Problem with QItemDelegate

[chandan]

Hi everyone,
How can I change the size of the font of the item in a list using QItemDelegate's paint method? I have tried to change the painter font in the paint method but it is not reflecting the changes in the list view.
Please help me.
Thanks in advance.

[Lykurg]

Can we see your code? Without it is hard to tell. Use QStyleOptionViewItem and set the font there.

[chandan]

Thanks for your reply.
Here is my code and I want to change the font using painter of the paint method. Is it possible please?
void CCameraUICustomDelegate:aint(QPainter *painter,
const QStyleOptionViewItem &option,
const QModelIndex &index) const{
QVariant variant = index.data();
/*QPainter *qPainter = new QPainter;*/
//QString stringData = variant.toString();
painter->save();
painter->setFont(QFont("Times", 30, QFont::Bold));
painter->restore();

QStyledItemDelegate:aint(painter,option,index);
}

[Lykurg]

With save and restore everything in between is lost! So your code wont work. Try

painter->setFont(QFont("Times", 30, QFont::Bold));
QStyledItemDelegate::paint(painter,option,index);

painter->setFont(QFont("Times", 30, QFont::Bold));
QStyledItemDelegate::paint(painter,option,index);

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If that does not work, alter as told option.

[Lykurg]

Ehm, and did you try QWidget::setFont() on your QListView/QListWidget?

[chandan]

Still it is not working. Is there any other way to do that please?

[chandan]

May be in the future I have to make some more changes in my list. That's why I have to subclass QStyledDelegate. So I have to change the font in the paint method.

[Lykurg]

So did you alter option? And you can alternatively draw all yourself without calling the base function. Then you can change the painter like you want.

[chandan]

I did alter option but didn't work. I will try to implement the whole function myself. Anyway thanks for your help.

[Lykurg]

Well, to be honest, I don't think you have really tried it, because it works fine. It is more likely you use wrong code. But without seeing anything.... The simple setFont solution with a custom delegate works perfect:

#include <QtGui>
 
class delegate : public QStyledItemDelegate
{
  public:
    delegate(QObject* parent = 0) : QStyledItemDelegate(parent)
    {}
 
    void paint(QPainter* painter, const QStyleOptionViewItem& option, const QModelIndex& index) const
    {
      QStyledItemDelegate::paint(painter, option, index);
    }
};
 
int main(int argc, char* argv[])
{
  QApplication a(argc, argv);
 
  QStringList list;
  list << "a" << "b" << "c";
 
  QListWidget w;
  w.setFont(QFont("Courier", 30));
  delegate d;
  w.setItemDelegate(&d);
  w.addItems(list);
  w.show();
 
  QListView lv;
  lv.setFont(QFont("Courier", 30));
  lv.setItemDelegate(&d);
  QStringListModel m;
  m.setStringList(list);
  lv.setModel(&m);
  lv.show();
 
 
  return a.exec();
}

#include <QtGui>

class delegate : public QStyledItemDelegate
{
  public:
    delegate(QObject* parent = 0) : QStyledItemDelegate(parent)
    {}

    void paint(QPainter* painter, const QStyleOptionViewItem& option, const QModelIndex& index) const
    {
      QStyledItemDelegate::paint(painter, option, index);
    }
};

int main(int argc, char* argv[])
{
  QApplication a(argc, argv);

  QStringList list;
  list << "a" << "b" << "c";

  QListWidget w;
  w.setFont(QFont("Courier", 30));
  delegate d;
  w.setItemDelegate(&d);
  w.addItems(list);
  w.show();

  QListView lv;
  lv.setFont(QFont("Courier", 30));
  lv.setItemDelegate(&d);
  QStringListModel m;
  m.setStringList(list);
  lv.setModel(&m);
  lv.show();


  return a.exec();
}

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