Objective c with Qt side by side

Q: main.cpp or main.mm?
A: if the class is following cpp format and the .h is following c++ then main.cpp or main.mm can be used.
if the .h file is following objective-c then main.cpp should be renamed to main.mm

Remarks: 
-with .mm the simulator may not work and gives you an error, try it on a real device.
-NSLog doesn't show in the console if the app is executed from Qt Creator. Open the project in XCode and then the NSLog messages will show


TestNS.mm

 #include "TestNS.h"

#include <QDebug>

#include<Foundation/Foundation.h>

TestNS::TestNS(QObject *parent) : QObject(parent){

}

void TestNS::test(){

    NSLog(@"\n\n\n***\n***\n***\nThis is a test");

}

TestNS.h

#ifndef TESTNS_H

#define TESTNS_H

#include <QObject>

class TestNS : public QObject

{

    Q_OBJECT

public:

    explicit TestNS(QObject *parent = 0);

    Q_INVOKABLE void test();

signals:

public slots:

};

#endif

main.cpp

#include <QGuiApplication>

#include <QQmlApplicationEngine>

#include "TestNS.h"

int main(int argc, char *argv[])

{

    QGuiApplication app(argc, argv);

    qmlRegisterType<TestNS>("TestNS.com", 1, 0, "TestNS");

    QQmlApplicationEngine engine;

    TestNS * testns = new TestNS();

    testns->test();

    engine.load(QUrl(QStringLiteral("qrc:/main.qml")));

    return app.exec();

}

main.qml

import QtQuick 2.0

import TestNS.com 1.0

Item {

    Rectangle{

        radius: 5

        anchors.horizontalCenter: parent.horizontalCenter

        anchors.verticalCenter: parent.verticalCenter

        color: "green"

        width: parent.width/2

        height: parent.height/2

        MouseArea{

            anchors.fill: parent

            onClicked:{

                console.debug("clicked")

                testns.test()

            }

        }

    }

    TestNS{

        id: testns

    }

}

Special Thanks to Mike Krus's video: see https://www.youtube.com/watch?v=8A7DPUwIcDg