How to run SequentialAnimation in the background?

bintuch

I'm designing Qt5.7/QML application. The main idea is that pressing a button will trigger shell command which takes long time. The results of this command should be reflected in widgets.
In the meantime, I need SequentialAnimation to run, to show the user that something is happening in the background. So I start the animation and then call the process which sends the shell command.
But the animation seems to be freezed as the entire GUI until the shell command returns.
I'm a new comer to Qt/QML/C++ (hardware engineer...).
Any suggestions? Can you please post the code for the QML/C++/new header?
QML Code:

CircularGauge {
    id: speedometer_wr
    x: 199
    y: 158
    value: valueSource.bps
    maximumValue: 400
    width: height
    height: container.height * 0.5
    stepSize: 0
    anchors {
        verticalCenter: parent.verticalCenter
        verticalCenterOffset: 46
    }
    style: DashboardGaugeStyle {}

    NumberAnimation {
        id: animation_wr
        running: false
        target: speedometer_wr
        property: "value"
        easing.type: Easing.InOutSine
        from: 0
        to: 300
        duration: 15000
    }
}

Button {
    id: button_benchmark
    x: 168
    y: 26
    width: 114
    height: 47
    text: qsTr("Benchmark")
    tooltip: "Execute the performance test"
    checkable: true
    function handle_becnhmark() {
        speedometer_wr.value = 0;

        // Uncheck the button
        button_benchmark.checked = false;

        // Start the animation
        animation_wr.start();

        // Run the benchmark
        var res = backend.run_benchmark();

        // Stop the animation
        animation_wr.stop();

        speedometer_wr.value = parseFloat(res.split(",")[0]);
    }
    onClicked: {handle_becnhmark()}
}

Cpp Code:

#include <QProcess>
#include <QtDebug>
#include "backend.h"
#include <QRegExp>

BackEnd::BackEnd(QObject *parent) : QObject(parent)
{

}

QString BackEnd::run_benchmark() {
    qDebug() << "in run_benchmark";
    QProcess proc;

    // Execute shell command
    proc.start(<LONG_SHELL_COMMAND>);
    if (!proc.waitForStarted())
        return "";
    if (!proc.waitForFinished())
        return "";

    // Get the results, parse and return values
     QString result(proc.readAll());
    return result;
}

backend.h:

#ifndef BACKEND_H
#define BACKEND_H

#include <QObject>

class BackEnd : public QObject
{
    Q_OBJECT

public:
    explicit BackEnd(QObject *parent = nullptr);

signals:

public slots:
    QString run_benchmark();
};

#endif // BACKEND_H

Tirupathi Korla

@bintuch
You may run the process in a thread.

bintuch

@Tirupathi-Korla . How to do it? Can you please post example code how to wrap the process as a thread?

Tirupathi Korla

@bintuch
When you want to run a process, use some thing like
QtConcurrent::run(this, & BackEnd::startaProcess);

and in BackEnd, write

void startaProcess(){
   // start a process here..
}

Go through http://doc.qt.io/qt-5/qtconcurrentrun.html#using-member-functions for Qtconcurrent docs.