Using a custom model with QCompleter and QLineEdit

TheFlyingMooseMan

Within my app I have been using a QSqlQueryModel. I want to replace this with my own model (inherited from QAbstractTableModel), as I want to add additional items to the model that drives QCompleter. I could do this in SQL, it'll be much slower. I also want to be able to remove/replace/add items to this model.
I started with the following definition of my own model class. However, the completer does not show a dropdown box when text is entered in my QLineEdit:

class SearchItemModel : public QAbstractTableModel
{
    Q_OBJECT

public:
    SearchItemModel();

    int rowCount(const QModelIndex &parent) const;
    Qt::ItemFlags flags(const QModelIndex &index) const { Q_UNUSED(index); return Qt::ItemIsEnabled | Qt::ItemIsSelectable | Qt::ItemNeverHasChildren; }
    int columnCount(const QModelIndex &parent) const;
    QVariant data(const QModelIndex &index, int role) const;


public slots:
    void populate();

private:
    typedef struct Tuple
    {
        SBIDBase::sb_type itemType;
        int               songID;
        QString           songTitle;
        int 	          performerID;
        QString           performerName;
        int               albumID;
        QString           albumTitle;
        QString           display;
    } Tuple;

    QList<Tuple> _searchItems;

    void _init();
};

The completer is constructed as follows:

    QCompleter* c=new QCompleter();
    c->setModel(qtm);
    c->setCaseSensitivity(Qt::CaseInsensitive);
    c->setModelSorting(QCompleter::CaseSensitivelySortedModel);
    c->setFilterMode(Qt::MatchStartsWith);
    c->setCompletionMode(QCompleter::PopupCompletion);
    c->setCompletionColumn(0);

This works perfectly with the QSqlQueryModel, but not as well with my own model class. Do I need any other method implemented in my model?

Any hint or reply is greatly appreciated!

Thanks,
Roy

raven-worx

@TheFlyingMooseMan
you should rather show the implementation of your SearchItemModel class than the definition.

TheFlyingMooseMan

Here it is:

#include "SearchItemModel.h"

#include "Context.h"
#include "DataAccessLayer.h"

SearchItemModel::SearchItemModel()
{
}

int
SearchItemModel::rowCount(const QModelIndex &parent) const
{
    Q_UNUSED(parent);
    return _searchItems.count();
}

int
SearchItemModel::columnCount(const QModelIndex &parent) const
{
    Q_UNUSED(parent);
    return 3;
}

QVariant
SearchItemModel::data(const QModelIndex &index, int role) const
{
    Q_UNUSED(role);
    if(_searchItems.count()==0 || !index.isValid())
    {
        return QVariant();
    }

    if(index.row()<_searchItems.count())
    {
        Tuple t=_searchItems.at(index.row());
        switch(index.column())
        {
        case 0:
            return t.display;
            break;

        case 1:		// 	itemid
            int itemID;
            switch(t.itemType)
            {
                case SBIDBase::sb_type_song:
                    itemID=t.songID;
                    break;

                case SBIDBase::sb_type_performer:
                    itemID=t.performerID;
                    break;

                case SBIDBase::sb_type_album:
                    itemID=t.albumID;
                    break;

                default:
                    itemID=-1;
            }
            return itemID;
            break;

        case 2:		//	itemtype
            return t.itemType;
            break;
        }
    }
    return QVariant();
}


///	Slots
void
SearchItemModel::populate()
{
    QString query=QString
    (
        "SELECT  "
            "t.type, "
            "t.song_id, "
            "t.title, "
            "t.artist_id, "
            "t.name, "
            "t.record_id, "
            "t.title "
        "FROM "
            "table t "
    )
        .arg(SBIDBase::sb_type_song)
        .arg(SBIDBase::sb_type_album)
        .arg(SBIDBase::sb_type_performer)
    ;

    DataAccessLayer* dal=Context::instance()->getDataAccessLayer();
    QSqlDatabase db=QSqlDatabase::database(dal->getConnectionName());
    dal->customize(query);

    QSqlQuery queryList(query,db);
    while(queryList.next())
    {
        QString key;
        QSqlRecord r=queryList.record();
        struct Tuple t;
        int i=0;
        t.itemType=(SBIDBase::sb_type)queryList.value(i++).toInt();
        t.songID=Common::parseIntFieldDB(&r,queryList.value(i++).toInt());
        t.songTitle=queryList.value(i++).toString();
        t.performerID=Common::parseIntFieldDB(&r,queryList.value(i++).toInt());
        t.performerName=queryList.value(i++).toString();
        t.albumID=Common::parseIntFieldDB(&r,queryList.value(i++).toInt());
        t.albumTitle=queryList.value(i++).toString();

        switch(t.itemType)
        {
        case SBIDBase::sb_type_song:
            t.display=QString("%1 - song by %2").arg(t.songTitle).arg(t.performerName);
            key=SBIDSong::createKey(t.songID);
            break;

        case SBIDBase::sb_type_album:
            t.display=QString("%1 - album by %2").arg(t.albumTitle).arg(t.performerName);
            key=SBIDAlbum::createKey(t.albumID);
            break;

        case SBIDBase::sb_type_performer:
            t.display=QString("%1 - performer").arg(t.performerName);
            key=SBIDPerformer::createKey(t.performerID);
            break;

        default:
            qDebug() << SB_DEBUG_ERROR << "Should not come here";
        }
        _searchItems.append(t);
    }
    QModelIndex s=this->index(0,0);
    QModelIndex e=this->index(3,_searchItems.count());
    emit dataChanged(s,e);
}

As soon as a database connection has been established, an emit populate is issued to retrieve and populate the data structure. Please let me know if anything else is needed.

raven-worx

@TheFlyingMooseMan
you need to call beginResetModel() and endResetModel() at the beginning/end of your populate() method to inform the view about new data.

TheFlyingMooseMan

Thanks for replying!

I added the beginResetModel() and endResetModel() -- no go.
The dropdown box still does not appear -- what does appear is a white bar, probably a fourth the size of the lineEdit widget. If a press a couple of characters and then the cursor down/up keys, I see some choices. But no dropdown box.
On top of that, quitting the app results in a crash.
I appreciate any additional hints or replies!

Thanks,
Roy