how to call qml function and get back value from it using C++

Qjay

Hey guys i want to get the HTML from this file ( Mywebview.qml ) to my C++ (dbmanager.cpp )code

what i want to do is : when a user clicks on save page button it would call parsing() from qml file and send the result to C++ code . i want to call it in add() function . Is it possible to do that ?

"in short : i want to call a qml function , function executes return some value . I want that value in C++ , so that i can save it in a file( html) "

Please look at the code here (FULL CODE ) : https://github.com/hackertron/W2L/tree/sub/storage

Pasting here all the code will look like a mess , so i am just posting Mywebview.qml code and dbmanager.cpp

dbmanager.cpp

#include "dbmanager.h"
#include <QtSql>
#include <QSqlDatabase>
#include <QSqlDriver>



dbmanager::dbmanager(QObject *parent) : QObject(parent)
{

}

void dbmanager::add()
{
    QDir databasePath;
    QString path = databasePath.currentPath()+"WTL.db";
    QSqlDatabase db = QSqlDatabase::addDatabase("QSQLITE");//not dbConnection
    db.setDatabaseName(path);
    if(!db.open())
    {
        qDebug() <<"error in opening DB";
    }
    else
    {
        qDebug() <<"connected to DB" ;
    }
    QSqlQuery query;

    if( query.exec(""))
    {
        qDebug() << "PAGE ADDED successfully";
    }
    else
    {
     qDebug() <<query.lastError();
    }
}

void dbmanager::del()
{
    qDebug() <<"DELETION CODE GOES HERE";
}

Mywebview.qml

import QtQuick 2.5
import QtQuick.Window 2.2
import QtWebEngine 1.1
import QtWebKit 3.0


Window {
    id:webview
    visible: true
    width: 600
    height: 400


    function parsing() {
        var http = new XMLHttpRequest();
        var json , parse , text , rev_id;

        http.onreadystatechange = function(){
            if(http.readyState == 4 && http.status == 200)
            { json = http.responseText;

                parse = JSON.parse(json);
                rev_id = parse.parse.revid;
                console.log(rev_id);

                text = parse.parse.text["*"];
                //console.log(text);
                 // <-- STRIP ME (o.O)
                while(text.match(/&#39;\/index.php/)){
                text = text.replace(/&#39;\/index.php/, "http://en.wikitolearn.org/index.php");
                text = text.replace(/&amp;/,"&");
                text = text.replace(/MathShowImage&amp;/, "MathShowImage&")
                text = text.replace(/mode=mathml&#39;/, "mode=mathml\"");
                text = text.replace(/<meta class="mwe-math-fallback-image-inline" aria-hidden="true" style="background-image: url\(/ ,"<img style=\"background-repeat: no-repeat; background-size: 100% 100%; vertical-align: -0.838ex;height: 2.843ex; \" src=\"");
                text = text.replace(/<meta class="mwe-math-fallback-image-display" aria-hidden="true" style="background-image: url\(/ ,"<img style=\"background-repeat: no-repeat; background-size: 100% 100%; vertical-align: -0.838ex;height: 2.843ex; \" src=\"");
                text = text.replace(/&amp;mode=mathml\"/ , "&mode=mathml>\"");

                }
                console.log(text); // after strip :p .
                webEngineView.loadHtml(text);
            }
        };
        http.open('GET','http://en.wikitolearn.org/api.php?action=parse&page=Linear%20Algebra/Sets&format=json');
        http.send();
    }


    WebView{
        id: webEngineView
        anchors.fill: parent


    }

    Component.onCompleted: parsing()



}

onek24

I took the information from this stackoverflow thread and modified it to fit your needs. I can't guarantee that it'll work since i didn't tried, but i still want to provide you the opportunity to try it yourself:

Make your function invokeable:

class DbManager {
...
    Q_INVOKABLE void add();
...
}

and then you can call this somewhere in your code. Afaik it has to be executed before you execute or start your QML, so main.cpp would be a shot.

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

and in QML Side you can do like that:

import com.myproject 1.0
...

DBManager {
     id: dbmanager
}

function parsing() {
    ...
    dbmanager.add();
}

You can also add Parameters and pass them like you call a function. Return values should be no problem too.

There might be another option, but i haven't worked with qml for some time so im not sure if its possible:

Create a signal in QML

signal addMyStuff()

Connect the Signal to a c++ function

QQuickView view;
...
QObject *object = view.rootObject();
QObject::connect(object, SIGNAL(addMyStuff()), myDatabaseObject, SLOT(add()));