Creating QTableView dynamically / Creating new playlists

hbatalha

So I have an already created (not my code) QTableView which is used for a media playlist, it is already up and running. The problem is that the app originally was designed to have only playlist, this requirement have changed and now they want to make it possible for the user to create as many playlists as they want to.

I have been tasked to make this possible, the requirement is that this is done with a dropdown at the top to choose a playlist. I have googled for this but few results came up and none was what I need.
I want to know if I can do this working with the already existing QTableView/Playlist without having to re-write the whole thing.

Is this possible? If it is, how can I do it?

I am also thinking about grouping the tableview rows, sort of like QTreeView, can't find a way to do it.

Worth noting that I am a beginner and this is my first time coming in contact with the model/view approach of doing things, I was comfortably using only QTableWidget

SGaist

Hi,

How are these playlist created ?
Where are they stored ?

The most simple here is to list these playlist in your combo box and once a user selects its, reload your QTableWidget content based on it.

mrjj

Hi
using a QTableView + std. item model is not that different from using
the QTableWidget. The QTableWidget just has its model internally and with the view,
you have it externally.

so as @SGaist says, how is the single playlist handled now ?
You need to be able to have a list of playlists or something of that sorts.

JonB

@hbatalha
Since it sounds like you already have a QTableView, I assume it's using your own model (what is its model type?). I don't see any point or need to change to a QTableWidget and copy data. When the user selects in the combo box, just change your model to the new playlist and do a begin/endResetModel(), or simlar.

hbatalha

@SGaist @mrjj

How are these playlist created ?
Where are they stored ?

I am not sure how to answer these questions. As I said I am trying to figure out the code since this is my first contact with model/view programming.

@SGaist @JonB

reload your QTableWidget content based on it.

No, I stated QTableWidget just to tell my background regarding Qt. I will have to keep using QTableView.

hbatalha

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

You need to be able to have a list of playlists or something of that sorts.

I am experimenting having a list of QTableView*

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

When the user selects in the combo box, just change your model to the new playlist and do a begin/endResetModel()

Any example?

SGaist

There's not need to have several QTableView. As was already suggested, you should update the model.

One question that you did not answer: how are you currently handling your playlist ?

You might also be interested in the Qt Media Player example.

hbatalha

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

As was already suggested, you should update the model.

So I should have a list of models?

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

how are you currently handling your playlist ?

I am still not sure how to respond? Should I post the code from PlaylistModel.h?

SGaist

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

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

As was already suggested, you should update the model.

So I should have a list of models?

Why ? You can replace the content of a model.

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

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

how are you currently handling your playlist ?

I am still not sure how to respond? Should I post the code from PlaylistModel.h?

That can be a good start.

hbatalha

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

That can be a good start.

#ifndef PLAYLISTMODEL_H
#define PLAYLISTMODEL_H

#include <QAbstractTableModel>
#include <qmimedata.h>
#include <QStringList>
#include "mltcontroller.h"
#include "MltPlaylist.h"

#define kDetailedMode "detailed"
#define kIconsMode "icons"
#define kTiledMode "tiled"

class PlaylistModel : public QAbstractTableModel
{
    Q_OBJECT
public:
    enum ViewMode {
        Invalid,
        Detailed,
        Tiled,
        Icons,
    };

    enum Columns {
        COLUMN_INDEX = 0,
        COLUMN_THUMBNAIL,
        COLUMN_RESOURCE,
        COLUMN_IN,
        COLUMN_DURATION,
        COLUMN_START,
        COLUMN_DATE,
        COLUMN_COUNT
    };

    enum Fields {
        FIELD_INDEX = Qt::UserRole,
        FIELD_THUMBNAIL,
        FIELD_RESOURCE,
        FIELD_IN,
        FIELD_DURATION,
        FIELD_START,
        FIELD_DATE,
    };

    static const int THUMBNAIL_WIDTH = 80;
    static const int THUMBNAIL_HEIGHT = 45;

    explicit PlaylistModel(QObject *parent = 0);
    ~PlaylistModel();
    int rowCount(const QModelIndex& parent = QModelIndex()) const;
    int columnCount(const QModelIndex& parent = QModelIndex()) const;
    QVariant data(const QModelIndex &index, int role = Qt::DisplayRole) const;
    QVariant headerData(int section, Qt::Orientation orientation, int role) const;
    Qt::DropActions supportedDropActions() const;
    bool insertRows(int row, int count, const QModelIndex & parent = QModelIndex());
    bool removeRows(int row, int count, const QModelIndex & parent = QModelIndex());
    bool moveRows(const QModelIndex &sourceParent, int sourceRow, int count, const QModelIndex &destinationParent, int destinationChild);
    void sort(int column, Qt::SortOrder order = Qt::AscendingOrder);
    Qt::ItemFlags flags(const QModelIndex &index) const;
    QStringList mimeTypes() const;
    QMimeData *mimeData(const QModelIndexList &indexes) const;
    bool dropMimeData(const QMimeData *data, Qt::DropAction action, int row, int column, const QModelIndex &parent);
    QModelIndex incrementIndex(const QModelIndex& index) const;
    QModelIndex decrementIndex(const QModelIndex& index) const;
    QModelIndex createIndex(int row, int column) const;
    void createIfNeeded();
    void showThumbnail(int row);
    void refreshThumbnails();
    Mlt::Playlist* playlist() { return m_playlist; }
    void setPlaylist(Mlt::Playlist& playlist);
    void setInOut(int row, int in, int out);

    ViewMode viewMode() const;
    void setViewMode(ViewMode mode);

signals:
    void created();
    void cleared();
    void closed();
    void modified();
    void loaded();
    void dropped(const QMimeData *data, int row);
    void moveClip(int from, int to);
    void inChanged(int in);
    void outChanged(int out);

public slots:
    void clear();
    void load();
    void append(Mlt::Producer&, bool emitModified = true);
    void insert(Mlt::Producer&, int row);
    void remove(int row);
    void update(int row, Mlt::Producer& producer, bool copyFilters = false);
    void updateThumbnails(int row);
    void appendBlank(int frames);
    void insertBlank(int frames, int row);
    void close();
    void move(int from, int to);

private:
    Mlt::Playlist* m_playlist;
    int m_dropRow;
    ViewMode m_mode;
    QList<int> m_rowsRemoved;
};

#endif // PLAYLISTMODEL_H

SGaist

From the looks of it, you would only need to call setPlayList that should trigger a reset of your model and you should be good to go as this will trigger the update of your UI.

hbatalha

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

you would only need to call setPlayList that should trigger a reset of your model and you should be good to go

How will the files added in a playlist be saved when I switched back to a playlist?

SGaist

Since you will have several playlist, you'll likely have them stored using QList or QVector.

There's no deletion happening, you should "exchange" the current playlist with the one selected.

hbatalha

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

Since you will have several playlist

So I will have a QVector<Mlt::Playlist*>?

JonB

@hbatalha
Yes, QVector<Mlt::Playlist*> or QList<Mlt::Playlist*> would be fine.

If you are feeling adventurous, you might even opt for a QMap<QString, Mlt::Playlist*>. If your playlists are simply distinguished by their name in the droplist, saves you having to look it up!

hbatalha

@JonB

It doesn't work, when I switched a playlist it reload with a empty playlist.
The code:

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

    m_playlists.append(playlist);

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

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

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