Background of a selected QItemDelegate

[schall_l]

Hi,

Is there a simple way to use a gradient for the box displayed as a background of a selected Item in a class that derives from QItemDelegate ?
I was first thinking to reimplement paint by doing something like:

void 
MyDelegate::paint( QPainter* painter, const QStyleOptionViewItem& option, const QModelIndex& i ) const
 
{
 
  // Special treatment for the selected state
  if (option.state & QStyle::State_Selected) {
 
    QItemDelegate::paint( painter, option, i );
    QRect selectedRect = option.rect; 
    selectedRect.setLeft(0);
    QLinearGradient linearGradient(0, selectedRect.top() , 0, selectedRect.top() + 100);
    linearGradient.setColorAt(0.0, QColor(93,148,214));
    linearGradient.setColorAt(0.2, QColor(25,86,173));
    painter->setBrush(linearGradient); 		
    painter->fillRect(selectedRect, linearGradient);		
 
    // But this is not convenient because it makes me need to reimplement also
    // the display of the check box, decoration, text,...
    .....
    .....
 
  } else {
 
    QItemDelegate::drawBackground( painter, option, i );
 
  }
}

void 
MyDelegate::paint( QPainter* painter, const QStyleOptionViewItem& option, const QModelIndex& i ) const

{

  // Special treatment for the selected state
  if (option.state & QStyle::State_Selected) {

    QItemDelegate::paint( painter, option, i );
    QRect selectedRect = option.rect; 
    selectedRect.setLeft(0);
    QLinearGradient linearGradient(0, selectedRect.top() , 0, selectedRect.top() + 100);
    linearGradient.setColorAt(0.0, QColor(93,148,214));
    linearGradient.setColorAt(0.2, QColor(25,86,173));
    painter->setBrush(linearGradient); 		
    painter->fillRect(selectedRect, linearGradient);		
  
    // But this is not convenient because it makes me need to reimplement also
    // the display of the check box, decoration, text,...
    .....
    .....

  } else {
  
    QItemDelegate::drawBackground( painter, option, i );

  }
}

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[schall_l]

I just saw that QT4.4 comes with a new class called QStyledItemDelegate.
I am wondering if using QStyledItemDelegate together with a style sheet would be simpler then reimplementing paint ?
Does anyone has any project sample to look at ?

[jpn]

I just saw that QT4.4 comes with a new class called QStyledItemDelegate.
I am wondering if using QStyledItemDelegate together with a style sheet would be simpler then reimplementing paint ?
Does anyone has any project sample to look at ?

Yes, it is a lot easier. There are examples in docs:

• Customizing QListView
• Customizing QTableView
• Customizing QTreeView

[schall_l]

Is it possible to define style sheet for a custom class that derives directly from QStyledItemDelegate ?

Something like this don't seems to work.

class SideBarDelegate : public QStyledItemDelegate
{
	Q_OBJECT
 
public:
	void paint( QPainter *painter , const QStyleOptionViewItem &option, const QModelIndex &index ) const;
	QSize sizeHint( const QStyleOptionViewItem &option, const QModelIndex &index ) const;
};

class SideBarDelegate : public QStyledItemDelegate
{
	Q_OBJECT

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

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SideBarDelegate::item:selected:active{
    background: qlineargradient(x1: 0, y1: 0, x2: 0, y2: 1, stop: 0 #6ea1f1, stop: 1 #567dbc);
}
 
SideBarDelegate::item:selected:!active {
    background: qlineargradient(x1: 0, y1: 0, x2: 0, y2: 1, stop: 0 #6b9be8, stop: 1 #577fbf);
}

SideBarDelegate::item:selected:active{
    background: qlineargradient(x1: 0, y1: 0, x2: 0, y2: 1, stop: 0 #6ea1f1, stop: 1 #567dbc);
}

SideBarDelegate::item:selected:!active {
    background: qlineargradient(x1: 0, y1: 0, x2: 0, y2: 1, stop: 0 #6b9be8, stop: 1 #577fbf);
}

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[jpn]

You must call the base class implementation; QStyledItemDelegate::paint(). What do you need a reimplementation for?