在菜单中执行任何操作后，Qt Tray应用程序将自行关闭

我是QT新手，遇到了问题。

我决定尝试使用Qt和QSystemTrayIcon编写一个小型应用程序。首先，我决定从Qt的官方网站复制该示例。

https://doc.qt.io/qt-5/qtwidgets-desktop-systray-example.html？

这是我的头文件：

#ifndef MAINWINDOW_H
#define MAINWINDOW_H

#include <QMainWindow>
#include <QSystemTrayIcon>

namespace Ui {
    class MainWindow;
}

class MainWindow : public QMainWindow
{
    Q_OBJECT

 public:
    explicit MainWindow(QWidget *parent = nullptr);
    ~MainWindow();

private:
    Ui::MainWindow *ui;
    QMenu *trayIconMenu;
    QAction *launchAction;
    QAction *quitAction;
    QSystemTrayIcon *trayIcon;

public slots:
    void changeEvent(QEvent*);
    void trayIconActivated(QSystemTrayIcon::ActivationReason reason);
    void trayActionExecute();
    void setTrayIconActions();
    void showTrayIcon();
};

#endif // MAINWINDOW_H

这是我的源代码文件：

#include "mainwindow.h"
#include "ui_mainwindow.h"
#include <QMessageBox>

MainWindow::MainWindow(QWidget *parent) :
    QMainWindow(parent),
    ui(new Ui::MainWindow)
{
    ui->setupUi(this);
    this->setTrayIconActions();
    this->showTrayIcon();
}

MainWindow::~MainWindow()
{
    delete ui;
}

void MainWindow::showTrayIcon() {
    trayIcon = new QSystemTrayIcon(this);
    QIcon trayImage(":/images/trayIcon.png");
    trayIcon->setIcon(trayImage);
    trayIcon->setContextMenu(trayIconMenu);

    connect(trayIcon, 
         SLOT(activated(QSystemTrayIcon::ActivationReason)),
         this, 
         SLOT(trayIconActivated(QSystemTrayIcon::ActivationReason)));

    trayIcon->show();
}

void MainWindow::trayActionExecute() {
    QMessageBox::information(this, "TrayIcon", "Info text");
}

void MainWindow::trayIconActivated(QSystemTrayIcon::ActivationReason 
            reason) {

    switch (reason) {
        case QSystemTrayIcon::Trigger:
        case QSystemTrayIcon::DoubleClick:
            this->trayActionExecute();
            break;
        default:
            break;
    }
}

void MainWindow::showMsg() {
    QMessageBox::information(this, "Tray message", "Hello world!");
}

void MainWindow::setTrayIconActions() {
    launchAction = new QAction("Launch", this);
    quitAction = new QAction("Exit", this);

    connect (launchAction, SIGNAL(triggered()), this, SLOT(showMsg()));
    connect (quitAction, SIGNAL(triggered()), qApp, SLOT(quit()));

    // Setting system tray's icon menu
    trayIconMenu = new QMenu(this);
    trayIconMenu -> addAction (launchAction);
    trayIconMenu -> addAction (quitAction);
}

void MainWindow::changeEvent(QEvent *event) {
    QMainWindow::changeEvent(event);
    if (event->type() == QEvent::WindowStateChange) {
        if (isMinimized()) {
            this->hide();
        }
    }
 }

当我在上下文菜单中执行任何操作时，该应用程序仅关闭。我认为关键是要重写方法QCloseEvent，这将解决这种情况。所以，我重新实现它：

void MainWindow::closeEvent(QCloseEvent *event) {
    #ifdef Q_OS_OSX
    if (!event->spontaneous() || !isVisible()) {
        return;
    }
    #endif
    if (trayIcon->isVisible()) {
        QMessageBox::information(this, tr("Systray"),
                             tr("The program will keep running in the "
                                "system tray"));
        hide();
        event->ignore();
    }
}

有什么事吗

谢谢。