导航是地图类项目实战中经常会遇到了。看上去貌似没头绪，其实是有模板遵循的。我们直接根据图看代码。
//MainWidget.h
#ifndef MAINWINDOW_H
#define MAINWINDOW_H
#include <QMainWindow>
#include "mapwidget.h"
#include <QToolButton>
#include <QGraphicsLineItem>
#include <QGraphicsScene>
#include <QGraphicsView>
#include <QLabel>
#include <QComboBox>
#include <QSpinBox>
#include <QTextEdit>
#include <QPainter>
#include <QVector>
class MainWindow : public QMainWindow
{
Q_OBJECT
public:
MainWindow(QWidget *parent = 0);
~MainWindow();
void createToolBar();
void paintEvent (QPaintEvent *);
void setStart(int X, int Y);
void setEnd(int X, int Y);
void setNextPos (int index);
void initScene();
public slots:
void setStartStation();
void setEndStation();
void FindPath();
void Clear();
private:
MapWidget *mapWidget;
QLabel *startLabel;
QLabel *endLabel;
QComboBox *startComboBox;
QComboBox *endComboBox;
QToolButton *findPathBtn;
QToolButton *clearBtn;
QGraphicsScene *scene;
QGraphicsView *view;
int startX, startY, endX, endY;
QVector<int> nextPath;
struct ArcCell{ //弧信息
int adj; //对无权图有1，0表示是否相邻，对带权图，则为权值类型
// string info; //该弧的相关信息
};
//内部类
static const int MAX_VERTEX_NUM = 31;
static const int INF = 999999;
struct MGraph{
QVector<int> vexs; //顶点集合
//临接矩阵
ArcCell arcs[MAX_VERTEX_NUM][MAX_VERTEX_NUM];
int vexnum; //顶点数
int arcnum; //边数
// int kind; //图的类型
};
class DijkstraFindPath
{
public:
DijkstraFindPath();
MGraph mgraph;
void CreateGraph();
// void ShortestPath(int v0, PathMatrix &path, ShortPathTable &DP, int prev[]);
int prev[MAX_VERTEX_NUM]; //最短路上的前驱顶点
int d[MAX_VERTEX_NUM]; //表示边e = (u,v)的权值(不存在时为INF,不过d[i][i]=0)
bool used[MAX_VERTEX_NUM]; //已经使用过的图
void dijkstra(int startPos); //求从起点startPos出发到各个顶点的最短距离
QVector<int> get_Path(int endPos);//到顶点endPos的最短路
};
DijkstraFindPath *dj;
};
#endif // MAINWINDOW_H//MainWidget.cpp
//最短路径算法，和界面的实现
#include "mainwindow.h"
#include <qdebug.h>
#include <QToolBar>
#include <QtAlgorithms>
#include <iostream>
MainWindow::MainWindow(QWidget *parent)
: QMainWindow(parent)
{
// mapWidget = new MapWidget;
// painter = new QPainter();
dj = new MainWindow::DijkstraFindPath();
dj->CreateGraph ();
scene = new QGraphicsScene;
scene->setSceneRect (-100, -100, 700, 700);
initScene();
view = new QGraphicsView;
view->setScene (scene);
view->setMinimumSize (800, 800);
view->show ();
setCentralWidget (view);
createToolBar (); //实现一个工具栏
// setCentralWidget (mapWidget);
// setMinimumSize (600, 400); //设置最小尺寸
}
MainWindow::DijkstraFindPath::DijkstraFindPath()
{
mgraph.vexnum = 31; //初始化点数目
for (int i = 0; i < mgraph.vexnum; i++) //初始化点编号
mgraph.vexs.push_back (i);
mgraph.arcnum = 80; //暂定
for (int i = 0; i < mgraph.vexnum; i++) {
for (int j = 0; j < mgraph.vexnum; j++) {
if (i == j)
mgraph.arcs[i][j].adj = 0;
else
mgraph.arcs[i][j].adj = INF;
// mgraph.arcs[i][j].info = "";
}
}
}
void MainWindow::DijkstraFindPath::CreateGraph ()
{
mgraph.arcs[0][1].adj = mgraph.arcs[1][0].adj = 45; //6 - 5
mgraph.arcs[0][6].adj = mgraph.arcs[6][0].adj = 165; //6 - 10
mgraph.arcs[1][2].adj = mgraph.arcs[2][1].adj = 45; //5 - 4
mgraph.arcs[2][3].adj = mgraph.arcs[3][2].adj = 45; //4 - 3
mgraph.arcs[3][4].adj = mgraph.arcs[4][3].adj = 45; //3 - 2
mgraph.arcs[3][15].adj = mgraph.arcs[15][3].adj = 24; //3 - 22
mgraph.arcs[4][5].adj = mgraph.arcs[5][4].adj = 45; //2 - 1
mgraph.arcs[13][15].adj = mgraph.arcs[15][13].adj = 85;//23 - 22
mgraph.arcs[0][13].adj = mgraph.arcs[13][0].adj = 55; //6 - 23
mgraph.arcs[13][2].adj = mgraph.arcs[2][13].adj = 50; //23 - 4
mgraph.arcs[5][11].adj = mgraph.arcs[11][5].adj = 65; //1 - 一食堂
mgraph.arcs[11][12].adj = mgraph.arcs[12][11].adj = 10;//一食堂-操场
mgraph.arcs[11][27].adj = mgraph.arcs[27][11].adj = 85;//一食堂-祁通1
mgraph.arcs[27][28].adj = mgraph.arcs[28][27].adj = 85;//祁通1-祁通2(路口)
mgraph.arcs[5][29].adj = mgraph.arcs[29][5].adj = 87; //一食堂-岔路口
mgraph.arcs[29][9].adj = mgraph.arcs[9][29].adj = 80; //岔路-7
mgraph.arcs[29][11].adj = mgraph.arcs[11][29].adj = 60;//一食堂到岔路(通向7号楼的)
mgraph.arcs[29][30].adj = mgraph.arcs[30][29].adj = 32;//岔路-祁通大道
mgraph.arcs[30][10].adj = mgraph.arcs[10][30].adj = 90;//祁通大道-图书馆
mgraph.arcs[30][28].adj = mgraph.arcs[28][30].adj = 80;//祁通大道-祁通2
mgraph.arcs[28][26].adj = mgraph.arcs[26][28].adj = 15;//祁通2-方肇周
mgraph.arcs[25][27].adj = mgraph.arcs[27][25].adj = 273; //西大门-祁通1
mgraph.arcs[27][28].adj = mgraph.arcs[28][27].adj = 184;//祁通1-祁通2
// mgraph.arcs[25][12].adj = mgraph.arcs[12][25].adj = 108; //西大门-西操
mgraph.arcs[5][12].adj = mgraph.arcs[12][5].adj = 70; //1 - 操场
mgraph.arcs[6][7].adj = mgraph.arcs[7][6].adj = 45; //10 - 9
mgraph.arcs[7][8].adj = mgraph.arcs[8][7].adj = 45; //9 - 8
mgraph.arcs[8][9].adj = mgraph.arcs[9][8].adj = 45; //8 - 7
mgraph.arcs[9][10].adj = mgraph.arcs[10][9].adj = 150; //7 - 图书馆
mgraph.arcs[6][14].adj = mgraph.arcs[14][6].adj = 140; //10 - 13
mgraph.arcs[14][16].adj = mgraph.arcs[16][14].adj = 39;//13 - 12
mgraph.arcs[14][17].adj = mgraph.arcs[17][14].adj = 39;//13 - 16
mgraph.arcs[16][18].adj = mgraph.arcs[18][16].adj = 39;//12 - 15
mgraph.arcs[17][18].adj = mgraph.arcs[18][17].adj = 39;//16 - 15
mgraph.arcs[18][19].adj = mgraph.arcs[19][18].adj = 39;//15 - 14
mgraph.arcs[17][20].adj = mgraph.arcs[20][17].adj = 137;//16 - 19
mgraph.arcs[20][21].adj = mgraph.arcs[21][20].adj = 39; //19 - 18
mgraph.arcs[21][22].adj = mgraph.arcs[22][21].adj = 39; //18 - 17
mgraph.arcs[19][22].adj = mgraph.arcs[22][19].adj = 130;//14 - 17
mgraph.arcs[22][23].adj = mgraph.arcs[23][22].adj = 53; //17 - 二超
mgraph.arcs[23][24].adj = mgraph.arcs[24][23].adj = 5; //二超 - 二食堂
mgraph.arcs[24][10].adj = mgraph.arcs[10][24].adj = 260;//二食堂-图书馆
//以下处理细节
mgraph.arcnum = 80;
}
void MainWindow::DijkstraFindPath::dijkstra (int startPos)
{
for (int i = 0; i < mgraph.vexnum; i++) d[i] = INF;
for (int i = 0; i < mgraph.vexnum; i++) used[i] = false;
for (int i = 0; i < mgraph.vexnum; i++) prev[i] = -1;
d[startPos] = 0;
while (true) {
int v = -1;
for (int u = 0; u < mgraph.vexnum; u++) {
if (!used[u] && (v == -1 || d[u] < d[v])) v = u;
}
if (v == -1) break;
used[v] = true;
for (int u = 0; u < mgraph.vexnum; u++) {
if (d[u] > d[v] + mgraph.arcs[v][u].adj) {
d[u] = d[v] + mgraph.arcs[v][u].adj;
prev[u] = v;
}
}
}
}
QVector<int> MainWindow::DijkstraFindPath::get_Path (int endPos)
{
QVector<int> path;
for ( ; endPos != -1; endPos = prev[endPos]) {
// std::cout << "EndPos: " << endPos << ", ";
path.push_back (endPos);
}
std::reverse(path.begin (), path.end ());
return path;
}
void MainWindow::initScene ()
{
QGraphicsPixmapItem *item =
scene->addPixmap (QPixmap("NanTong.jpg"));
// item->setFlag (QGraphicsItem::ItemIsMovable);
item->setPos (-500, -420);
}
MainWindow::~MainWindow()
{
}
void MainWindow::createToolBar ()
{
QToolBar *toolBar = addToolBar ("Tool");
startLabel = new QLabel(tr("起点: "));
startComboBox = new QComboBox;
startComboBox->addItem (tr("公寓6号楼")); //0
startComboBox->addItem (tr("公寓5号楼")); //1
startComboBox->addItem (tr("公寓4号楼")); //2
startComboBox->addItem (tr("公寓3号楼")); //3
startComboBox->addItem (tr("公寓2号楼")); //4
startComboBox->addItem (tr("公寓1号楼")); //5
startComboBox->addItem (tr("公寓10号楼")); //6
startComboBox->addItem (tr("公寓9号楼")); //7
startComboBox->addItem (tr("公寓8号楼")); //8
startComboBox->addItem (tr("公寓7号楼")); //9
startComboBox->addItem (tr("图书馆")); //10
startComboBox->addItem (tr("一食堂")); startComboBox->addItem (tr("西操场")); //11 12
startComboBox->addItem (tr("公寓23号楼")); startComboBox->addItem (tr("公寓13号楼")); //13 14
startComboBox->addItem (tr("公寓22号楼")); startComboBox->addItem (tr("公寓12号楼")); //15 16
startComboBox->addItem (tr("公寓楼16")); startComboBox->addItem (tr("公寓楼15")); //17 18
startComboBox->addItem (tr("公寓楼14")); startComboBox->addItem (tr("公寓楼19")); //19 20
startComboBox->addItem (tr("公寓楼18")); startComboBox->addItem (tr("公寓楼17")); //21 22
startComboBox->addItem (tr("二超")); startComboBox->addItem (tr("二食堂")); //23 24
startComboBox->addItem (tr("西大门")); startComboBox->addItem (tr("方肇周教学楼")); //25 26
endLabel = new QLabel(tr("\t终点: "));
endComboBox = new QComboBox;
endComboBox->addItem (tr("公寓6号楼"));
endComboBox->addItem (tr("公寓5号楼"));
endComboBox->addItem (tr("公寓4号楼"));
endComboBox->addItem (tr("公寓3号楼"));
endComboBox->addItem (tr("公寓2号楼"));
endComboBox->addItem (tr("公寓1号楼"));
endComboBox->addItem (tr("公寓10号楼"));
endComboBox->addItem (tr("公寓9号楼"));
endComboBox->addItem (tr("公寓8号楼"));
endComboBox->addItem (tr("公寓7号楼"));
endComboBox->addItem (tr("图书馆"));
endComboBox->addItem (tr("一食堂")); endComboBox->addItem (tr("西操场"));
endComboBox->addItem (tr("公寓23号楼"));endComboBox->addItem (tr("公寓13号楼"));
endComboBox->addItem (tr("公寓22号楼"));endComboBox->addItem (tr("公寓12号楼"));
endComboBox->addItem (tr("公寓楼16")); endComboBox->addItem (tr("公寓楼15"));
endComboBox->addItem (tr("公寓楼14")); endComboBox->addItem (tr("公寓楼19"));
endComboBox->addItem (tr("公寓楼18")); endComboBox->addItem (tr("公寓楼17"));
endComboBox->addItem (tr("二超")); endComboBox->addItem (tr("二食堂"));
endComboBox->addItem (tr("西大门")); endComboBox->addItem (tr("方肇周教学楼"));
connect (startComboBox, SIGNAL(activated(int)), this, SLOT(setStartStation()));
connect (endComboBox, SIGNAL(activated(int)), this, SLOT(setEndStation()));
findPathBtn = new QToolButton;
findPathBtn->setText (tr("\t\t绘制最短路径"));
connect (findPathBtn, SIGNAL(clicked(bool)), this, SLOT(FindPath()));
clearBtn = new QToolButton;
clearBtn->setText (tr("\t\t清除"));
connect (clearBtn, SIGNAL(clicked(bool)), this, SLOT(Clear()));
toolBar->addWidget (startLabel);
toolBar->addWidget (startComboBox);
toolBar->addWidget (endLabel);
toolBar->addWidget (endComboBox);
toolBar->addWidget (findPathBtn);
toolBar->addWidget (clearBtn);
}
void MainWindow::setStart(int X, int Y) {
startX = X; startY = Y;
// qDebug() << X << ", " << Y;
}
void MainWindow::setEnd (int X, int Y)
{
endX = X; endY = Y;
}
void MainWindow::setStartStation ()
{
switch (startComboBox->currentIndex ()) {
case 0:
setStart(-660, -534); break;
case 1:
setStart (-673, -490); break;
case 2:
setStart (-682, -446); break;
case 3:
setStart (-690, -400); break;
case 4:
setStart (-701, -355); break;
case 5:
setStart (-711, -310); break;
case 6:
setStart (-457, -555); break;
case 7:
setStart (-449, -485); break;
case 8:
setStart(-446, -432); break;
case 9:
setStart (-451, -400); break;
case 10:
setStart (-347, -353); break;
case 11:
setStart (-720, -247); break;
case 12:
setStart (-789, -252); break;
case 13:
setStart (-721, -517); break;
case 14:
setStart (-271, -540); break;
case 15:
setStart (-721, -439); break;
case 16:
setStart (-274, -495); break;
case 17:
setStart (-180, -552); break;
case 18:
setStart (-178, -508); break;
case 19:
setStart (-179, -456); break;
case 20:
setStart (-73, -549); break;
case 21:
setStart (-56, -500); break;
case 22:
setStart (-59, -448); break;
case 23:
setStart (-94, -381); break;
case 24:
setStart (-69, -351); break;
case 25:
setStart (-1070, -92); break;
case 26:
setStart (-438, -125); break;
case 27:
setStart (-721, -119); break;
case 28:
setStart (-550, -122); break;
case 29:
setStart (-555, -263); break;
case 30:
setStart (-498, -235); break;
default:
break;
}
}
void MainWindow::setEndStation ()
{
switch (endComboBox->currentIndex ()) {
case 0:
setEnd(-660, -534); break;
case 1:
setEnd (-673, -490); break;
case 2:
setEnd (-682, -446); break;
case 3:
setEnd (-690, -400); break;
case 4:
setEnd (-701, -355); break;
case 5:
setEnd (-711, -310); break;
case 6:
setEnd (-457, -555); break;
case 7:
setEnd (-449, -485); break;
case 8:
setEnd (-446, -432); break;
case 9:
setEnd (-451, -400); break;
case 10:
setEnd (-347, -353); break;
case 11:
setEnd (-720, -247); break;
case 12:
setEnd (-789, -252); break;
case 13:
setEnd (-721, -517); break;
case 14:
setEnd (-271, -540); break;
case 15:
setEnd (-721, -439); break;
case 16:
setEnd (-274, -495); break;
case 17:
setEnd (-180, -552); break;
case 18:
setEnd (-178, -508); break;
case 19:
setEnd (-179, -456); break;
case 20:
setEnd (-73, -549); break;
case 21:
setEnd (-56, -500); break;
case 22:
setEnd (-59, -448); break;
case 23:
setEnd (-94, -381); break;
case 24:
setEnd (-69, -351); break;
case 25:
setEnd (-1070, -92); break;
case 26:
setEnd (-438, -125); break;
case 27:
setEnd (-721, -119); break;
case 28:
setEnd (-550, -122); break;
case 29:
setEnd (-555, -263); break;
case 30:
setEnd (-498, -235); break;
default:
break;
}
}
void MainWindow::setNextPos (int index)
{
switch (index) {
case 0:
setEnd(-660, -534); break;
case 1:
setEnd (-673, -490); break;
case 2:
setEnd (-682, -446); break;
case 3:
setEnd (-690, -400); break;
case 4:
setEnd (-701, -355); break;
case 5:
setEnd (-711, -310); break;
case 6:
setEnd (-457, -555); break;
case 7:
setEnd (-449, -485); break;
case 8:
setEnd (-446, -432); break;
case 9:
setEnd (-451, -400); break;
case 10:
setEnd (-347, -353); break;
case 11:
setEnd (-720, -247); break;
case 12:
setEnd (-789, -252); break;
case 13:
setEnd (-721, -517); break;
case 14:
setEnd (-271, -540); break;
case 15:
setEnd (-721, -439); break;
case 16:
setEnd (-274, -495); break;
case 17:
setEnd (-180, -552); break;
case 18:
setEnd (-178, -508); break;
case 19:
setEnd (-179, -456); break;
case 20:
setEnd (-73, -549); break;
case 21:
setEnd (-56, -500); break;
case 22:
setEnd (-59, -448); break;
case 23:
setEnd (-94, -381); break;
case 24:
setEnd (-69, -351); break;
case 25:
setEnd (-1070, -92); break;
case 26:
setEnd (-438, -125); break;
case 27:
setEnd (-721, -119); break;
case 28:
setEnd (-550, -122); break;
case 29:
setEnd (-555, -263); break;
case 30:
setEnd (-498, -235); break;
default:
break;
}
}
void MainWindow::FindPath ()
{
//Demo 在图片上绘线 在原有基础上 (+700, +440);
QVector<QPoint> v;
dj->dijkstra (startComboBox->currentIndex ());
//设置下一处的终点
nextPath = dj->get_Path (endComboBox->currentIndex ());
//准备绘制
Clear ();
//将路线绘制下来
QGraphicsPathItem *item = new QGraphicsPathItem();
QPen pen;
pen.setWidth (4);
pen.setColor (Qt::red);
item->setPen (pen);
item->setFlag (QGraphicsItem::ItemIsPanel);
// qDebug() << startX << " " << startY << " " << endX << " " << endY;
// qDebug() << "Hello World !";
//设置起点
// v << QPoint(startX + 700, startY + 440);
for (int i = 1; i < nextPath.size (); i++) {
qDebug() << nextPath[i] << " , ";
}
scene->addItem (item);
QPainterPath pa; //path
// setNextPos (nextPath[1]);
// item->setLine (startX + 700, startY + 440, endX + 700, endY + 440);
pa.moveTo (startX + 700, startY + 440);
for (int i = 1; i < nextPath.size() ; i++) {
setNextPos (nextPath[i]);
pa.lineTo (endX + 700, endY + 440);
}
item->setPath (pa);
}
void MainWindow::Clear ()
{
QList<QGraphicsItem*> listItem = scene->items ();
while (!listItem.empty ())
{
scene->removeItem (listItem.at (0));
listItem.removeAt (0);
}
QGraphicsPixmapItem *item =
scene->addPixmap (QPixmap("NanTong.jpg"));
// item->setFlag (QGraphicsItem::ItemIsMovable);
item->setPos (-500, -420);
}
void MainWindow::paintEvent (QPaintEvent *)
{
}下面是main主函数调用。
//Main.cpp
#include "mainwindow.h"
#include "mapwidget.h"
#include <QApplication>
#include <QFont>
#include <QDebug>
int main(int argc, char *argv[])
{
QApplication a(argc, argv);
QFont font("ARPL KaitiM GB", 12);
font.setBold (true);
a.setFont (font);
qDebug() << "Run............";
MainWindow w;
w.show ();
return a.exec();
}end
