Method UpdateVisibleItems

SOUI/src/control/STreeView.cpp:788–899

	}

	void STreeView::UpdateVisibleItems()
	{
        if(!m_adapter) return;
        HTREEITEM hItem = m_tvItemLocator->Position2Item(m_siVer.nPos);
		if (hItem == ITvAdapter::ITEM_NULL)
		{
			//如果没有可显示的，则移除所有item
			m_visible_items.RemoveAll();
			m_pVisibleMap->RemoveAll();
			return;
		}
        
        CSize szOldView;
        szOldView.cx = m_tvItemLocator->GetTotalWidth();
        szOldView.cy = m_tvItemLocator->GetTotalHeight();
        
        VISIBLEITEMSMAP *pMapOld = m_pVisibleMap;
        m_pVisibleMap = new VISIBLEITEMSMAP;
        
        CRect rcClient = GetClientRect();
        CRect rcContainer=rcClient;
        rcContainer.MoveToXY(0,0);
        rcContainer.bottom=10000;
        
        int nOffset = m_tvItemLocator->Item2Position(hItem) - m_siVer.nPos;
        
        m_visible_items.RemoveAll();
        while(hItem != ITvAdapter::ITEM_NULL)
        {
            VISIBLEITEMSMAP::CPair *pFind = pMapOld->Lookup(hItem);
            ItemInfo ii;
			ii.nType = m_adapter->getViewType(hItem);
            if(pFind && pFind->m_value.nType == ii.nType)
            {//re use the previous item;
					ii = pFind->m_value;
					pMapOld->RemoveKey(hItem);
            }else
            {
                SList<SItemPanel *> *lstRecycle = m_itemRecycle.GetAt(ii.nType);
                if(lstRecycle->IsEmpty())
                {//创建一个新的列表项
                    ii.pItem = SItemPanel::Create(this,pugi::xml_node(),this);
                    ii.pItem->GetEventSet()->subscribeEvent(EventItemPanelClick::EventID,Subscriber(&STreeView::OnItemClick,this));
                    ii.pItem->GetEventSet()->subscribeEvent(EventItemPanelDbclick::EventID,Subscriber(&STreeView::OnItemDblClick,this));
                }else
                {
                    ii.pItem = lstRecycle->RemoveHead();
                }
                ii.pItem->SetItemIndex(hItem);
            }
            m_pVisibleMap->SetAt(hItem,ii);
            ii.pItem->SetVisible(TRUE);
            
            if(hItem == m_hSelected)
                ii.pItem->ModifyItemState(WndState_Check,0);
            else
                ii.pItem->ModifyItemState(0,WndState_Check);