Qt Linux - Lesson 001. Autorun Qt application under Linux

Linux, Qt, автозапуск, autorun, Ubuntu

Let's talk about how you can add functionality in Qt application to configure startup of the application. For example, we have a settings window, and we want to make the ability to customize the dialog box Autorun application.

In contrast to the autorun in Windows , where you can use QSettings and make changes to the registry on Linux you need to create a custom executable file that will be responsible for autostart applications when a user logs into the operating system.

Say the name of the project and hence the name of the executable file will AutorunLinux , then you need to create an executable file AutorunLinux.desktop the following path:

~/.config/autostart/AutorunLinux.desktop

The contents of the executable file to do the same to other startup files of other applications that are guaranteed to get the desired result. In the case of Ubuntu Linux 15.04 / 15.10 contents of the file will receive the following:

[Desktop Entry]
Type=Application
Exec=/home/dekadent/QT/Projects/build-AutorunLinux-Desktop_Qt_5_5_1_GCC_64bit-Debug/AutorunLinux
Hidden=false
NoDisplay=false
X-GNOME-Autostart-enabled=true
Name[en_GB]=AutorunLinux
Name=AutorunLinux
Comment[en_GB]=AutorunLinux
Comment=AutorunLinux

Where Exec parameter specifies the path to the executable file.

Also, do not forget to make the file executable:

chmod +x ~/.config/autostart/AutorunLinux.desktop

To be guaranteed to ensure correct startup file contents being prepared, I recommend to start to add your application to autostart with a standard utility Startup Applications .

This utility will create a guaranteed working version of the file for your application. Then you just need to add content through the code with an automatic modification of the path to the executable file.

Project structure

To demonstrate the code, I suggest the following to create a project with the following contents:

• AutorunLinux.pro - the profile of the project;
• widget.h - header file of the main application window;
• widget.cpp - file source code of the main application window;
• widget.ui - form the main application window;
• main.cpp - the main file of the application source code.

This application will be a checkbox, as we will delete and add applications to the startup by pressing the PushButton button. When running the application will pop up a message that the application is running. The appearance of the application as follows:

widget.h

In the header file of all the changes will be only ad slot to press the button:

#ifndef WIDGET_H
#define WIDGET_H
 
#include <QWidget>
 
namespace Ui {
class Widget;
}
 
class Widget : public QWidget
{
    Q_OBJECT
 
public:
    explicit Widget(QWidget *parent = 0);
    ~Widget();
 
private slots:
    void on_pushButton_clicked();
 
private:
    Ui::Widget *ui;
};
 
#endif // WIDGET_H

widget.cpp

#include "widget.h"
#include "ui_widget.h"
#include <QMessageBox>
#include <QDir>
#include <QFile>
#include <QTextStream>
#include <QStandardPaths>
 
Widget::Widget(QWidget *parent) :
    QWidget(parent),
    ui(new Ui::Widget)
{
    ui->setupUi(this);
    QMessageBox::information(this,"AutoRun","Apllication is started!");
}
 
Widget::~Widget()
{
    delete ui;
}
 
void Widget::on_pushButton_clicked()
{
    // Path to the autorun folder
    QString autostartPath = QStandardPaths::standardLocations(QStandardPaths::ConfigLocation).at(0) + QLatin1String("/autostart");
    /* Check whether there is a directory in which to store the autorun file.
     * And then you never know ... user deleted ...
     * */
    QDir autorunDir(autostartPath);
    if(!autorunDir.exists()){
        // Если не существует, то создаём
        autorunDir.mkpath(autostartPath);
    }
    QFile autorunFile(autostartPath + QLatin1String("/AutorunLinux.desktop"));
    /* Check the state of the checkbox, if checked, adds the application to the startup.
     * Otherwise remove
     * */
    if(ui->checkBox->isChecked()) {
        // Next, check the availability of the startup file
        if(!autorunFile.exists()){
 
            /* Next, open the file and writes the necessary data
             * with the path to the executable file, using QCoreApplication::applicationFilePath()
             * */
            if(autorunFile.open(QFile::WriteOnly)){
 
                QString autorunContent("[Desktop Entry]\n"
                                       "Type=Application\n"
                                       "Exec=" + QCoreApplication::applicationFilePath() + "\n"
                                       "Hidden=false\n"
                                       "NoDisplay=false\n"
                                       "X-GNOME-Autostart-enabled=true\n"
                                       "Name[en_GB]=AutorunLinux\n"
                                       "Name=AutorunLinux\n"
                                       "Comment[en_GB]=AutorunLinux\n"
                                       "Comment=AutorunLinux\n");
                QTextStream outStream(&autorunFile);
                outStream << autorunContent;
                // Set access rights, including on the performance of the file, otherwise the autorun does not work
                autorunFile.setPermissions(QFileDevice::ExeUser|QFileDevice::ExeOwner|QFileDevice::ExeOther|QFileDevice::ExeGroup|
                                       QFileDevice::WriteUser|QFileDevice::ReadUser);
                autorunFile.close();
            }
        }
    } else {
        // Delete the startup file
        if(autorunFile.exists()) autorunFile.remove();
    }
}

Conclusion

As a result of the application of this code will make itself to the startup and run when a user logs into the system. To test performance, create an application using the autorun file, log out and log in again (Log Out/ Log In).

The source code of the project: AutorunLinux