Qt: How to replace number (Start, End) in a JSON from server

Jerwinprabu

This is how my JSON file looks like. As you can see, the start_x, start_y, and end_x, end_y, degree_of_rotation is a number.

{
    "ID" : "ROLL1",
"action" : "start",
  "zone" :
    {
        "start_x" : 0,
        "start_y" : 4,

        "end_x" : 10,
        "end_y" : 5,

    "motion" :
    {
        "motion_type": "xxxxxx",
        "degree_of_rotation": 30,
        "rotation_direction": "yyyyyy",
        "linear_direction": "+ve"
    }
    }
}

How can I replace and save the number in JSON from the server? Currently, this is what I have. Qt5 has a new JSON parser and I want to use it. The problem is that it isn't too clear about what the functions do

void JsonFileread::Json_File_Function()
{
    try
    {
        qDebug() <<"file reading";

        file.setFileName("/home/JSON/jsonfile.js");   
        file.open(QIODevice::ReadOnly | QIODevice::Text);

        QFileDevice::FileError err = QFileDevice::NoError;

        if(!file.open(QIODevice::ReadOnly | QIODevice::Text))
        {
            qDebug() <<"Could not open file : "<<file.fileName() <<"for reading :"<<file.errorString()<<endl;
            errMsg =file.errorString();
            err =file.error();
            cout<<"err : "<<err<<endl;
        }

        settings = file.readAll(); 

        if (file.error() != QFile::NoError) {
               qDebug() << QString("Failed to read from file %1, error: %2").arg(file.fileName()).arg(file.errorString());
           }

        if (settings.isEmpty()) {
                qDebug() << "No data was currently available for reading from file" << file.fileName();
            }

        file.close();

        object = EchoClient::jsonstringflag;

        QJsonDocument sd = QJsonDocument::fromJson(settings.toUtf8()); 
        QJsonObject sett2 = sd.object(); 

        QJsonValue mainid = sett2["ID"];
        mainid = mainid.toString();

        QJsonValue action = sett2["action"];
        actionstring = action.toString();

        QJsonValue value = sett2.value(QString("zone")); 
        QJsonObject item = value.toObject();

        QJsonValue startx = item["start_x"]; 
        startvaluex = startx.toInt();

        QJsonValue starty = item["start_y"];
        startvaluey = starty.toInt();

        QJsonValue endx = item["end_x"]; 
        endvaluex = endx.toInt();

        xendvaluestring = endx.toString();
        qWarning() << endvaluex<<endl;

        QJsonValue endy = item["end_y"]; 
        endvaluey = endy.toInt();

        yendvaluestring = endy.toString();
        qWarning() << endvaluey<<endl;

        QJsonValue motion = item.value(QString("motion"));
        QJsonObject motion_object = motion.toObject();

        QJsonValue motiontype = motion_object["motion_type"];
        motiontypestring = motiontype.toString();

        QJsonValue directionlinear = motion_object["linear_direction"];
        lineardirection = directionlinear.toString();

        QJsonValue rotatingangle = motion_object["degree_of_rotation"];
        angleofrotation = rotatingangle.toInt();
    }

    catch (QJsonParseError error)
        {
            qDebug() <<  error.errorString();
        }
    catch(...)
        {
            qDebug() <<  "due to some other error";
        }
}

this is only about reading JSON values, I don't know how to change or replace, For example, consider the above code, reading the ''start_x, start_y, and end_x, end_y'' then this value sent to the server. Now, I have received the value from the server, but whenever we received ''start_x, start_y, and end_x, end_y" value, JSON value should change or replace according to that value. Ex: ('Startx 0 replace5 (startx 5), starty 4 to starty 7' ). Receive JSON data from the server to client(Processor), received value will replace to JSON each and every time.

SGaist

Hi,

Your question seems similar that thread.

Hope it helps