needs to be accessible from outside of your network especially if you connect to it from a mobile device. You will have lots of items between your server and client like firewalls, NAT layers and whatnot.

I have QT Creator in Windows and Ubuntu, the version is 7.0.2, and both occurs the same problem.

There's no data because there's nothing using your CommSerial object on the QML side. By the way, calling a C++ class QmlWorker and then naming it Dlg in your QtQuick code does not make your code easy to understand.

Hello guys, I'm quite often facing the same problem. Who to fix this problem?

I've seen that and also found something online that indicated that you could pass a field width argument and if it was negative it would left align. I was really more interested in other things that you can do with C++ arg's, such as converting the base of a numeric argument. Thanks, Greg

Sorry, slightly wrong link. Here's a better one: https://doc.qt.io/qt-5/qtquickcontrols2-customize.html#customizing-button Controls 2 can be styled, and it can be done in multiple ways. I want to use a custom ProgressBarStyle, can I use a QT.Controls.1.x to make it work? Yes you can mix Controls 1 and Controls 2. But be aware that Controls 1 are: slow deprecated in Qt 5 not available in Qt 6

Well, the link I set, is from QML, it gives you basics of customising 'background' and 'contentItem'. of ScrollBar. The image you give is styled more like a Slider rather than a scrollbar.