MessageWindow.cpp Example File

    /**
     * @file MessageWindow.cpp
     * @brief MessageWindow Implementation.
     * @see MessageWindow.h
     * @author Micha? Policht
     */

    #include <stdio.h>
    #include "MessageWindow.h"
    #include <QMessageBox>
    #include <QCoreApplication>
    #include <QMutexLocker>

    const char *MessageWindow::WINDOW_TITLE = "Message Window";
    MessageWindow *MessageWindow::MsgHandler = NULL;

    MessageWindow::MessageWindow(QWidget *parent, Qt::WindowFlags flags)
        : QDockWidget(parent, flags),
          msgTextEdit(this)
    {
        setWindowTitle(tr(WINDOW_TITLE));
        msgTextEdit.setReadOnly(true);
        setWidget(&msgTextEdit);

        MessageWindow::MsgHandler = this;
    }

    //static
    QString MessageWindow::QtMsgToQString(QtMsgType type, const char *msg)
    {
        switch (type) {
        case QtDebugMsg:
            return QLatin1String("Debug: ")+QLatin1String(msg);
        case QtWarningMsg:
            return QLatin1String("Warning: ")+QLatin1String(msg);
        case QtCriticalMsg:
            return QLatin1String("Critical: ")+QLatin1String(msg);
        case QtFatalMsg:
            return QLatin1String("Fatal: ")+QLatin1String(msg);
        default:
            return QLatin1String("Unrecognized message type: ")+QLatin1String(msg);
        }
    }

    //static
    void MessageWindow::AppendMsgWrapper(QtMsgType type, const char *msg)
    {
        static QMutex mutex;
        QMutexLocker locker(&mutex);

        if (MessageWindow::MsgHandler != NULL)
            return MessageWindow::MsgHandler->postMsgEvent(type, msg);
        else
            fprintf(stderr, "%s", MessageWindow::QtMsgToQString(type, msg).toLatin1().data());
    }

    #if QT_VERSION >= QT_VERSION_CHECK(5,0,0)
    void MessageWindow::AppendMsgWrapper(QtMsgType type, const QMessageLogContext & /*context*/, const QString &msg)
    {
        AppendMsgWrapper(type, msg.toLatin1().data());
    }
    #endif

    void MessageWindow::customEvent(QEvent *event)
    {
        if (static_cast<MessageWindow::EventType>(event->type()) == MessageWindow::MessageEventType)
            msgTextEdit.append(dynamic_cast<MessageEvent *>(event)->msg);
    }

    void MessageWindow::postMsgEvent(QtMsgType type, const char *msg)
    {
        QString qmsg = MessageWindow::QtMsgToQString(type, msg);
        switch (type) {
        case QtDebugMsg:
            break;
        case QtWarningMsg:
            qmsg.prepend(QLatin1String("<FONT color=\"#FF0000\">"));
            qmsg.append(QLatin1String("</FONT>"));
            break;
        case QtCriticalMsg:
            if (QMessageBox::critical(this, QLatin1String("Critical Error"), qmsg,
                                      QMessageBox::Ignore,
                                      QMessageBox::Abort,
                                      QMessageBox::NoButton) == QMessageBox::Abort)
                abort(); // core dump
            qmsg.prepend(QLatin1String("<B><FONT color=\"#FF0000\">"));
            qmsg.append(QLatin1String("</FONT></B>"));
            break;
        case QtFatalMsg:
            QMessageBox::critical(this, QLatin1String("Fatal Error"), qmsg, QMessageBox::Ok, QMessageBox::NoButton, QMessageBox::NoButton);
            abort(); // deliberately core dump
        }
        //it's impossible to change GUI directly from thread other than the main thread
        //so post message encapsulated by MessageEvent to the main thread's event queue
        QCoreApplication::postEvent(this, new MessageEvent(qmsg));
    }

    MessageEvent::MessageEvent(QString &msg):
        QEvent(static_cast<QEvent::Type>(MessageWindow::MessageEventType))
    {
        this->msg = msg;
    }