Creating QTableView dynamically / Creating new playlists

[SGaist]

@hbatalha said in Creating QTableView dynamically / Creating new playlists:

void PlaylistDock::on_addButton_clicked()
{
Mlt::Playlist* playlist = new Mlt::Playlist;

m_playlists.append(playlist);

ui->comboBox->addItem("Playlist " + QString::number(i++));

}

You are creating a new empty playlist so that's normal that your model is empty after you set.

[hbatalha]

@hbatalha said in Creating QTableView dynamically / Creating new playlists:

void PlaylistDock::on_comboBox_currentIndexChanged(int)
{
m_model.setPlaylist(*m_playlists.at(ui->comboBox->currentIndex()));
}

@SGaist

You are creating a new empty playlist

I mean when I switch playlist.

[JonB]

@hbatalha
As I wrote earlier, you need to use QAbstractItemModel::beginResetModel() when you change models. See e.g. https://stackoverflow.com/questions/14756645/how-to-reset-model-in-qt.

[hbatalha]

@JonB said in Creating QTableView dynamically / Creating new playlists:

@hbatalha
As I wrote earlier, you need to use QAbstractItemModel::beginResetModel() when you change models. See e.g. https://stackoverflow.com/questions/14756645/how-to-reset-model-in-qt.

The playlist model inherits from QAbstractTableModel as shown in the code above

[JonB]

@hbatalha
Yes, and what does that inherit from...?

[hbatalha]

@JonB
IbeginResetModel is protected. https://doc.qt.io/qt-5/qabstractitemmodel.html#beginResetModel

[JonB]

@hbatalha said in Creating QTableView dynamically / Creating new playlists:

beginResetModel is protected. https://doc.qt.io/qt-5/qabstractitemmodel.html#beginResetModel

You wrote earlier

The playlist model inherits from QAbstractTableModel as shown in the code above

So that means you can call protected methods, doesn't it?

If you have some aversion to resetting the model, you can probably delete all existing rows and insert all new rows if you really wish.

[hbatalha]

@JonB said in Creating QTableView dynamically / Creating new playlists:

So that means you can call protected methods, doesn't it?

That is what I expected, I am finding strange that the compiler is complaining that it is protected.

[JonB]

@hbatalha
If you are trying to go

m_model.beginResetModel();
m_model.setPlaylist(*m_playlists.at(ui->comboBox->currentIndex()));
m_model.endResetModel();

you cannot do that on protected methods. You must call them in PlaylistModel::setPlaylist().

[hbatalha]

@JonB said in Creating QTableView dynamically / Creating new playlists:

you cannot do that on protected methods. You must call them in PlaylistModel::setPlaylist().

yeah I fixed that.

But still, the playlist will be empty when I switch. I must be missing something.

[SGaist]

Where/when are you putting stuff in that playlist ?
You only show that you created it but at no point you seem to put anything in it.

[hbatalha]

@SGaist There is a drop event where the files added to the playlist will be at the same time added to the playlist vector current element (m_playlists.at(ui->comboBox->currentIndex())).

But I since discovered that the Mlt::Playlist doesn't allow copying. When I set a playlist (m_model.setPlaylist(*m_playlists.at(ui->comboBox->currentIndex())); ) the m_model.playlist() takes omership of all the elements in the playlist and when I switch to another playlist they get deleted. Here is the Mlt::Playlist interface:

class MLTPP_DECLSPEC Playlist : public Producer
	{
		private:
			mlt_playlist instance;
		public:
			Playlist( );
			Playlist( Profile& profile );
			Playlist( Service &playlist );
			Playlist( Playlist &playlist );
			Playlist( mlt_playlist playlist );
			virtual ~Playlist( );
			virtual mlt_playlist get_playlist( );
			mlt_producer get_producer( );
			int count( );
			int clear( );
			int append( Producer &producer, int in = -1, int out = -1 );
			int blank( int out );
			int blank( const char *length );
			int clip( mlt_whence whence, int index );
			int current_clip( );
			Producer *current( );
			ClipInfo *clip_info( int index, ClipInfo *info = NULL );
			static void delete_clip_info( ClipInfo *info );
			int insert( Producer &producer, int where, int in = -1, int out = -1 );
			int remove( int where );
			int move( int from, int to );
			int reorder( const int *indices );
			int resize_clip( int clip, int in, int out );
			int split( int clip, int position );
			int split_at( int position, bool left = true );
			int join( int clip, int count = 1, int merge = 1 );
			int mix( int clip, int length, Transition *transition = NULL );
			int mix_in( int clip, int length );
			int mix_out( int clip, int length );
			int mix_add( int clip, Transition *transition );
			int repeat( int clip, int count );
			Producer *get_clip( int clip );
			Producer *get_clip_at( int position );
			int get_clip_index_at( int position );
			bool is_mix( int clip );
			bool is_blank( int clip );
			bool is_blank_at( int position );
			void consolidate_blanks( int keep_length = 0 );
			Producer *replace_with_blank( int clip );
			void insert_blank( int clip, int out );
			void pad_blanks( int position, int length, int find = 0 );
			int insert_at( int position, Producer *producer, int mode = 0 );
			int insert_at( int position, Producer &producer, int mode = 0 );
			int clip_start( int clip );
			int clip_length( int clip );
			int blanks_from( int clip, int bounded = 0 );
			int remove_region( int position, int length );
	};

And here is the PlaylistModel::setPlaylist:

void PlaylistModel::setPlaylist(Mlt::Playlist& playlist)
{
    if (playlist.is_valid()) {
        if (m_playlist) {
            if (rowCount()) {
                beginRemoveRows(QModelIndex(), 0, rowCount() - 1);
                m_playlist->clear();
                endRemoveRows();
            }
            delete m_playlist;
        }
        m_playlist = new Mlt::Playlist(playlist);
        if (!m_playlist->is_valid()) {
            delete m_playlist;
            m_playlist = 0;
            return;
        }
        if (m_playlist->count() > 0) {
            beginInsertRows(QModelIndex(), 0, m_playlist->count() - 1);
            endInsertRows();
        }
        // do not let opening a clip change the profile!
        MLT.profile().set_explicit(true);
        if (Settings.playerGPU() && Settings.playlistThumbnails() != "hidden")
            refreshThumbnails();
        emit loaded();
    }
}

I tried creating vector that hold the actual filenames and then every time I switch to playlist I would clear the m_model.playlist and add the new files but that process is slow, specially when you have multiple files, so that was not not a option.

I can't think of any other way now, I looking into using a vector of models.

[SGaist]

Why are you trying to pass reference around rather than pointers ?

[hbatalha]

@SGaist I am not, that is how Mlt::Playlist works.

[SGaist]

You do that in your PlaylistModel. You are passing everything by reference although you store all your PlayLists as pointers. Hence fail to see why you are using references in you model interface. Also why are you creating so many copies of your PlayList objects ?

[hbatalha]

@SGaist said in Creating QTableView dynamically / Creating new playlists:

You are passing everything by reference although you store all your PlayLists as pointers.

That's how I found the code. However I changed that, but it crashes every time I switch back to a playlist:

void PlaylistModel::setPlaylist(Mlt::Playlist *playlist)
{
    if (playlist->is_valid())
    {
        if (m_playlist)
        {
            if (rowCount())
            {
                beginRemoveRows(QModelIndex(), 0, rowCount() - 1);
//                m_playlist->clear();
                endRemoveRows();
            }
            // delete m_playlist;
        }
        m_playlist = playlist; // crashes here
        if (!m_playlist->is_valid())
        {
            // delete m_playlist;
            m_playlist = 0;
            return;
        }
        if (m_playlist->count() > 0)
        {
            beginInsertRows(QModelIndex(), 0, m_playlist->count() - 1);
            endInsertRows();
        }
        // do not let opening a clip change the profile!
        MLT.profile().set_explicit(true);
        if (Settings.playerGPU() && Settings.playlistThumbnails() != "hidden")
            refreshThumbnails();
        emit loaded();
    }
}
``

[SGaist]

One thing you should do: call begin/endResetModel when you replace the playlist.

Then, the debugger is your friend.

[hbatalha]

@SGaist That did it, can't thank you enough.

Thank you all for the time and help.