Help with QTreeWidget list of contacts XMPP

[SirJonas]

Hi i am trying to do one project like webrtc but in small. In this chat i will have users connected and offline. I tried to do one easy example with QTreeWidget still i'm trying to solve this issue. My problem is when i add a new contact in my account, the contact old is deleted and the new is created. The problem is when i add the child.
Code:

logado = true; //contacts
    ui->frameLogin->show();
    ui->frameConexion->show();
    int i,j;
    QTreeWidgetItem *item = new QTreeWidgetItem();
    QStringList contactos = cliente.rosterManager().getRosterBareJids();
    for(i=0;i<contactos.length();i++)
    { 
        item->setText(0,contactos[i]);
        QStringList recursos = cliente.rosterManager().getResources(contactos[i]);
        QIcon online;
        online.addFile(":/icons/user-offline.png");
        item->setIcon(0,online);
        for(j=0;j<recursos.length();j++)
        {
            item->addChild(item);
            item->child(j)->setText(0,recursos[j]);
            online.addFile(":/icons/user-online.png");
            item->setIcon(0,online);
            item->child(j)->setIcon(0,online);
 
 
        }
        listaItems.append(item);
    }
    ui->arbolConectados->addTopLevelItems(listaItems);

logado = true; //contacts
    ui->frameLogin->show();
    ui->frameConexion->show();
    int i,j;
    QTreeWidgetItem *item = new QTreeWidgetItem();
    QStringList contactos = cliente.rosterManager().getRosterBareJids();
    for(i=0;i<contactos.length();i++)
    { 
        item->setText(0,contactos[i]);
        QStringList recursos = cliente.rosterManager().getResources(contactos[i]);
        QIcon online;
        online.addFile(":/icons/user-offline.png");
        item->setIcon(0,online);
        for(j=0;j<recursos.length();j++)
        {
            item->addChild(item);
            item->child(j)->setText(0,recursos[j]);
            online.addFile(":/icons/user-online.png");
            item->setIcon(0,online);
            item->child(j)->setIcon(0,online);


        }
        listaItems.append(item);
    }
    ui->arbolConectados->addTopLevelItems(listaItems);

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Any idea is good. It's only in the child doesnt add me one child insted of create me a new child and delete me the old.