How to change selected row height in QListView

Binary Soft

Hello,
I created a custom QStyledItemDelegate for QListView. When I click (select) a row of listview, I want to set row height to (eg. double etc. ).

When I debug it. sizeHint of opt.state & QStyle::State_Selected is never reached. How Can I solve it?
Thanks

class ListViewDelegate : public QStyledItemDelegate
{
public:
    void paint(QPainter* painter, const QStyleOptionViewItem& option, const QModelIndex& index) const {
		QStyleOptionViewItemV4 opt = option;
		initStyleOption(&opt, index);

		QString str1 = index.model()->data(index.model()->index(index.row(), 1)).toString();

		if (opt.state & QStyle::State_Selected) {
		   painter->setPen(opt.palette.color(cg, QPalette::HighlightedText));
		}
	 
		painter->setPen(Qt::black);
		painter->drawText(opt.rect,opt.displayAlignment, str1);
    
	}

	QSize sizeHint(const QStyleOptionViewItem & option, const QModelIndex & index ) const {
		QSize result = QStyledItemDelegate::sizeHint(option, index);
		
QStyleOptionViewItemV4 opt = option;
		initStyleOption(&opt, index);

		if (opt.state & QStyle::State_Selected) 
			result.setHeight(result.height()*3);
		else
			result.setHeight(result.height()*1);
			
		return result;
	}
};

JonB

@Binary-Soft
Excuse me if this is wrong/obvious, I don't do C++ regularly. But have you (presumably in your .h file?) ensured you have marked your QSize sizeHint() declaration with the override keyword, else it will be a distinct method with the same name but not actually overriding?

dheerendra

Can you confirm whether sizeHint method is called ? This will be first step. Your function signature looks right.

Binary Soft

@JonB said in How to change selected row height in QListView:

keyword
Now I change some code. row height is changed when selected. But selected row is overlapped to next row. I think layout is not adjust for selected row.

Thanks.

.h

#ifndef ListViewDelegate _H
#define listviewdelegate _H

#include <QStyledItemDelegate>
#include <QWidget>
#include <QPainter>

#include <QDebug>
#include <QMouseEvent>
 

class ListViewDelegate  : public QStyledItemDelegate
{

    Q_OBJECT
public:
    ListViewDelegate (QWidget *parent = 0): QStyledItemDelegate(parent){
       intSelID=-1;
    }

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

    bool editorEvent(QEvent *event, QAbstractItemModel *model, const QStyleOptionViewItem &option, const QModelIndex &index);

private:
    int intSelID;



};

#endif // ListViewDelegate _H

#include "listviewdelegate.h"

void ListViewDelegate::paint(QPainter *painter, const QStyleOptionViewItem &option, const QModelIndex &index) const
{
    if(!index.isValid()) return;

    QStyleOptionViewItemV4 opt = option;

    QString str1 = index.model()->data(index.model()->index(index.row(), 1)).toString();

    QStyle *style = opt.widget ? opt.widget->style() : QApplication::style();
    style->drawControl(QStyle::CE_ItemViewItem, &opt, painter, opt.widget);

    QPalette::ColorGroup cg = opt.state & QStyle::State_Enabled ? QPalette::Normal : QPalette::Disabled;
    if (cg == QPalette::Normal && !(opt.state & QStyle::State_Active))
        cg = QPalette::Inactive;

    painter->setPen(Qt::black);

    painter->drawText(opt.rect, opt.displayAlignment,  str1);
    painter->setPen(Qt::yellow);

}

QSize ListViewDelegate::sizeHint(const QStyleOptionViewItem &option, const QModelIndex &index) const
{
    if(!index.isValid())  return QSize();
    QSize result = QStyledItemDelegate::sizeHint(option, index);

    if (intSelID == index.row()) {
        result.setHeight(result.height()*2);
        qDebug() << " select row";
    }
    else {
        result.setHeight(result.height()*1);
        qDebug() << " de select";
    }
    return result;
}

bool ListViewDelegate::editorEvent(QEvent *event, QAbstractItemModel *model, const QStyleOptionViewItem &option, const QModelIndex &index)
{
    QMouseEvent *mouseEvent = static_cast<QMouseEvent*>(event);
    if (event->type() == QEvent::MouseButtonPress)
    {
        if(intSelID==index.row())
            intSelID= -1;
        else
            intSelID = index.row();

        ListViewDelegate::sizeHint(option,index);
    }
    return QStyledItemDelegate::editorEvent(event, model, option, index);
}

Binary Soft

@dheerendra
Thanks.
I use debug, sizeHind is work. Now row height is change but layout's height is not change.

dheerendra

which layout is not changing ?

Binary Soft

@dheerendra !

Please see two pictures (before select and after select)
I change selected row Item's height *1.8. Item's height is changed but it overlapped on next item.

[alt text]( image url)

Binary Soft

@Binary-Soft
I already set listview's setUniformItemSizes to false.
ui->listView->setUniformItemSizes(false);

qwasder85

@Binary-Soft

YourListView->setStyleSheet(QString("::item:selected { height: %1; }").arg(new_height));

...
I know, the topic is old. But just to keep future devs from spending too much time on something like this.