Qt QGraphicsScene繪圖節點保存及恢復

在上一篇文章中 Qt 遍歷不規則樹的節點，介紹了節點保存及恢復，但是恢復時不是將原有節點原樣恢復。這里介紹怎樣恢復原樣。

思路：要恢復恢復，首先肯定要有節點的坐標（在scene中）。節點恢復后，還要使用箭頭連接。據此，我們保存時，要保存節點坐標，及箭頭首尾節點。根據上一篇文章，我們在創建時已經給節點了唯一標識。

唯一標識代碼：

QString getGUID()
{
    QUuid id = QUuid::createUuid();
    QString strId = id.toString();
    return strId;
}

保存函數及說明如下：

bool OperateItemFile::SaveItemArrowFile(QList<DiagramItem *> &pItemList, QList<Arrow *> &pArrowList, QString itFilePath)
{
    if(pItemList.size() > 0){
        QDomDocument doc;
        doc.appendChild( doc.createProcessingInstruction("xml", XML_HEAD_INFO));
        QFile file(itFilePath);
        if (!file.open(QIODevice::WriteOnly)){
            return false;
        }
        QDomElement root = doc.createElement("Root");
        doc.appendChild(root);
        //設備節點
        QDomElement dev = doc.createElement("DeviceVerb");
        root.appendChild(dev);
        for(int i=0 ;i<pItemList.size() ;i++){
            QDomElement ItemE = doc.createElement("Device");
            ItemE.setAttribute("ItemId" ,pItemList.at(i)->getItemId());
            ItemE.setAttribute("left" ,pItemList.at(i)->boundingRect().left());
            ItemE.setAttribute("top" ,pItemList.at(i)->boundingRect().top());
            ItemE.setAttribute("right" ,pItemList.at(i)->boundingRect().right());
            ItemE.setAttribute("bottom" ,pItemList.at(i)->boundingRect().bottom());
            ItemE.setAttribute("name" ,pItemList.at(i)->getText());
            ItemE.setAttribute("x" ,pItemList.at(i)->pos().x());
            ItemE.setAttribute("y" ,pItemList.at(i)->pos().y());
            ItemE.setAttribute("z" ,pItemList.at(i)->zValue());
            ItemE.setAttribute("color" ,pItemList.at(i)->brush().color().rgb());
            ItemE.setAttribute("brushstyle" ,pItemList.at(i)->brush().style());
            ItemE.setAttribute("type" ,pItemList.at(i)->diagramType());
            getItemChild(pItemList, pItemList.at(i), doc, ItemE);
            dev.appendChild(ItemE);
        }

        //保存箭頭
        if(pArrowList.size() > 0){
            QDomElement arrow = doc.createElement("ArrowVerb");
            root.appendChild(arrow);
            for(int i=0 ;i<pArrowList.size() ;i++){
                QDomElement ArrowItem = doc.createElement("Arrow");
                ArrowItem.setAttribute("StartItemId" ,pArrowList.at(i)->getStartId());
                ArrowItem.setAttribute("EndItemId" ,pArrowList.at(i)->getEndId());
                arrow.appendChild(ArrowItem);
            }
        }

        QString xml = doc.toString();
        QTextStream txtOutput(&file);
        txtOutput.setCodec("UTF-8");
        txtOutput<<xml;
        file.close();
    }
    return true;
}

　　函數中的參數依次是：所有節點，所有箭頭，及保存的文件名。

恢復函數如下：

bool OperateItemFile::getNormalItem(QString itemType, QList<DiagramItem *> *pList, QDomNodeList &domList, QMenu *itemMenu)
{
    for (int i = 0; i < domList.size(); i++) {
        QStringList szAttrVal;
        QDomElement fileElem = domList.at(i).toElement();
        QString l = fileElem.attribute("left");
        QString t = fileElem.attribute("top");
        QString r = fileElem.attribute("right");
        QString b = fileElem.attribute("bottom");
        QString name = fileElem.attribute("name");
        QString id = fileElem.attribute("ItemId");
        QString x = fileElem.attribute("x");
        QString y = fileElem.attribute("y");
        QString z = fileElem.attribute("z");
        QString type = fileElem.attribute("type");
        QString rgb = fileElem.attribute("color");
        QString brushstyle = fileElem.attribute("brushstyle");

        DiagramItem* pItem = new DiagramItem((DiagramItem::DiagramType)type.toUInt() ,itemMenu);
        pItem->setPos(QPointF(x.toFloat() ,y.toFloat()));
        pItem->setZValue(z.toFloat());
        pItem->setBkColor(QColor(rgb.toUInt()));
        pItem->setItemId(id);
        pItem->setText(name);
        pItem->setBrush(QBrush(rgb.toUInt(),  (Qt::BrushStyle)brushstyle.toUInt()));
        if(itemType.compare("Port") == 0)
        {
            QString parentItemId = fileElem.attribute("parentItemId");
            pItem->setParentItemId(parentItemId);
        }
        szAttrVal.push_back(name);
        szAttrVal.push_back(rgb);
        szAttrVal.push_back("False");
        szAttrVal.push_back("");
        szAttrVal.push_back("");
        szAttrVal.push_back("");
        szAttrVal.push_back("");
        for (int j = 0; j < szAttrName.size(); j++) {
            pItem->setItemAttr(j, szAttrName.at(j), szAttrVal.at(j));
        }

        pList->push_back(pItem);
    }
    return true;
}

bool OperateItemFile::GetItemArrowFromFile(QString strItemPath, QList<DiagramItem *> *pItemList, QList<Arrow *> *pArrowList, QMenu *itemMenu)
{
    if(strItemPath.length() <= 0 || pItemList == NULL || pArrowList == NULL)
        return false;

    QDomDocument doc;
    QFile file(strItemPath);
    if (!file.open(QIODevice::ReadOnly)){
        return false;
    }
    if (!doc.setContent(&file))
    {
        file.close();
        return false;
    }
    QDomNodeList listNormalItem = doc.elementsByTagName("Device");
    QDomNodeList listPortItem = doc.elementsByTagName("Port");
    QDomNodeList listArrow = doc.elementsByTagName("Arrow");

    getNormalItem("Item", pItemList, listNormalItem, itemMenu);
    getNormalItem("Port", pItemList, listPortItem, itemMenu);

    for (int i = 0; i < listArrow.size(); i++) {
        QDomElement arrowEle = listArrow.at(i).toElement();
        QString sid = arrowEle.attribute("StartItemId");
        QString eid = arrowEle.attribute("EndItemId");
        Arrow* pItem = new Arrow(NULL ,NULL);
        pItem->setItemId(sid,eid);
        pArrowList->push_back(pItem);
    }

    file.close();
    return true;
}

bool OperateItemFile::loadItemToScene(DiagramScene* pScene, bool bIsDialog, QString srcPath)
{
    if(!pScene) return false;

    QList<DiagramItem*> itemList;
    QList<Arrow*> ArrowList;

    QString strName;
    if(bIsDialog)
        strName = QFileDialog::getOpenFileName(nullptr, QObject::tr("open xml file"), p_globalObject->ProjectPath() + "/" + p_globalObject->getProjectName() ,QObject::tr("XML文件(*XML*)"));
    else
        strName = srcPath;

    ////////////////////////////////////////////////////////////////////////////////////
    if(!GetItemArrowFromFile(srcPath, &itemList, &ArrowList, NULL))
        return false;

        pScene->ItemClear();

        int i=0;
        for(i=0 ;i<itemList.size() ;i++){
            //itemList.at(i)->setBrush(pScene->itemColor());
            pScene->addItem(itemList.at(i));
        }
        pScene->setMode(DiagramScene::Mode::MoveItem);

        //設置箭頭起始節點
        int j=0;
        for(i=0 ;i<ArrowList.size(); i++){
            for(j=0 ;j<itemList.size() ;j++){
                if(ArrowList.at(i)->getStartId() == itemList.at(j)->getItemId()){
                    ArrowList.at(i)->setStartItem(itemList.at(j));
                    break;
                }
            }
        }
        //設置箭頭結尾節點
        for(i=0 ;i<ArrowList.size(); i++){
            for(j=0 ;j<itemList.size() ;j++){
                if(ArrowList.at(i)->getEndId() == itemList.at(j)->getItemId()){
                    ArrowList.at(i)->setEndItem(itemList.at(j));
                    break;
                }
            }
        }

        for(i=0 ;i<ArrowList.size() ;i++){
            if(ArrowList.at(i)->startItem()!=NULL)
                ArrowList.at(i)->startItem()->addArrow(ArrowList.at(i));

            if(ArrowList.at(i)->endItem()!=NULL)
                ArrowList.at(i)->endItem()->addArrow(ArrowList.at(i));

            ArrowList.at(i)->setColor(pScene->lineColor());
            ArrowList.at(i)->setZValue(-1000.0);
            pScene->addItem(ArrowList.at(i));
            if(p_globalObject->getCurStatus() == QGlobalObject::devStatus)
                ArrowList.at(i)->setArrowFlag(true);
            else
                ArrowList.at(i)->setArrowFlag(true);
            ArrowList.at(i)->updatePosition();
        }

    return true;
}

　　

getNormalItem函數中的type，區分是不是子節點。loadItemToScene 的參數bIsDialog,來確定是否顯示文件對話框。

 

Qt 遍歷不規則樹的節點