为什么graphicsView里不显示呀

MainWindow::MainWindow(QWidget *parent)

    : QMainWindow(parent)

    , ui(new Ui::MainWindow)

{

    ui->setupUi(this);

    myView = new Graphics_view_zoom(ui->graphicsView);

    myView->set_modifiers(Qt::NoModifier);

    ui->graphicsView->setRenderHint(QPainter::Antialiasing);

    scene=new QGraphicsScene;

    scene->setSceneRect(-LINE_INFO_WIDTH,0,SCENE_WIDTH,SCENE_HEIGHT);

    ui->graphicsView->setScene(scene);

    ui->graphicsView->setDragMode(QGraphicsView::ScrollHandDrag);

    busGraph=new BusGraph;

    busGraph->readFileData(":/data/data/outline.txt");

    myConnect();

    initBusLine();

    on_actionLineMap_triggered();

}

//绘制网络图的边

void MainWindow::drawEdges(myvector<edge>& edgesList)

{

    for(int i=0; i<edgesList.getlength(); ++i)

    {

        int s1=edgesList[i].s1;

        int s2=edgesList[i].s2;

        myvector<int> linesList=busGraph->getCommonLines(s1, s2);

        QColor color=getLinesColor(linesList);

        QString tip="途经： "+busGraph->getStationName(s1)+"--"+busGraph->getStationName(s2)+"\n线路：";

        tip+=getLinesName(linesList);

        QPointF s1Pos=transferCoord(busGraph->getStationCoord(s1));

        QPointF s2Pos=transferCoord(busGraph->getStationCoord(s2));

        QGraphicsLineItem* edgeItem=new QGraphicsLineItem;

        edgeItem->setPen(QPen(color, EDGE_PEN_WIDTH));

        edgeItem->setCursor(Qt::PointingHandCursor);

        edgeItem->setToolTip(tip);

        edgeItem->setPos(s1Pos);

        edgeItem->setLine(0, 0, s2Pos.x()-s1Pos.x(), s2Pos.y()-s1Pos.y());

        scene->addItem(edgeItem);

    }

}

//绘制网络图的站点节点

void MainWindow::drawStations (myvector<int>& stationsList)

{

    for (int i=0; i<stationsList.getlength(); ++i)

    {

        int s=stationsList[i];

        QString name=busGraph->getStationName(s);

        myvector<int> linesList=busGraph->getStationLinesInfo(s);

        QColor color=getLinesColor(linesList);

        QPointF longiLati=busGraph->getStationCoord(s);

        QPointF coord=transferCoord(longiLati);

        QString tip="站名：  "+name+"\n"+

                "经度：  "+QString::number(longiLati.x(),'f',7)+"\n"+

                "纬度：  "+QString::number(longiLati.y(),'f',7)+"\n"+

                "线路："+getLinesName(linesList);

        QGraphicsEllipseItem* stationItem=new QGraphicsEllipseItem;

        stationItem->setRect(-NODE_HALF_WIDTH, -NODE_HALF_WIDTH, NODE_HALF_WIDTH<<1, NODE_HALF_WIDTH<<1);

        stationItem->setPos(coord);

        stationItem->setPen(color);

        stationItem->setCursor(Qt::PointingHandCursor);

        stationItem->setToolTip(tip);

        if(linesList.getlength()<=1)

        {

            stationItem->setBrush(QColor(QRgb(0xffffff)));

        }

        scene->addItem(stationItem);

        QGraphicsTextItem* textItem=new QGraphicsTextItem;

        textItem->setPlainText(name);

        textItem->setFont(QFont("consolas",4,1));

        textItem->setPos(coord.x(),coord.y()-NODE_HALF_WIDTH*2);

        scene->addItem(textItem);

        qDebug()<<""<<textItem;

    }

}

//动作查看所有线路图槽函数

void MainWindow::on_actionLineMap_triggered()

{

    scene->clear();

    myvector<int> stationsList;

    myvector<edge> edgesList;

    busGraph->getGraph(stationsList,edgesList);

    drawEdges(edgesList);

    drawStations(stationsList);

}

代码看的难受