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 ) );elselv->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 textm_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。