音樂播放器

Screenshot of the Music Player example

音樂播放器範例演示如何使用各種提供特徵通過 QtWinExtras 模塊。

注意： The example uses QMediaPlayer 從 QtMultimedia module to play the music, but this article focuses on the parts where QtWinExtras 特徵的使用。

DWM 特徵

範例使用 Windows DWM (桌麵窗口管理器) 特徵以將窗口內容視覺集成到窗口框架，並使主窗口、音量彈齣窗口半透明和模糊。

範例基於是否啓用閤成，應用不同外觀。當閤成被啓用時，主窗口變半透明且窗口框架會擴展到客戶端區域，以使窗口內容無縫集成到窗口框架，如上所示。當閤成被禁用時，將著色顔色用作背景顔色。以下屏幕截圖闡明 Music Player 範例外觀如何當閤成被禁用時。

Screenshot of the Music Player example

各自代碼組閤擴展或重置係統框架，調節必要 QWidget 屬性，並設置適當樣式錶以達成期望外觀。

void MusicPlayer::stylize()
{
    if (QtWin::isCompositionEnabled()) {
        QtWin::extendFrameIntoClientArea(this, -1, -1, -1, -1);
        setAttribute(Qt::WA_TranslucentBackground, true);
        setAttribute(Qt::WA_NoSystemBackground, false);
        setStyleSheet(QStringLiteral("MusicPlayer { background: transparent; }"));
    } else {
        QtWin::resetExtendedFrame(this);
        setAttribute(Qt::WA_TranslucentBackground, false);
        setStyleSheet(QStringLiteral("MusicPlayer { background: %1; }").arg(QtWin::realColorizationColor().name()));
    }
    volumeButton->stylize();
}

音量彈齣窗口沒有窗口框架，因此足以模糊彈齣窗口當啓用閤成時。此外，應用樣式錶能獲得遵循著色顔色的邊框。就像主窗口，當禁用閤成時，著色顔色將用作背景顔色。

void VolumeButton::stylize()
{
    if (QtWin::isCompositionEnabled()) {
        QtWin::enableBlurBehindWindow(menu);
        QString css("QMenu { border: 1px solid %1; border-radius: 2px; background: transparent; }");
        menu->setStyleSheet(css.arg(QtWin::realColorizationColor().name()));
    } else {
        QtWin::disableBlurBehindWindow(menu);
        QString css("QMenu { border: 1px solid black; background: %1; }");
        menu->setStyleSheet(css.arg(QtWin::realColorizationColor().name()));
    }
}

The example application respects the user's composition settings, reacts to dynamic composition changes, and looks solid regardless of whether composition is enabled or not. It accomplishes this by catching QWinEvent::CompositionChange and QWinEvent::ColorizationChange events and adjusting its looks accordingly.

bool MusicPlayer::event(QEvent *event)
{
    if (event->type() == QWinEvent::CompositionChange || event->type() == QWinEvent::ColorizationChange)
        stylize();
    return QWidget::event(event);
}

跳轉列錶

範例創建自定義跳轉列錶，為用戶提供對最近播放音樂文件的快速訪問。

void MusicPlayer::createJumpList()
{
    QWinJumpList jumplist;
    jumplist.recent()->setVisible(true);
}

要啓用應用程序跳轉列錶以展示期望的最近文件，使用以下幫手函數注冊相應文件類型。

static bool associateFileTypes()
{
    QString displayName = QGuiApplication::applicationDisplayName();
    QString filePath = QCoreApplication::applicationFilePath();
    QString fileName = QFileInfo(filePath).fileName();
    const QString key = QStringLiteral("HKEY_CURRENT_USER\\Software\\Classes\\Applications\\") + fileName;
    QSettings settings(key, QSettings::NativeFormat);
    if (settings.status() != QSettings::NoError) {
        qWarning() << "Cannot access registry key" << key;
        return false;
    }
    settings.setValue(QStringLiteral("FriendlyAppName"), displayName);
    settings.beginGroup(QStringLiteral("SupportedTypes"));
    QMimeDatabase mimeDatabase;
    const QStringList supportedMimeTypes = MusicPlayer::supportedMimeTypes();
    for (const QString &fileType : supportedMimeTypes) {
        const QStringList suffixes = mimeDatabase.mimeTypeForName(fileType).suffixes();
        for (QString suffix : suffixes) {
            suffix.prepend('.');
            settings.setValue(suffix, QString());
        }
    }
    settings.endGroup();
    settings.beginGroup(QStringLiteral("shell"));
    settings.beginGroup(QStringLiteral("open"));
    settings.setValue(QStringLiteral("FriendlyAppName"), displayName);
    settings.beginGroup(QStringLiteral("Command"));
    settings.setValue(QStringLiteral("."),
                      QLatin1Char('"') + QDir::toNativeSeparators(filePath) + QStringLiteral("\" \"%1\""));
    return true;
}

任務欄疊加和進度

範例使用 Windows 任務欄為 2 件事；設置錶示當前音樂迴放狀態的疊加圖標，和在任務欄按鈕指示迴放進度。

Screenshot of the Music Player taskbar

The following snippet shows how the taskbar button is prepared. The playback progress is wired directly to the taskbar progress indicator by using signals and slots.

void MusicPlayer::createTaskbar()
{
    taskbarButton = new QWinTaskbarButton(this);
    taskbarButton->setWindow(windowHandle());
    taskbarProgress = taskbarButton->progress();
    connect(positionSlider, &QAbstractSlider::valueChanged, taskbarProgress, &QWinTaskbarProgress::setValue);
    connect(positionSlider, &QAbstractSlider::rangeChanged, taskbarProgress, &QWinTaskbarProgress::setRange);
    connect(&mediaPlayer, &QMediaPlayer::stateChanged, this, &MusicPlayer::updateTaskbar);
}

會更新疊加圖標和進度指示器，每當音樂迴放狀態改變時。

void MusicPlayer::updateTaskbar()
{
    switch (mediaPlayer.state()) {
    case QMediaPlayer::PlayingState:
        taskbarButton->setOverlayIcon(style()->standardIcon(QStyle::SP_MediaPlay));
        taskbarProgress->show();
        taskbarProgress->resume();
        break;
    case QMediaPlayer::PausedState:
        taskbarButton->setOverlayIcon(style()->standardIcon(QStyle::SP_MediaPause));
        taskbarProgress->show();
        taskbarProgress->pause();
        break;
    case QMediaPlayer::StoppedState:
        taskbarButton->setOverlayIcon(style()->standardIcon(QStyle::SP_MediaStop));
        taskbarProgress->hide();
        break;
    }
}

Windows 縮略圖工具欄用於提供基本音樂迴放控件。這些控件可用於控製應用程序，不必激活應用程序。

void MusicPlayer::createThumbnailToolBar()
{
    thumbnailToolBar = new QWinThumbnailToolBar(this);
    thumbnailToolBar->setWindow(windowHandle());
    playToolButton = new QWinThumbnailToolButton(thumbnailToolBar);
    playToolButton->setEnabled(false);
    playToolButton->setToolTip(tr("Play"));
    playToolButton->setIcon(style()->standardIcon(QStyle::SP_MediaPlay));
    connect(playToolButton, &QWinThumbnailToolButton::clicked, this, &MusicPlayer::togglePlayback);
    forwardToolButton = new QWinThumbnailToolButton(thumbnailToolBar);
    forwardToolButton->setEnabled(false);
    forwardToolButton->setToolTip(tr("Fast forward"));
    forwardToolButton->setIcon(style()->standardIcon(QStyle::SP_MediaSeekForward));
    connect(forwardToolButton, &QWinThumbnailToolButton::clicked, this, &MusicPlayer::seekForward);
    backwardToolButton = new QWinThumbnailToolButton(thumbnailToolBar);
    backwardToolButton->setEnabled(false);
    backwardToolButton->setToolTip(tr("Rewind"));
    backwardToolButton->setIcon(style()->standardIcon(QStyle::SP_MediaSeekBackward));
    connect(backwardToolButton, &QWinThumbnailToolButton::clicked, this, &MusicPlayer::seekBackward);
    thumbnailToolBar->addButton(backwardToolButton);
    thumbnailToolBar->addButton(playToolButton);
    thumbnailToolBar->addButton(forwardToolButton);
    connect(&mediaPlayer, &QMediaPlayer::positionChanged, this, &MusicPlayer::updateThumbnailToolBar);
    connect(&mediaPlayer, &QMediaPlayer::durationChanged, this, &MusicPlayer::updateThumbnailToolBar);
    connect(&mediaPlayer, &QMediaPlayer::stateChanged, this, &MusicPlayer::updateThumbnailToolBar);
}

會相應更新縮略圖工具欄按鈕，每當音樂迴放狀態改變時。

void MusicPlayer::updateThumbnailToolBar()
{
    playToolButton->setEnabled(mediaPlayer.duration() > 0);
    backwardToolButton->setEnabled(mediaPlayer.position() > 0);
    forwardToolButton->setEnabled(mediaPlayer.position() < mediaPlayer.duration());
    if (mediaPlayer.state() == QMediaPlayer::PlayingState) {
        playToolButton->setToolTip(tr("Pause"));
        playToolButton->setIcon(style()->standardIcon(QStyle::SP_MediaPause));
    } else {
        playToolButton->setToolTip(tr("Play"));
        playToolButton->setIcon(style()->standardIcon(QStyle::SP_MediaPlay));
    }
}

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