Qt学习笔记，再次分析EVA源码之后得出的结论-QListView，QListViewItem(Qt3);Q3ListView,Q3ListViewItem(Qt4)

Qt学习笔记，再次分析EVA源码之后得出的结论-QListView，QListViewItem(Qt3);Q3ListView,Q3ListViewItem(Qt4)

今天再次分析了Eva的源码，也看了qt3中QListView和QListViewItem手册，在Eva中实现item paint的方式如下：

void EvaListViewItem::paintCell( QPainter * painter, const QColorGroup & colourGroup, int column, int width, int align )
{
    if( ! isVisible() ) return;
    if ( column == 0){
        QBrush *brush;
        QPalette palette;

        EvaListView *lv = dynamic_cast<EvaListView *> (listView());
        if( !lv ) return;

        palette = lv->viewport()->palette();
        brush   = 0;

        const BackgroundMode bgmode = lv->viewport()->backgroundMode();
        const QColorGroup::ColorRole crole = QPalette::backgroundRoleFromMode( bgmode );
        if ( colourGroup.brush( crole ) != lv->colorGroup().brush( crole ) )
            painter->fillRect( 0, 0, width, height(), colourGroup.brush( crole ) );
        else
            lv->paintEmptyArea( painter, QRect( 0, 0, width, height() ) );

        if ( isSelected() ) {
            brush = new QBrush( palette.color(QPalette::Active, QColorGroup::Highlight) );
            // painter->setPen( palette.color(QPalette::Active, QColorGroup::Text) );
        } else {
            // painter->setPen( palette.color(QPalette::Normal, QColorGroup::Text) );
            }

        int icon_width = 0;
        if(m_icon){
            icon_width = lv->itemMargin() + m_icon->width();
        }
        // TODO: Change the font for highlighted text
        m_richText->draw( painter, lv->itemMargin() + icon_width, 0, 
                                QRect( icon_width, 0, width, height() ), colourGroup, brush );
        //setHeight( m_RichText->height() );
        if(m_icon){
            int xo = lv->itemMargin();
            int yo = ( height() - m_icon->height() ) / 2;
            painter->drawPixmap( xo, yo, *m_icon );
        }
        int height = m_richText->height();
        if(m_icon && m_icon->height() > m_richText->height()){
            height = m_icon->height();
        }
        height += 4;
        setHeight( height );
        widthChanged( 0 );
        delete brush;
    } else {
        QListViewItem::paintCell( painter, colourGroup, column, width, align );
    }
}

注：上面的QListViewItem中qt4中应该改为Q3ListViewItem

再分析了Qt4中的QListWidget和QTreeWidget,得出的结论是：在qt4中qt放弃了对如Qt3中对Listview和ListViewItem的支持，在看Qt3的手册的时候可以看到：

void QListView::insertItem ( QListViewItem * i ) [virtual] 
Inserts item i into the list view as a top-level item. You do not need to call this unless you've called takeItem(i) or QListViewItem::takeItem(i) and need to reinsert i elsewhere. 

有insertItem函数。再看看qt4中的某一个Q*Widget，比如就是QListWidget：

void QListWidget::insertItem ( int row, QListWidgetItem * item )
Inserts the item at the position in the list given by row.
See also addItem().

可以看到他们就是一致的，不妨在看看QTreeWidget：

void QTreeWidget::insertTopLevelItem ( int index, QTreeWidgetItem * item )
Inserts the item at index in the top level in the view.
If the item has already been inserted somewhere else it wont be inserted.

也有类似的操作。

我们知道在qt4中要像view中加入数据，就要使用qt4特有的interview框架的model/view机制。但是在qt3中向view中加入数据（item）就有直接的insert函数，在qt4中的Q*Widget也有类似的insert函数，所以：

在qt4中把qt3中类似的view的insertItem函数和class演变成了Qt4中的Q*Widget，当然他们的实现功能几乎没有太大不一样。