qml QListview updating slow by c++

bladekel

I'm updating the qml Listview from c++ like;

in main.cpp;

listeci frmlisteci;
engine.rootContext()->setContextProperty("listeElemanlar", &frmlisteci.listeElemanlar);

in Liste.qml;

        ListView{
            id: listeciElemanlar
            anchors.fill: parent
            model: listeElemanlar
            delegate: Text{
                text: display
                verticalAlignment: Text.AlignBottom
                width : parent.width
                color: textRengi
                font.pointSize: 30
                leftPadding: 20
            }}

in listeci.h;

public:
    QStringListModel listeElemanlar;
private:
    QStringList userAyarlari;

in listeci.cpp;

listeci::listeci(QObject *parent) : QObject(parent)
{

    // Kullanıcı ayarları elemanları
    userAyarlari.append("Kullanıcı ayarı 01");
    userAyarlari.append("Kullanıcı ayarı 02");
    userAyarlari.append("Kullanıcı ayarı 03");
    userAyarlari.append("Kullanıcı ayarı 04");
    userAyarlari.append("Kullanıcı ayarı 05");
    userAyarlari.append("Kullanıcı ayarı 06");
    userAyarlari.append("Kullanıcı ayarı 07");
    userAyarlari.append("Kullanıcı ayarı 08");
    userAyarlari.append("Kullanıcı ayarı 09");
    userAyarlari.append("Kullanıcı ayarı 10");
    userAyarlari.append("Kullanıcı ayarı 11");
    userAyarlari.append("Kullanıcı ayarı 12");
    userAyarlari.append("Kullanıcı ayarı 13");
    userAyarlari.append("Kullanıcı ayarı 14");
    userAyarlari.append("Kullanıcı ayarı 15");
    userAyarlari.append("Kullanıcı ayarı 16");
    userAyarlari.append("Kullanıcı ayarı 17");
    userAyarlari.append("Kullanıcı ayarı 18");
    userAyarlari.append("Kullanıcı ayarı 19");
}
void listeci::listeGuncelle()
{
    listeElemanlar.setStringList(userAyarlari);
}

with these lines, I can successfully create a list and show on qml Listview, when I clicked on a button on qml side by calling

frmlisteci.listeGuncelle()

But when I do this procedure after a mount,( we can say refreshing the list) the code becoming slow, and waiting on this line:

listeElemanlar.setStringList(userAyarlari);

What can be the reason ?

Edit : 1

I just discover sth.

On my project, I have 5 qml pages and I'm navigating between the pages with "Stackview".

Here is the construction of stackview.

        // Sayfa bölmesi
        StackView {
            id: stackci
            initialItem: manuelSayfa
            anchors.fill : sayfaBolmesi

            pushEnter: Transition {
                PropertyAnimation {
                    property: "opacity"
                    from: 0
                    to: 1
                    duration: 0
                }
            }
            pushExit: Transition {
                PropertyAnimation {
                    property: "opacity"
                    from: 1
                    to: 0
                    duration: 0
                }
            }
        }

        Component{
            id:manuelSayfa
            Manuel{}
        }

        Component{
            id:otomatikSayfa
            Otomatik{}
        }

        Component{
            id:ayarlaraGirisSayfa
            AyarlaraGiris{}
        }

        Component{
            id:listelerSayfa
            Liste{}
        }

        Component{
            id:bilgiSayfa
            Bilgi{}
        }

And I'm navigating the pages with a signal from c++ like;

on main.qml

    Connections{
        target: sayfaDegistirmeReferansi
        onSayfaDegistir:{
            sayfaDegistir(s)
        }
    }

.......

function sayfaDegistir(sayfa)
    {
         if(sayfa == 100) stackci.push(manuelSayfa)
         .......
    }

on main.cpp

    engine.rootContext()->setContextProperty("sayfaDegistirmeReferansi",&frmkeypad);

My algorithm is like, when I send a signal to qml from c++, it first refresh the list, than open the page.

The thing that I discovered is, when I refresh the list with MouseArea ( also same with signal from c++), it doesnt make a delay on refreshing the list.

The difference is, I dont reload the page, only reloading the list....

So what can be the problem ????

Edit : 2

I solved the problem.

It is caused by stackview. I had used push method for changing the page.

When I changed push method by replace, everything started to work well.....

VRonin

@bladekel said in qml QListview updating slow by c++:

this procedure after a mount

What's a mount?

waiting on this line:
listeElemanlar.setStringList(userAyarlari);

This is probably due to the model having to reset itself completely. can you edit it instead?
Also to test the speed with C++ and QML interactions use the release build, the debug becomes pretty heavy

bladekel

@VRonin
amount is not so much. It increase by every call such as on 10th 1sec waiting, on 20th 2sec waiting ... and so on....

bladekel

I discovered sth and edit my first post....