How to restart an application by pressing a button?

closx

Hello all,
As I described on the header, I want the application restarted (or rebooted I can say) when a button is clicked.
Example button:

Rectangle
                    {
                        id:helloButton
                        width:80
                        height:80
                        color: "transparent"
                        Image{
                            id:hellobg
                            source:"qrc:/hellobg.png"
                            sourceSize.height: 80
                            height: 80
                            fillMode: Image.PreserveAspectFit
                            antialiasing: true
                            smooth: true
                            opacity:1
                                MouseArea{
                                anchors.fill: parent
                                onClicked: {
                                    hello3bg.opacity = 0.2
                                    hello2bg.opacity = 0.2
                                    hellobg.opacity = 1

                               //////////  SOME CODE HERE TO RESTART
                               //////////  THE APPLICATION FOR ME


                                    }
                                }
                            }
                    }

ODБOï

@closx hi
qApp->quit();
QProcess::startDetached(qApp->arguments()[0], qApp->arguments());

but this is c++, so expose it to your qml if you need

closx

@LeLev Hi and thanks for your answer!
Actually I did not know that I am not able to do it on QML. So I should look around for how can I expose a C++ function into QML right? I also want to change opacities of some buttons if some conditions exits, or some signals are triggered. I was trying to do something like that,

Image{
                            id:chinese
                            source:"qrc:/design/settings/chinese.png"
                            sourceSize.height: 80
                            height:80
                            fillMode: Image.PreserveAspectFit
                            antialiasing: true
                            smooth: true
                            opacity: 0.2
                            if(SM.Lang == MyLang.CH)
                            {
                            opacity:1
                            }
                            MouseArea{
                            anchors.fill: parent
                            onClicked: {
                                SM.lang = MyLang.CH
                                chinese.opacity = 1
                                turkish.opacity = 0.2
                                english.opacity = 0.2
                                }
                            }
                            }

But it gave error on line I wrote the 'if' statement,

Unexpected token 'if'.
Expected a qualified name id.

J.Hilk

hi @closx replace

opacity: 0.2
if(SM.Lang == MyLang.CH)
{
opacity:1
}

with

opacity: SM.Lang == MyLang.CH ? 1 : 0.2

closx

@J.Hilk Hey, Thanks for your answer!
Your patch "kind of" solved the problem. Error was gone, but opacities won't change by language on restart. When I kept trying, I saw that problem is deeper. Probably something about my initial settings and translator defaults.
Thanks anyway!

closx

So everyone, I create a new header and source named "Restarter".
restarter.h

#ifndef RESTARTER_H
#define RESTARTER_H

#include <QObject>


class Restarter : public QObject
{
    Q_OBJECT

public:
    explicit Restarter(QObject *parent = nullptr);
    Q_INVOKABLE void makeRestart();

signals:

public slots:
};

#endif // RESTARTER_H

restarter.cpp (wrote a test function)

#include "restarter.h"
#include <QMessageBox>

Restarter::Restarter(QObject *parent) :
    QObject (parent)
{
}

void Restarter::makeRestart()
{
    QMessageBox msg;
    msg.setText("Hello world");
    msg.exec();
}

in main.cpp somewhere

#include "restarter.h"
    qmlRegisterType<Restarter>("closx.restarter", 1, 0, "Restarter");

and in my qml file somewhere

import closx.restarter 1.0
Restarter {
        id:restarter
    }
Image{
                            id:turkish
                            source:"qrc:/design/settings/turkish.png"
                            sourceSize.height: 80
                            height: 80
                            fillMode: Image.PreserveAspectFit
                            antialiasing: true
                            smooth: true
                            opacity:0.2
                                MouseArea{
                                anchors.fill: parent
                                onClicked: {
                                    SM.lang = MyLang.TR
                                    chinese.opacity = 0.2
                                    english.opacity = 0.2
                                    turkish.opacity = 1
                                    restarter.makeRestart
                                    }
                                }
                            }

Message box wont appear. What am I doing wrong?

J.Hilk

@closx said in How to restart an application by pressing a button?:

restarter.makeRestart

makeRestart is a function - you should get a warning in your console output regarding this

restarter.makeRestart()

closx

@J.Hilk OH! How can I be that stupid :D Thanks for the answer! Function is working now.
Btw, when I try to execute a QMessageBox in a QML app, the app is crashed...

J.Hilk

@closx
creating Ui components based on QWidgets from QML is not really supported (the other way around it is)

You probably have the wrong QApplication type, missing modules in the pro file or something along that line.

I would suggest sticking to QML-ui if your App is based around that.
You can take a look at KDAB's declarative-widgets if your interested in it

closx

@J.Hilk Hey, Thank you for all of your help. Solved the problem thanks to you!

If there is anyone facing the same issue, solved like this,
Created a source file named "restarter"
restarter.h

#ifndef RESTARTER_H
#define RESTARTER_H

#include <QObject>


class Restarter : public QObject
{
    Q_OBJECT

public:
    explicit Restarter(QObject *parent = nullptr);
    Q_INVOKABLE void makeRestart();

signals:

public slots:
};

#endif // RESTARTER_H

restarter.cpp (note: my application works as a service named "myservice" on system, so I can not restart it as restarting a regular application.)

#include "restarter.h"
#include <QProcess>


Restarter::Restarter(QObject *parent) :
    QObject (parent)
{
}

void Restarter::makeRestart()
{
    QProcess::execute("sudo service myservice restart");
}

If your application works NOT AS A SERVICE, BUT AN APPLICATION,
restarter.cpp

#include "restarter.h"
#include <QApplication>
#include <QProcess>


Restarter::Restarter(QObject *parent) :
    QObject (parent)
{
}

void Restarter::makeRestart()
{
qApp->quit();
 QProcess::startDetached(qApp->arguments()[0], qApp->arguments()); //application restart
}

You need to register "restarter.cpp" as a QML registery (I know, stupid sentence)
So you need to insert these lines in main.cpp

#include "restarter.h"
qmlRegisterType<Restarter>("closx.restarter", 1, 0, "Restarter");

and use it on your QML file:

import closx.restarter 1.0
Restarter {
        id:restarter
    }

                           Rectangle{
                               id: restartbg
                               width: 120
                               height: 70
                               radius: 8
                               color:"black"
                               anchors.centerIn: parent
                               z:344
                               Text{
                                   anchors.centerIn: parent
                                   text:qsTr("Restart") + mytrans.emptyString
                                   font.family:GSystem.myriadproita.name
                                   font.pixelSize: 18
                                   color: "white"
                               }
                               MouseArea{
                                   anchors.fill: parent
                                   onClicked: {
                                       restarter.makeRestart()
                                   }
                                   onPressed: {
                                       restartbg.color = "#1c1c1c"
                                   }
                                   onReleased: {
                                       restartbg.color = "black"
                                   }
                               }
                           }

Again, thanks to @LeLev and @J-Hilk for everything.