I really need some help updating my QTreeView. I have been looking all over the forum for solutions but I couldn't find any that worked...

This is the code I got:
Qt Code: 
  1. PlaylistModel* plm = NULL;
  2.  
  3. MainWindow::MainWindow()
  4. {
  5. 	setupUi(this);
  6. 	plm = new PlaylistModel(this);
  7. 	treeView->setModel(plm);
  8. }
To copy to clipboard, switch view to plain text mode 
Qt Code: 
  1. extern Playlist* currentPlaylist;
  2.  
  3. QVariant PlaylistModel::data(const QModelIndex &index, int role) const
  4. {
  5. 	if(!index.isValid())
  6. 		return QVariant();
  7. 	if(index.row() >= currentPlaylist->size())
  8. 		return QVariant();
  9. 	if(role == Qt::DisplayRole)
  10. 	{
  11. 		Song* song = currentPlaylist->at(index.row());
  12. 		if(song)
  13. 		{
  14. 			std::cout << "Song found!" << std::endl;
  15. 			if(song->info)
  16. 			{
  17. 				std::cout << "Info found!" << std::endl;
  18. 				if(index.column() == 0)
  19. 					return "Title";
  20. 				else if(index.column() == 1)
  21. 					return "Artist";
  22. 			}
  23. 		}
  24. 		return "N/A";
  25. 	}
  26. 	else
  27. 		return QVariant();
  28. }
  29.  
  30. QVariant PlaylistModel::headerData(int section, Qt::Orientation orientation, int role) const
  31. {
  32. 	if(role != Qt::DisplayRole)
  33. 		return QVariant();
  34. 	if(orientation == Qt::Horizontal)
  35. 		return QString("Column %1").arg(section);
  36. 	else
  37. 		return QString("Row %1").arg(section);
  38. }
  39.  
  40. int PlaylistModel::rowCount(const QModelIndex &parent) const
  41. {
  42. 	return currentPlaylist->size();
  43. }
  44.  
  45. int PlaylistModel::columnCount(const QModelIndex &parent) const
  46. {
  47. 	return 2;
  48. }
  49.  
  50. void PlaylistModel::update()
  51. {
  52. 	QModelIndex topLeft = createIndex(0, 0);
  53. 	QModelIndex bottomRight = createIndex(currentPlaylist->size()-1, 1);
  54. 	dataChanged(topLeft, bottomRight);
  55. }
To copy to clipboard, switch view to plain text mode 

As you can see, the data is stored in currentPlaylist (the Playlist class is just a QList). But when I add data to the currentPlaylist, it doesn't show it on the treeView... But when I add data to the currentPlaylist before I construct the tableView and model, it does show the data!

So I have tried to make an update function. But that doesn't work either...

Thanks in advance,
Gillis