Is it possible to initalize ApplicationWindow before Component.onCompleted is done?

user_14557680 0
Viewed 53

I am trying to import some data from a .csv file using a modified version of FileIO. I am supposed to use this data to show axis posture information. Therefore, values should be updated automatically every second. Then I created Q_PROPERTIES for every variable and created the code which gets data from the CSV file. I also added emit valueChanged() after every changing process.

void FileIO::getData()
{
    if (mSource.isEmpty()){
        emit error("source is empty");
    }
    QFile file(mSource);
    if (file.open(QIODevice::ReadOnly) ) {
        QString line;
        while (!file.atEnd()) {
            QByteArray line = file.readLine();
            xValue = line.split(',')[0].toFloat();
            emit xValueChanged();
            yValue = line.split(',')[3].toFloat();
            emit yValueChanged();
            zValue = line.split(',')[4].toFloat();
            emit zValueChanged();
            //Sleep(1000);
            qDebug()<< xValue <<yValue << zValue;
        }

        file.close();
    } else {
        emit error("Unable to open the file");
    }
}

So far, everything was fine but to spark the importing process I used Component.onCompleted.

    FileIO{
        id: dataCSV
        source: "C:/Users/Halil/yedekleme/Belgeler/build-serialGui-Desktop_Qt_5_14_2_MinGW_32_bit-Release/data.csv"
    }
    Component.onCompleted: {
        dataCSV.getData()
    }

...
            Entity
            {
                id: satEntity
                components: [
                    SceneLoader
                    {
                        id: sceneLoader
                        source:  "sat.stl"
                    },
                    Transform {
                        id:satTransform
                        rotationX: dataCSV.xValue
                        rotationY: dataCSV.yValue
                        rotationZ: dataCSV.zValue
                    }
                ]
            }

And the problem is I have to use these data to rotate a 3D object in real-time, but the engine doesn't load the ApplicationWindow before the Component.onCompleted is done. I see the values are updating -printing them to screen- but the transformer component cannot use them because the ApplicationWindow is not initialized before Component.onCompleted finishes, therefore I only see the last values.
last scene

qml qt c++
1 Answers

The problem is that the reading of the data is very fast so that our slow vision cannot see the change. In this case, what you should do is create a method that only reads a line and updates the value of xValue, yValue and zValue and then use a Timer to invoke that method every T seconds:

class FileIO: public QObject{
    Q_OBJECT
    Q_PROPERTY(QString source READ source WRITE setSource NOTIFY sourceChanged)
    Q_PROPERTY(qreal xValue READ xValue NOTIFY xValueChanged)
    Q_PROPERTY(qreal yValue READ xValue NOTIFY yValueChanged)
    Q_PROPERTY(qreal zValue READ xValue NOTIFY zValueChanged)
public:
    FileIO(QObject *parent=nullptr):
        QObject(parent), m_xValue(0.0), m_yValue(0.0), m_zValue(0.0), m_started(false)
    {
    }
    QString source() const
    {
        return m_file.fileName();
    }
    void setSource(QString source)
    {
        if (m_file.fileName() == source)
            return;
        m_file.setFileName(source);
        Q_EMIT sourceChanged();
    }
    qreal xValue() const
    {
        return m_xValue;
    }
    qreal yValue() const
    {
        return m_yValue;
    }
    qreal zValue() const
    {
        return m_zValue;
    }

    Q_INVOKABLE bool readNext(){
        tryStart();
        QString line;
        if(m_ts.readLineInto(&line)) {
            processLine(line);
            return true;
        }
        return false;
    }
Q_SIGNALS:
    void sourceChanged();

    void xValueChanged();
    void yValueChanged();
    void zValueChanged();
protected:
    void processLine(const QString & line){
        QStringList string_values = line.split(",");
        QVector<qreal> values(3);
        for(int i=0; i < values.size(); ++i){
            if(i < string_values.length()){
                values[i] = string_values[i].toDouble();
            }
        }
        m_xValue = values[0];
        m_yValue = values[1];
        m_zValue = values[2];
        Q_EMIT xValueChanged();
        Q_EMIT yValueChanged();
        Q_EMIT zValueChanged();
    }
private:
    bool tryStart(){
        if(m_started)
            return true;
        if(!m_file.open(QIODevice::ReadOnly)){
            qDebug() << m_file.errorString();
            m_ts.setDevice(nullptr);
            m_started = false;
            return false;
        }
        m_ts.setDevice(&m_file);
        m_started = true;
        return true;
    }
    QFile m_file;
    QTextStream m_ts;
    qreal m_xValue;
    qreal m_yValue;
    qreal m_zValue;
    bool m_started;
};

FileIO{
    id: dataCSV
    source: "C:/Users/Halil/yedekleme/Belgeler/build-serialGui-Desktop_Qt_5_14_2_MinGW_32_bit-Release/data.csv"
}
Timer{
    id: timer
    interval: 1000
    repeat: true
    onTriggered: {
        if(!dataCSV.readNext())
            dataCSV.stop()
    }
}
Component.onCompleted: timer.start()
user_66225870
Related