segfaulting delegate, please help

[janorcutt]

hi, im having a big problem with my custom delegate, heres the code from the mainwindow class:

mediaItemDelegate *delegate;
ui->listView_2->setModel(model);
ui->listView_2->setItemDelegate(delegate);

mediaItemDelegate *delegate;
ui->listView_2->setModel(model);
ui->listView_2->setItemDelegate(delegate);

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and the delegate itself

class mediaItemDelegate : public QItemDelegate
{
    Q_OBJECT
public:
    mediaItemDelegate(QObject *parent = 0);
 
    void paint(QPainter *painter, const QStyleOptionViewItem &option, const QModelIndex &index) const = 0;
    QSize sizeHint(const QStyleOptionViewItem &option, const QModelIndex &index) const = 0;
 
};

class mediaItemDelegate : public QItemDelegate
{
    Q_OBJECT
public:
    mediaItemDelegate(QObject *parent = 0);

    void paint(QPainter *painter, const QStyleOptionViewItem &option, const QModelIndex &index) const = 0;
    QSize sizeHint(const QStyleOptionViewItem &option, const QModelIndex &index) const = 0;

};

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#include "mediaitemdelegate.h"
 
mediaItemDelegate::mediaItemDelegate(QObject *parent):
        QItemDelegate(parent)
{
}
 
void mediaItemDelegate::paint(QPainter *painter, const QStyleOptionViewItem &option, const QModelIndex &index) const
{
    if(index.isValid()){
        const int left = option.rect.left();
        const int top = option.rect.top();
        const int width = option.rect.width();
        QFont titlefont(option.font);
        titlefont.setBold(true);
        titlefont.setPointSize(titlefont.pointSize());
        int height = (2 * titlefont.pixelSize()) + 10;
        int padding = 3;
        QColor foregroundColor = (option.state.testFlag(QStyle::State_Selected))?
            option.palette.color(QPalette::HighlightedText):option.palette.color(QPalette::Text);
        //base pixmap
        QPixmap pixmap(width, height);
        pixmap.fill(Qt::transparent);
        QPainter p(&pixmap);
        p.translate(-option.rect.topLeft());
 
        //icon time
        QIcon icon;
        int iconwidth = height - 6;
        icon.addFile(QString::fromUtf8(":/icons/icons/hi48-action-filename-filetype-amarok.png"), QSize(iconwidth,iconwidth),QIcon::Normal, QIcon::On);
        if(!icon.isNull()){
            icon.paint(&p, left + padding, top + padding, iconwidth, iconwidth, Qt::AlignCenter, QIcon::Normal);
        }
 
        //now for text
        QString artist, album, title,duration;
        QMap<int, QVariant> map(index.model()->itemData(index));
        title.append(map.value(mediaItem::TitleRole).toString());
        artist.append(map.value(mediaItem::ArtistRole).toString());
        album.append(map.value(mediaItem::AlbumRole).toString());
        duration.append(map.value(mediaItem::DurationRole).toString());
 
        QFont font(option.font);
        font.setBold(true);
        int lefttext = iconwidth + 2 * padding;
        int topoff = (height - iconwidth) / 2;
        QTextOption txtopt(Qt::AlignLeft | Qt::AlignBottom);
        txtopt.setWrapMode(QTextOption::WordWrap);
        QRect titlerect(left + lefttext, top + padding, (width / 2) - padding - lefttext, topoff);
        QRect artistrect(left + lefttext, top + (2*padding) + topoff + 1, (width / 2) - padding - lefttext, topoff);
        QRect albumrect(left + lefttext + titlerect.width() + padding, top + (2*padding) + topoff + 1, (width / 2) - padding - lefttext, topoff);
        QRect durrect(left + lefttext + titlerect.width() + padding, top + padding, (width / 2) - padding - lefttext, topoff);
        font.setPixelSize(titlerect.height()/7);
        p.setFont(font);
        p.setPen(foregroundColor);
        p.drawText(QRectF(titlerect), title, txtopt);
        p.drawText(QRectF(artistrect), artist, txtopt);
        txtopt.setAlignment(Qt::AlignRight | Qt::AlignBottom);
        p.drawText(QRectF(albumrect), album, txtopt);
        p.drawText(QRectF(durrect), duration, txtopt);
        p.end();
 
        //hey presto
        painter->drawPixmap(option.rect.topLeft(), pixmap);
        /*
        QPixmap reflect = Utilities::reflection(pixmap);
        painter->drawPixmap(option.rect.topleft() + QPoint(0, size.width() + 1), reflect);
        */
    }
}
 
QSize mediaItemDelegate::sizeHint(const QStyleOptionViewItem &option, const QModelIndex &index) const
{
    if(!index.isValid()){
        return QSize(0, 0);
    }
 
    int width = 0;
    QFont titlefont(option.font);
    titlefont.setBold(true);
    titlefont.setPointSize(titlefont.pointSize());
    int height = (2 * titlefont.pixelSize()) + 10;
    return QSize(width, height);
}

#include "mediaitemdelegate.h"

mediaItemDelegate::mediaItemDelegate(QObject *parent):
        QItemDelegate(parent)
{
}

void mediaItemDelegate::paint(QPainter *painter, const QStyleOptionViewItem &option, const QModelIndex &index) const
{
    if(index.isValid()){
        const int left = option.rect.left();
        const int top = option.rect.top();
        const int width = option.rect.width();
        QFont titlefont(option.font);
        titlefont.setBold(true);
        titlefont.setPointSize(titlefont.pointSize());
        int height = (2 * titlefont.pixelSize()) + 10;
        int padding = 3;
        QColor foregroundColor = (option.state.testFlag(QStyle::State_Selected))?
            option.palette.color(QPalette::HighlightedText):option.palette.color(QPalette::Text);
        //base pixmap
        QPixmap pixmap(width, height);
        pixmap.fill(Qt::transparent);
        QPainter p(&pixmap);
        p.translate(-option.rect.topLeft());

        //icon time
        QIcon icon;
        int iconwidth = height - 6;
        icon.addFile(QString::fromUtf8(":/icons/icons/hi48-action-filename-filetype-amarok.png"), QSize(iconwidth,iconwidth),QIcon::Normal, QIcon::On);
        if(!icon.isNull()){
            icon.paint(&p, left + padding, top + padding, iconwidth, iconwidth, Qt::AlignCenter, QIcon::Normal);
        }

        //now for text
        QString artist, album, title,duration;
        QMap<int, QVariant> map(index.model()->itemData(index));
        title.append(map.value(mediaItem::TitleRole).toString());
        artist.append(map.value(mediaItem::ArtistRole).toString());
        album.append(map.value(mediaItem::AlbumRole).toString());
        duration.append(map.value(mediaItem::DurationRole).toString());

        QFont font(option.font);
        font.setBold(true);
        int lefttext = iconwidth + 2 * padding;
        int topoff = (height - iconwidth) / 2;
        QTextOption txtopt(Qt::AlignLeft | Qt::AlignBottom);
        txtopt.setWrapMode(QTextOption::WordWrap);
        QRect titlerect(left + lefttext, top + padding, (width / 2) - padding - lefttext, topoff);
        QRect artistrect(left + lefttext, top + (2*padding) + topoff + 1, (width / 2) - padding - lefttext, topoff);
        QRect albumrect(left + lefttext + titlerect.width() + padding, top + (2*padding) + topoff + 1, (width / 2) - padding - lefttext, topoff);
        QRect durrect(left + lefttext + titlerect.width() + padding, top + padding, (width / 2) - padding - lefttext, topoff);
        font.setPixelSize(titlerect.height()/7);
        p.setFont(font);
        p.setPen(foregroundColor);
        p.drawText(QRectF(titlerect), title, txtopt);
        p.drawText(QRectF(artistrect), artist, txtopt);
        txtopt.setAlignment(Qt::AlignRight | Qt::AlignBottom);
        p.drawText(QRectF(albumrect), album, txtopt);
        p.drawText(QRectF(durrect), duration, txtopt);
        p.end();

        //hey presto
        painter->drawPixmap(option.rect.topLeft(), pixmap);
        /*
        QPixmap reflect = Utilities::reflection(pixmap);
        painter->drawPixmap(option.rect.topleft() + QPoint(0, size.width() + 1), reflect);
        */
    }
}

QSize mediaItemDelegate::sizeHint(const QStyleOptionViewItem &option, const QModelIndex &index) const
{
    if(!index.isValid()){
        return QSize(0, 0);
    }

    int width = 0;
    QFont titlefont(option.font);
    titlefont.setBold(true);
    titlefont.setPointSize(titlefont.pointSize());
    int height = (2 * titlefont.pixelSize()) + 10;
    return QSize(width, height);
}

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if anybody can shed some light on why this is segfaulting when i try to the the delegate with QListView::setItemDelegate I would be grateful as im nearly out of bourbon lol

ta janorcutt

[Ginsengelf]

Hi, in your mainwindow code, you just create a pointer to a delegate, but no object.
Use

mediaItemDelegate *delegate = new mediaItemDelegate (/*insert parent here*/);

mediaItemDelegate *delegate = new mediaItemDelegate (/*insert parent here*/);

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Ginsengelf

[janorcutt]

thanks i did that, and now it doesn't compile. I get

/home/james/myTunes/mytunes.cpp:10: error: cannot allocate an object of abstract type ‘mediaItemDelegate’
/home/james/myTunes/mediaitemdelegate.h:25: note:   because the following virtual functions are pure within ‘mediaItemDelegate’:
/home/james/myTunes/mediaitemdelegate.h:30: note: 	virtual void mediaItemDelegate::paint(QPainter*, const QStyleOptionViewItem&, const QModelIndex&) const
/home/james/myTunes/mediaitemdelegate.h:31: note: 	virtual QSize mediaItemDelegate::sizeHint(const QStyleOptionViewItem&, const QModelIndex&) const

/home/james/myTunes/mytunes.cpp:10: error: cannot allocate an object of abstract type ‘mediaItemDelegate’
/home/james/myTunes/mediaitemdelegate.h:25: note:   because the following virtual functions are pure within ‘mediaItemDelegate’:
/home/james/myTunes/mediaitemdelegate.h:30: note: 	virtual void mediaItemDelegate::paint(QPainter*, const QStyleOptionViewItem&, const QModelIndex&) const
/home/james/myTunes/mediaitemdelegate.h:31: note: 	virtual QSize mediaItemDelegate::sizeHint(const QStyleOptionViewItem&, const QModelIndex&) const

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i've declared the delegate class in the header, and included the delegate's source, and i've created the object.
is it something immensely simple that i'm missing here??

[Lykurg]

is it something immensely simple that i'm missing here??

If you ask so: Yes You don't have to declare virtual functions you have to reimp them! So just delete the two " = 0;" from your header file and all should work fine.

[janorcutt]

thanks i just figured that out for myself, that'll teach me to cut and paste

thanks for the help anyway

janorcutt