qt音乐播放器一个按钮实现点一下播放音乐再点一下暂停播放

您可以使用QMediaPlayer类来实现这个功能。您需要创建一个QPushButton并将其连接到一个槽函数。在槽函数中，您可以使用QMediaPlayer的play()和pause()函数来播放和暂停音乐。您还需要跟踪当前的播放状态以便在按钮被点击时进行适当的操作。以下是一个示例代码：

#include <QtWidgets>

class MusicPlayer : public QWidget
{
    Q_OBJECT

public:
    MusicPlayer(QWidget *parent = nullptr);

private slots:
    void togglePlayback();

private:
    QPushButton *m_button;
    QMediaPlayer *m_player;
    QMediaPlaylist *m_playlist;
    QMediaPlaylist *m_playedPlaylist;

    enum PlaybackState { StoppedState, PlayingState, PausedState };
    PlaybackState m_state = StoppedState;
};

MusicPlayer::MusicPlayer(QWidget *parent)
    : QWidget(parent)
{
    // Create the button and connect it to the togglePlayback slot
    m_button = new QPushButton("Play", this);
    connect(m_button, &QPushButton::clicked, this, &MusicPlayer::togglePlayback);

    // Create the player and playlist
    m_player = new QMediaPlayer(this);
    m_playlist = new QMediaPlaylist(m_player);
    m_playedPlaylist = new QMediaPlaylist(m_player);

    // Add some songs to the playlist
    m_playlist->addMedia(QUrl("qrc:/music/song1.mp3"));
    m_playlist->addMedia(QUrl("qrc:/music/song2.mp3"));
    m_playlist->addMedia(QUrl("qrc:/music/song3.mp3"));

    // Set the playlist to loop
    m_playlist->setPlaybackMode(QMediaPlaylist::Loop);

    // Set the player's playlist
    m_player->setPlaylist(m_playlist);
}

void MusicPlayer::togglePlayback()
{
    switch (m_state) {
    case StoppedState:
        m_player->play();
        m_state = PlayingState;
        m_button->setText("Pause");
        break;
    case PlayingState:
        m_player->pause();
        m_state = PausedState;
        m_playedPlaylist->addMedia(m_player->currentMedia());
        m_button->setText("Play");
        break;
    case PausedState:
        m_player->play();
        m_state = PlayingState;
        m_button->setText("Pause");
        break;
    }
}

int main(int argc, char *argv[])
{
    QApplication app(argc, argv);

    // Load the music files from resources
    Q_INIT_RESOURCE(music);

    MusicPlayer player;
    player.show();

    return app.exec();
}

#include "main.moc"

在这个示例中，我们创建了一个名为MusicPlayer的窗口小部件，并在其中添加了一个QPushButton。我们还创建了一个QMediaPlayer和两个QMediaPlaylist，一个用于播放列表，另一个用于存储已播放的媒体。在槽函数togglePlayback()中，我们根据当前的播放状态来决定是播放还是暂停音乐，并更新按钮的文本。当用户点击按钮时，该函数将被调用。