Built-in type casting to QVariant error.

Charlie_Hdz

Hi guys.

I'm creating a model to show some AudioMetaData,so I created a class AudioMetaData:

@#ifndef AUDIOMETADATA_H
#define AUDIOMETADATA_H
#include <QObject>
#include <QString>
#include <QDate>
#include <QTime>

class AudioMetaData
{
public:
explicit AudioMetaData(QString* n,QDate* d,QString* a,QString* al,
QString* g,QTime* du,int* r):m_name(n),m_dateOfRelease(d),
m_artist(a),m_album(al),m_genre(g),m_duration(du),m_Rating(r){}

//!
AudioMetaData();
~AudioMetaData();
AudioMetaData(const AudioMetaData& other);

//Access Function.
QString name()const{return *m_name;}
void setName(QString* name){m_name=name;}
QDate dateOfRelease()const{return *m_dateOfRelease;}
void setDate(QDate* date){m_dateOfRelease=date;}
QString artist()const{return *m_artist;}
void setArtist(QString* artist){m_artist=artist;}
QString album()const{return *m_album;}
void setAlbum(QString* album){m_album=album;}
QString genre()const{return *m_genre;}
void setGenre(QString* genre){m_genre=genre;}
QTime duration()const{return *m_duration;}
void setDuration(QTime* duration){m_duration=duration;}

private:
QString* m_name;
QDate* m_dateOfRelease;
QString* m_artist;
QString* m_album;
QString* m_genre;
QTime* m_duration;
int* m_Rating;
};

Q_DECLARE_METATYPE(AudioMetaData)
#endif // AUDIOMETADATA_H@

And the model too...

@#ifndef PLAYLISTMODEL_H
#define PLAYLISTMODEL_H

#include <QAbstractTableModel>
#include <QModelIndex>
#include <QList>
#include <QVariant>
#include <QMetaEnum>
#include "audiometadata.h"

class PlayListModel : public QAbstractTableModel
{
Q_OBJECT
public:
PlayListModel(QList<AudioMetaData*> lst, QObject* parent=0):
QAbstractTableModel(parent),m_lstAudioMetaObj(lst){}
PlayListModel();
~PlayListModel();
//Implemented Function
QVariant headerData(int section, Qt::Orientation orientation, int role = Qt::DisplayRole) const;
int rowCount(const QModelIndex &parent= QModelIndex()) const;
int columnCount(const QModelIndex &parent=QModelIndex()) const;
QVariant data(const QModelIndex &index, int role=Qt::DisplayRole) const;
private:
QList<AudioMetaData*>m_lstAudioMetaObj;
};

#endif // PLAYLISTMODEL_H
@

and its implementations:

@#include "playlistmodel.h"

PlayListModel::PlayListModel()
{

setHeaderData(0,Qt::Horizontal,QString("Name"),Qt::DisplayRole);

}

PlayListModel::~PlayListModel()
{

}

QVariant PlayListModel::headerData(int section, Qt::Orientation orientation, int role) const{

}

int PlayListModel::rowCount(const QModelIndex &parent) const{
return m_lstAudioMetaObj.size();
}

int PlayListModel::columnCount(const QModelIndex &parent) const{
return 7;
}

QVariant PlayListModel::data(const QModelIndex &index, int role) const{
if(!index.isValid())
return QVariant();
if(index.row()>=m_lstAudioMetaObj.size())
return QVariant();
if(role==Qt::DisplayRole){
qRegisterMetaType<AudioMetaData>("AudioMetaData");//Desesperate Try
return QVariant::fromValue(m_lstAudioMetaObj[index.row()]);//Here is the beast
}
else
return QVariant();

}
@

Well, the problem is in the line 34 of the PlayListModel.cpp, Im trying to return a QVariant modeling a AudioMetaData from a QList...but the compiler set me this error:

error: invalid application of 'sizeof' to incomplete type 'QStaticAssertFailure<false>'
enum {Q_STATIC_ASSERT_PRIVATE_JOIN(q_static_assert_result, COUNTER) = sizeof(QStaticAssertFailure<!!(Condition)>)}

I'll be very appreciate if someone can help me.

Thank You.

ckakman

Hi,

Your list does not contain AudioMetaData objects but pointers to AudioMetaData objects, but you register AudioMetaData with qRegisterMetaType, not a pointer.

By the way why is all your private data in AudioMetaData pointers? You don't any pointers there. Just use values. QString is "implicitly shared":http://doc.qt.io/qt-5/shared.html so you can treat it like an int and QTime is sizeof(int). It looks like m_Rating is not an array. If it is I'd suggest that you replace it with a vector, otherwise just use an int.

Charlie_Hdz

Hi ckakman, I changed the pointersto values and the register of AudioMetaData too, as you said, and everthing is working now.

Thanks a lot