QListView word wrap

[marcel]

It is the parent list view.
When you set the delegate with QAbstractItemView::setItemDelegate, the view takes ownership of the delegate and reparents it.

What you see in that code is actually QObject:arent().

Regards

[jiveaxe]

Is this equivalent?

QSize PartOfSpeechItemDelegate::sizeHint(QWidget *parent, const QStyleOptionViewItem& option, const QModelIndex& index) const
{
    QAbstractItemView *view = dynamic_cast<QAbstractItemView*>(parent);
    QFontMetrics fontMetrics = view->fontMetrics();
    QRect rect = fontMetrics.boundingRect(index.data().toString());
    int proportion = (rect.width() / (view->width() + 4));
    if (proportion == 0 || rect.width() > view->width())
        proportion++;
 
    return QSize(view->width() - 4, rect.height() * proportion);
}

QSize PartOfSpeechItemDelegate::sizeHint(QWidget *parent, const QStyleOptionViewItem& option, const QModelIndex& index) const
{
    QAbstractItemView *view = dynamic_cast<QAbstractItemView*>(parent);
    QFontMetrics fontMetrics = view->fontMetrics();
    QRect rect = fontMetrics.boundingRect(index.data().toString());
    int proportion = (rect.width() / (view->width() + 4));
    if (proportion == 0 || rect.width() > view->width())
        proportion++;

    return QSize(view->width() - 4, rect.height() * proportion);
}

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[marcel]

Is PartOfSpeechItem delegate a QAbstractItemDelegate?
Because the signature of QAbstractItemDelegate::sizeHint differs from your implementation. It does not have a QWidget* parameter.


Regards

[jiveaxe]

I was trying using this sizeHint() code to solve my problem. Using this code like it is give me an error (‘parent’ was not declared in this scope) while changing the signature like in my previous post, program compile without error, even if it doesn't solve the problem.

Bye

[marcel]

Well, I don't know if it is a typo, but in your code should be parent() not parent.
You must call the function. There is not parent object.

Regards

[jiveaxe]

Sorry marcel if i ask you in this manner, but can you review the sizeHint() in this post and explain me a way for changing row height if text wraps ? (with that code the rows height are always one line independently if text wraps, and the wrapped text overlaps the rows below).

Regards

[serega]

I haven't played with my application for a while, now I came back to it and to sizeHint(). Below is my current implementation, which provides may be not perfect, but very good results.
There was some questions above regarding parent(). Ideally QAbstractItemDelegate do not need to know about QAbstractItemView, but in my case I have to set the view as a parent of the delegate because I need the width of the view to determine the height.

QSize PartOfSpeechItemDelegate::sizeHint(const QStyleOptionViewItem &option, const QModelIndex &index) const
{
    QAbstractItemView *view = dynamic_cast<QAbstractItemView*>(parent());
    QFontMetricsF fontMetrics(view->fontMetrics());
    QString str = index.data().toString().trimmed();
    QStringList words = str.split(QChar(' '));
    QRectF boundingRect = fontMetrics.boundingRect(str);
    int width = view->viewport()->width() - 6;
    int times = 0;
    while (words.size() > 0) {
        times++;
        qreal lineWidth = 0;
        bool enoughSpace = true;
        do {
            QString word = words.first();
            qreal wordWidth = fontMetrics.width(word);
            if (wordWidth + lineWidth < width) {
                lineWidth += wordWidth;
                lineWidth += fontMetrics.width(QChar(' '));
                words.removeFirst();
            } else 
                enoughSpace = false;
 
        } while (enoughSpace && words.size() > 0);
    }
    return QSize(width, boundingRect.height() * times - times + 1);
}
 
void PartOfSpeechItemDelegate::paint(QPainter *painter,
                                     const QStyleOptionViewItem &option, const QModelIndex &index) const
{
    QRect rect(option.rect.topLeft(), option.rect.bottomRight());
    if (option.state & QStyle::State_Selected)
        painter->fillRect(rect, option.palette.highlight());
 
    painter->save();
    painter->setPen(QPen(Qt::gray));
    painter->drawLine(rect.topLeft(), rect.topRight());
    painter->restore();
 
    rect.setLeft(rect.left() + 4);
    rect.setTop(rect.top() + 2);
    rect.setRight(rect.right() - 2);
    painter->drawText(rect, Qt::TextWordWrap , index.data().toString());
}

QSize PartOfSpeechItemDelegate::sizeHint(const QStyleOptionViewItem &option, const QModelIndex &index) const
{
    QAbstractItemView *view = dynamic_cast<QAbstractItemView*>(parent());
    QFontMetricsF fontMetrics(view->fontMetrics());
    QString str = index.data().toString().trimmed();
    QStringList words = str.split(QChar(' '));
    QRectF boundingRect = fontMetrics.boundingRect(str);
    int width = view->viewport()->width() - 6;
    int times = 0;
    while (words.size() > 0) {
        times++;
        qreal lineWidth = 0;
        bool enoughSpace = true;
        do {
            QString word = words.first();
            qreal wordWidth = fontMetrics.width(word);
            if (wordWidth + lineWidth < width) {
                lineWidth += wordWidth;
                lineWidth += fontMetrics.width(QChar(' '));
                words.removeFirst();
            } else 
                enoughSpace = false;
                
        } while (enoughSpace && words.size() > 0);
    }
    return QSize(width, boundingRect.height() * times - times + 1);
}

void PartOfSpeechItemDelegate::paint(QPainter *painter,
                                     const QStyleOptionViewItem &option, const QModelIndex &index) const
{
    QRect rect(option.rect.topLeft(), option.rect.bottomRight());
    if (option.state & QStyle::State_Selected)
        painter->fillRect(rect, option.palette.highlight());
    
    painter->save();
    painter->setPen(QPen(Qt::gray));
    painter->drawLine(rect.topLeft(), rect.topRight());
    painter->restore();
    
    rect.setLeft(rect.left() + 4);
    rect.setTop(rect.top() + 2);
    rect.setRight(rect.right() - 2);
    painter->drawText(rect, Qt::TextWordWrap , index.data().toString());
}

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My view:

void PartOfSpeechItemView::resizeEvent(QResizeEvent *resizeEvent)
{
    reset();
    QListView::resizeEvent(resizeEvent);
}

void PartOfSpeechItemView::resizeEvent(QResizeEvent *resizeEvent)
{
    reset();
    QListView::resizeEvent(resizeEvent);
}

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See the attachment how it looks like.

serega.