Test

boot.cpp

#include "boot.h"
#include <QCoreApplication>
#include <QDebug>
#include <QThread>
#include <QTimer>

Boot::Boot(QObject *parent) : QObject(parent)
{

}

void Boot::load()
{
    loadXMLContent();
}

QString Boot::errorMsg()
{
    return m_errorMsg;
}

void Boot::setErrorMsg(const QString &errorMsg)
{
    if(m_errorMsg == errorMsg)
        return;

    m_errorMsg = errorMsg;
    emit errorMsgChanged();
}

QString Boot::xmlContent()
{
    return m_xmlContent;
}

void Boot::setXmlContent(const QString &xmlContent)
{
    if(m_xmlContent == xmlContent)
        return;
    m_xmlContent = xmlContent;
    emit xmlContentChanged();
}


bool Boot::loadXMLContent()
{
    bool res;
    timer = new QTimer(this);

    setErrorMsg("Parsing channels.xml");
    setErrorMsg("Trying to open channels.xml");

    channelsList.open("config/channels.xml");


    if(!channelsList.is_open())
    {
        setErrorMsg("There was an error opening channels.xml");
        res = false;
    }
    else
    {
        setErrorMsg("channels.xml was opened successfully");
        setErrorMsg("now reading from channels.xml");

        connect(timer, &QTimer::timeout, [this](){
            if(!channelsList.eof())
            {
                std::string temp;
                getline(channelsList, temp);
                QString qTemp = QString::fromStdString(temp);
                setErrorMsg("Parsing " +qTemp);
                tempXMLContent += qTemp+"\n";
            }
            else{
                setXmlContent(tempXMLContent);
                setErrorMsg("Parsing is complete");

            }

        });
        timer->start(10);

        res = true;
    }

    return res;
}

boot.h

#ifndef BOOT_H
#define BOOT_H

#include <QObject>
#include <fstream>
class QTimer;

class Boot : public QObject
{
    Q_OBJECT
    Q_PROPERTY(QString errorMsg READ errorMsg NOTIFY errorMsgChanged)
    Q_PROPERTY(QString xmlContent READ xmlContent NOTIFY xmlContentChanged)

public:
    explicit Boot(QObject *parent = nullptr);
    Q_INVOKABLE void load();
    bool loadXMLContent();
    QString errorMsg();
    void setErrorMsg(const QString &errorMsg);

    QString xmlContent();
    void setXmlContent(const QString &xmlContent);


signals:
    void errorMsgChanged();
    void xmlContentChanged();

private:
    QString m_errorMsg;
    QString m_xmlContent;
    QTimer *timer;
    QString tempXMLContent;
    std::ifstream channelsList;
};

#endif // BOOT_H

main.cpp

#include "boot.h"

#include <QGuiApplication>
#include <QQmlApplicationEngine>
#include <QQuickView>

#include <QQmlEngine>

int main(int argc, char *argv[])
{
    QGuiApplication app(argc, argv);
    QCoreApplication::setApplicationName("xyz");
    QCoreApplication::setAttribute(Qt::AA_X11InitThreads);


    QQuickView quickView;
    qmlRegisterType<Boot>("xyz", 1, 0, "Boot");
    quickView.setSource(QUrl(QStringLiteral("qrc:/main.qml")));
    quickView.setResizeMode(QQuickView::SizeRootObjectToView);
    quickView.show();

    return app.exec();
}

main.qml

import QtQuick 2.0
import "."
import QtQuick.XmlListModel 2.0
import xyz 1.0

Item{
Timer {
    id: timer
}

function delay(delayTime, cb) {
    timer.interval = delayTime;
    timer.repeat = false;
    timer.triggered.connect(cb);
    timer.start();
}

Loader{
    id: bootPageLoader
    anchors.fill:parent
    sourceComponent: bootSystem
    focus:true
}

Component{
    id:bootSystem

    Rectangle{
        width: 640
        height: 480
        color:"black"
        focus:true

        Component.onCompleted: {
            booting.load();
        }

        Boot{
            id:booting
            onErrorMsgChanged: {
                 console.log("New Boot Log Message: " + errorMsg);
                 //This is where I am adding to the listview every time I receive a signal
                 logModel.append({msg:errorMsg});
                 log.positionViewAtEnd();

            }
       }

       ListView {
           id:log
           anchors.left: parent.left
           anchors.leftMargin: 10
           anchors.topMargin: 10
           anchors.bottomMargin:10
           anchors.top: parent.top
           width:(parent.width*40)/100
           height:parent.height-20

           model: ListModel{
               id:logModel
           }
           delegate: Text {
               text: msg
               color: "green"
               font.pixelSize: 15
           }
       }

       Text{
           id: loading
           anchors{
               horizontalCenter: parent.horizontalCenter
               verticalCenter: parent.verticalCenter
           }

           text: "LOADING..."
           color: "white"
           font.pixelSize: Math.round(parent.height/20)
           font.bold: true
       }
   }
}
}

qml.qrc

<RCC>
    <qresource prefix="/">
        <file>main.qml</file>
    </qresource>
</RCC>

TestQML.pro

TEMPLATE = app

QT += qml quick
CONFIG += c++11

SOURCES += main.cpp \
    boot.cpp

RESOURCES += qml.qrc

# Additional import path used to resolve QML modules in Qt Creator's code model
QML_IMPORT_PATH =

# Additional import path used to resolve QML modules just for Qt Quick Designer
QML_DESIGNER_IMPORT_PATH =

# The following define makes your compiler emit warnings if you use
# any feature of Qt which as been marked deprecated (the exact warnings
# depend on your compiler). Please consult the documentation of the
# deprecated API in order to know how to port your code away from it.
DEFINES += QT_DEPRECATED_WARNINGS

# You can also make your code fail to compile if you use deprecated APIs.
# In order to do so, uncomment the following line.
# You can also select to disable deprecated APIs only up to a certain version of Qt.
#DEFINES += QT_DISABLE_DEPRECATED_BEFORE=0x060000    # disables all the APIs deprecated before Qt 6.0.0

# Default rules for deployment.
qnx: target.path = /tmp/$${TARGET}/bin
else: unix:!android: target.path = /opt/$${TARGET}/bin
!isEmpty(target.path): INSTALLS += target

HEADERS += \
    boot.h

What if I want to read a file? here is my code

`
bool Boot::loadXMLContent()
{
bool res;
ifstream channelsList;
QString tempXMLContent;

setErrorMsg("Parsing channels.xml");
setErrorMsg("Trying to open channels.xml");

channelsList.open("config/channels.xml");


if(!channelsList.is_open())
{
    setErrorMsg("There was an error opening channels.xml");
    res = false;
}
else
{
    setErrorMsg("channels.xml was opened successfully");
    setErrorMsg("now reading from channels.xml");

    while(!channelsList.eof())
    {
        string temp;
        getline(channelsList, temp);
        QString qTemp = QString::fromStdString(temp);

        setErrorMsg("Parsing " +qTemp);
        tempXMLContent += qTemp+"\n";
    }

    setXmlContent(tempXMLContent);

    setErrorMsg("Parsing is complete");

    res = true;
}


return res;

}`
This is the code of XmlContent

in boot.h add
Q_PROPERTY(QString xmlContent READ xmlContent NOTIFY xmlContentChanged)
QString xmlContent(); void setXmlContent(const QString &xmlContent);
void xmlContentChanged();
QString m_xmlContent;

here is channels.xml
channels.xml

@Muhand For a few lines the effect is not visible as you have noticed, add more lines and you will see, if you want to be slower you can change the timer to a longer time.