Media Player Example (ActiveQt)▲

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Media Player demonstrates how a Qt application can communicate with embedded ActiveX controls using signals, slots, and the dynamicCall() function.

 
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class MainWindow : public QMainWindow
{
    Q_OBJECT
public:
    MainWindow();
    ~MainWindow();
    void openMedia(const QString &mediaUrl);

public slots:
    void on_mediaPlayer_PlayStateChange(int newState);
    void on_actionOpen_triggered();
    void on_actionExit_triggered();
    void on_actionAbout_triggered();
    void on_actionAboutQt_triggered();

private:
    void updateWindowTitle(const QString &state);
    Ui::MainWindow m_ui;
};

The MainWindow class declares a QMainWindow based user interface, using the Ui::MainWindow class created by Qt Designer. A number of slots are implemented to handle events from user interface elements, including the mediaPlayer object, which is a QAxWidget hosting the Microsoft Media Player ActiveX control.

 
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MainWindow::MainWindow()
{
    m_ui.setupUi(this);

    QSettings settings(QSettings::IniFormat, QSettings::UserScope,
                       QCoreApplication::organizationName(), QCoreApplication::applicationName());

    const QByteArray restoredGeometry = settings.value(QLatin1String(geometryKey)).toByteArray();
    if (restoredGeometry.isEmpty() || !restoreGeometry(restoredGeometry)) {
        const QRect availableGeometry = QApplication::desktop()->availableGeometry(this);
        const QSize size = (availableGeometry.size() * 4) / 5;
        resize(size);
        move(availableGeometry.center() - QPoint(size.width(), size.height()) / 2);
    }

    m_ui.mediaPlayer->dynamicCall("enableContextMenu", false);
    m_ui.mediaPlayer->dynamicCall("stretchToFit", true);
    updateWindowTitle("");
}

The constructor initializes the user interface, restores a previously saved window geometry, and uses the dynamicCall() function to invoke the APIs implemented by the Microsoft Media Player ActiveX control, to set initial configuration parameters.

 
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void MainWindow::on_mediaPlayer_PlayStateChange(int newState)
{
    static const QHash<int, const char *> stateMapping {
        {1,  "Stopped"},
        {2,  "Paused"},
        {3,  "Playing"},
        {4,  "Scanning Forwards"},
        {5,  "Scanning Backwards"},
        {6,  "Buffering"},
        {7,  "Waiting"},
        {8,  "Media Ended"},
        {9,  "Transitioning"},
        {10, "Ready"},
        {11, "Reconnecting"},
    };
    const char *stateStr = stateMapping.value(newState, "");
    updateWindowTitle(tr(stateStr));
}

The on_mediaPlayer_PlayStateChange slot handles the signal emitted by the mediaPlayer