QT drawing network topology diagram (connecting database, recursive function, infinite drawing, dragging nodes)

Hardware ：ThinkPadT590

System ：Win10

database ：sqlserver2014

Qt：5.14.1

QtCreator：4.11.1

Source connection ：

qt Draw network topology diagram ( Connect to database , Recursive function , Infinite drawing , Drag nodes ）-QT Document resources -CSDN download qt To achieve the drawing of network topology diagram , Connect first sqlserver The database obtains all node data , Then, each more download resources are parsed through recursive functions 、 For learning materials, please visit CSDN Download channel .https://download.csdn.net/download/weixin_43935474/85868401

qt To achieve the drawing of network topology diagram , Connect first sqlserver The database obtains all node data , Then the relationship between each node is resolved by recursive function , And calculate the position of each node to be drawn on the graph , Then by rewriting

QGraphicsPixmapItem Class to draw a node graph , By rewriting 

QGraphicsItem Class to draw the line between nodes .

 As long as the relationship data between nodes is correct , You can draw infinitely .

The interface is as follows ：

  The dragging effect is as follows ：

 sqlserver The data in the database table is as follows ：

  The key codes are as follows ： 

#include <QtWidgets>
#include "nodeframe.h"

#include <iostream>
using namespace std;

NodeFrame::NodeFrame(QWidget *parent) :
    QGraphicsView(parent)
{   
    setGeometry(0,0,1920,2000);
    m_scene = new QGraphicsScene(0, 0, this->width(), this->height());
    this->setScene(m_scene);
    QScrollBar *horBar = this->horizontalScrollBar();
    QScrollBar *verBar = this->verticalScrollBar();
    horBar->setValue(horBar->maximum());
    verBar->setValue(verBar->maximum());
//    connectSqlServer();// Connect to the database and read the data , Disable here first , If you have a good database , You can drive 
    manulInitNoteList();// If you do not connect to the database, you can manually initialize the node queue , When connecting to the database , This line should be disabled ！
    initNodeList();
}

void NodeFrame::manulInitNoteList()
{
    NodeInSql node;
    node.nNodeID =1;    node.nParentID =1;    node.strNodeName =" The root node ";    m_lstNodeInSql.append(node);
    node.nNodeID =2;    node.nParentID =1;    node.strNodeName =" Child node 2";    m_lstNodeInSql.append(node);
    node.nNodeID =3;    node.nParentID =1;    node.strNodeName =" Child node 3";    m_lstNodeInSql.append(node);
    node.nNodeID =4;    node.nParentID =1;    node.strNodeName =" Child node 4";    m_lstNodeInSql.append(node);
    node.nNodeID =5;    node.nParentID =1;    node.strNodeName =" Child node 5";    m_lstNodeInSql.append(node);
    node.nNodeID =6;    node.nParentID =2;    node.strNodeName =" Child node 6";    m_lstNodeInSql.append(node);
    node.nNodeID =7;    node.nParentID =2;    node.strNodeName =" Child node 7";    m_lstNodeInSql.append(node);
    node.nNodeID =8;    node.nParentID =3;    node.strNodeName =" Child node 8";    m_lstNodeInSql.append(node);
    node.nNodeID =9;    node.nParentID =3;    node.strNodeName =" Child node 9";    m_lstNodeInSql.append(node);
    node.nNodeID =10;    node.nParentID =4;    node.strNodeName =" Child node 10";    m_lstNodeInSql.append(node);
    node.nNodeID =11;    node.nParentID =10;    node.strNodeName =" Child node 11";    m_lstNodeInSql.append(node);
    node.nNodeID =12;    node.nParentID =11;    node.strNodeName =" Child node 12";    m_lstNodeInSql.append(node);
    node.nNodeID =13;    node.nParentID =12;    node.strNodeName =" Child node 13";    m_lstNodeInSql.append(node);
    node.nNodeID =14;    node.nParentID =13;    node.strNodeName =" Child node 14";    m_lstNodeInSql.append(node);
    node.nNodeID =15;    node.nParentID =13;    node.strNodeName =" Child node 15";    m_lstNodeInSql.append(node);
    node.nNodeID =16;    node.nParentID =13;    node.strNodeName =" Child node 16";    m_lstNodeInSql.append(node);
    node.nNodeID =17;    node.nParentID =13;    node.strNodeName =" Child node 17";    m_lstNodeInSql.append(node);
    node.nNodeID =18;    node.nParentID =13;    node.strNodeName =" Child node 18";    m_lstNodeInSql.append(node);
}
NodeFrame::~NodeFrame()
{
    delete m_scene;
}


void NodeFrame::refresh()
{
    this->destroyed(m_scene);
    m_scene = new QGraphicsScene(0, 0, this->width(), this->height());
    this->setScene(m_scene);
    initNodeList();
}

void NodeFrame::connectSqlServer()
{
    QSqlDatabase db= QSqlDatabase::addDatabase("QODBC", "dbTemp");
    db.setDatabaseName(QString("DRIVER={SQL SERVER};"
                               "SERVER=%1;" // Server name 
                               "DATABASE=%2;"// Database name 
                               "UID=%3;"           // Login name 
                               "PWD=%4;"        // password 
                               ).arg("127.0.0.1,49674")// The port number on my computer is 49674
                       .arg("myTestSql")
                       .arg("Bruce")
                       .arg("Qwerty*963.-+")
                       );
    // Database connection 
    bool ok = db.open();
    if(ok)
    {
        qDebug()<<"database open success";
    }
    else
    {
        qDebug()<<db.lastError();
        return;
    }
    // Database query 
    QSqlQuery query(db);
    query.exec("SELECT * FROM Node;");
    while(query.next())
    {
        NodeInSql node;
        if(query.value(1).isValid())
            node.nNodeID = query.value(1).toInt();
        if(query.value(2).isValid())
            node.nParentID = query.value(2).toInt();
        if(query.value(3).isValid())
            node.strNodeName = query.value(3).toString();
        m_lstNodeInSql.append(node);
    }
    db.close();
}


void NodeFrame::initNodeList()
{
    // Find the root node 
    NodeInSql nRootID;
    foreach(NodeInSql node,m_lstNodeInSql)
    {
        if(node.nNodeID==node.nParentID)
        {
            nRootID = node;
        }
    }
    NodeInfoToShow rootNodeInfoToShow;
    rootNodeInfoToShow.nLevel = 0;
    rootNodeInfoToShow.nNodeID = nRootID.nNodeID;
    rootNodeInfoToShow.nParentID = nRootID.nParentID;
    rootNodeInfoToShow.ptPos = QPoint(0,100);
    rootNodeInfoToShow.strNodeName = nRootID.strNodeName;
    m_lstNodeInfoToShow.append(rootNodeInfoToShow);
    NetNode *rootNetNode = new NetNode(rootNodeInfoToShow,m_scene);
    parseNodesInSql(rootNodeInfoToShow,rootNetNode);// Analyze all node relationships and locations 
}
void NodeFrame::parseNodesInSql(NodeInfoToShow node,NetNode *netNode)
{
    int nChildNum = 0;// At present node A node has several child nodes 
    int nWidth = node.nLevel%2==0?250:150;// Horizontal spacing between nodes 
    int nHeight = 200;// Longitudinal spacing between nodes 
    QList<NodeInfoToShow> lstNodeInCrtLevel;// At present node All nodes under 
    for(int i = 0;i<m_lstNodeInSql.count();i++)
    {
        if(m_lstNodeInSql[i].nParentID==node.nNodeID && m_lstNodeInSql[i].nParentID!=m_lstNodeInSql[i].nNodeID)
        {
            nChildNum++;
            NodeInfoToShow rootNodeInfoToShow;
            rootNodeInfoToShow.nLevel = node.nLevel+1;
            rootNodeInfoToShow.nNodeID = m_lstNodeInSql[i].nNodeID;
            rootNodeInfoToShow.nParentID = node.nNodeID;
            rootNodeInfoToShow.ptPos = QPoint(0,0);// Here first 0,0 Point as initial value , Next, determine the location of each child node 
            rootNodeInfoToShow.strNodeName = m_lstNodeInSql[i].strNodeName;
            lstNodeInCrtLevel.append(rootNodeInfoToShow);
        }
    }
    // Determine the location of each child node 
    for(int i = 0;i<lstNodeInCrtLevel.count();i++)
    {
        if(nChildNum%2==1)// There are odd child nodes 
        {
            int nHalf = (nChildNum-1)/2;
            int nX =node.ptPos.x()+(i-nHalf)*nWidth;// Of the above node x Based on coordinates plus offset 
            int nY = node.ptPos.y()+nHeight;// Of the above node y Based on coordinates plus offset 
            lstNodeInCrtLevel[i].ptPos = QPoint(nX,nY);
        }
        else// There are even child nodes 
        {
            int nHalf = nChildNum/2;
            int nX =node.ptPos.x()+(i-nHalf)*nWidth+nWidth/2;// Of the above node x Based on coordinates plus offset 
            int nY = node.ptPos.y()+nHeight;// Of the above node y Based on coordinates plus offset 
            lstNodeInCrtLevel[i].ptPos = QPoint(nX,nY);
        }
        m_lstNodeInfoToShow.append(lstNodeInCrtLevel[i]);
        NetNode *subNetNode = new NetNode(lstNodeInCrtLevel[i],m_scene);
        NodeLink *link = new NodeLink(netNode, subNetNode);
        if (link) {
            m_scene->addItem(link);
        }
        parseNodesInSql(lstNodeInCrtLevel[i],subNetNode);
    }
}

Source download connection ：

qt Draw network topology diagram ( Connect to database , Recursive function , Infinite drawing , Drag nodes ）-QT Document resources -CSDN download qt To achieve the drawing of network topology diagram , Connect first sqlserver The database obtains all node data , Then, each more download resources are parsed through recursive functions 、 For learning materials, please visit CSDN Download channel .https://download.csdn.net/download/weixin_43935474/85868401