//Track.h
class Track
{
   Q_OBJECT
   public:
       Track(const std::string&);
       Track();
       ~Track();
       const std::string& getName() const;
       const sf::Music& getAudio() const;
   private:
       std::string name;
       sf::Music* audio;


   public slots:
       void playSong();
};

///PlayList.h
class PlayList : public QListWidget
{
    Q_OBJECT
public:
    PlayList(QWidget* parent = 0);
    void mouseDoubleClickEvent(QMouseEvent*);

signals:
    void clickedToPlay();
};


/// from MainWindow.h and cpp
std::vector<Track> playList;
QObject::connect(ui->tab1List,SIGNAL(clickedToPlay()),&playList[playList.size()-1],SLOT(play())); // from main window class