Qt:地图浏览器

Qt:地图浏览器

2010-08-06 04:36

(源代码和界面之间有一些差异) 参照Linux窗口程序设计---Qt4精彩实例分析中P187的例39"地图浏览器"； 和实例不同的是，这里增加了地图的平移功能。在Qt的Demo中，通过setDragMode(QGraphicsView::ScrollHandDrag)即可实现平移，但是，如果需要mouseMoveEvent事件的话，这个方法就不可用，理由如下： /*gps.h*/ #include <QtGui> #include "_5waybutton.h" class Gps:public QGraphicsView {     Q_OBJECT public:     Gps();     ~Gps();     //     void mouseMoveEvent(QMouseEvent *event);     void mousePressEvent(QMouseEvent *event);     void mouseReleaseEvent(QMouseEvent *event);     void mouseDoubleClickEvent(QMouseEvent *event);     void wheelEvent(QWheelEvent *event);     //     void load_map();     void drawBackground(QPainter *painter, const QRectF &rect);     //     QGraphicsScene *scene;     QPixmap map;     _5WayButton *_5waybutton;     QSlider *slider_zoom;     QFrame *frame_coor;     QLabel *label_coor;     QLabel *label_latitude;     QLabel *label_parallel;     QPoint point_start;     //     int zoom;     int center_x;     int center_y; public slots:     void slot_zoom(int value);     void slot_up();     void slot_left();     void slot_right();     void slot_down();     void slot_center(); }; /*gps.cpp*/ #include "gps.h" Gps::Gps() {     setVerticalScrollBarPolicy(Qt::ScrollBarAlwaysOff);     setHorizontalScrollBarPolicy(Qt::ScrollBarAlwaysOff);     load_map();     scene=new QGraphicsScene();     scene->setSceneRect(-map.width()/2,-map.height()/2,map.width(),map.height());     scene->setItemIndexMethod(QGraphicsScene::NoIndex);     setScene(scene);     setRenderHint(QPainter::Antialiasing);     setCacheMode(QGraphicsView::CacheBackground);     //setViewportUpdateMode(QGraphicsView::BoundingRectViewportUpdate);     //setDragMode(QGraphicsView::ScrollHandDrag);     //setWindowTitle(QT_TRANSLATE_NOOP(QGraphicsView, "Colliding Mice"));     //     QLabel *label_zoomout=new QLabel(tr(" 放大"));     label_zoomout->setFont(QFont("Arial",12,QFont::Bold));     //     QLabel *label_zoomin=new QLabel(tr(" 缩小"));     label_zoomin->setFont(QFont("Arial",12,QFont::Bold));     //     slider_zoom=new QSlider();     slider_zoom->setOrientation(Qt::Vertical);     slider_zoom->setRange(1,400);     slider_zoom->setTickInterval(5);     slider_zoom->setValue(200);     slider_zoom->setFixedSize(40,400);     connect(slider_zoom,SIGNAL(valueChanged(int)),this,SLOT(slot_zoom(int)));     zoom=200;     //     center_x=0;     center_y=0;     //     frame_coor=new QFrame();     //     label_coor=new QLabel(tr("地理坐标"));     label_coor->setFont(QFont("Arial",10,QFont::Bold));     label_latitude=new QLabel(tr("纬度: "));     label_latitude->setFont(QFont("Arial",10,QFont::Bold));     label_parallel=new QLabel(tr("经度: "));     label_parallel->setFont(QFont("Arial",10,QFont::Bold));     //     QVBoxLayout *layout_frame=new QVBoxLayout();     layout_frame->addWidget(label_coor);     layout_frame->addWidget(label_latitude);     layout_frame->addWidget(label_parallel);     frame_coor->setLayout(layout_frame);     //     _5waybutton=new _5WayButton();     connect(_5waybutton->navibutton_up,SIGNAL(clicked()),this,SLOT(slot_up()));     connect(_5waybutton->navibutton_left,SIGNAL(clicked()),this,SLOT(slot_left()));     connect(_5waybutton->navibutton_right,SIGNAL(clicked()),this,SLOT(slot_right()));     connect(_5waybutton->navibutton_down,SIGNAL(clicked()),this,SLOT(slot_down()));     connect(_5waybutton->navibutton_center,SIGNAL(clicked()),this,SLOT(slot_center()));     //     QVBoxLayout *layout_zoom=new QVBoxLayout();     layout_zoom->addWidget(frame_coor);     layout_zoom->addWidget(_5waybutton);     layout_zoom->addWidget(label_zoomout);     layout_zoom->addWidget(slider_zoom);     layout_zoom->addWidget(label_zoomin);     layout_zoom->setSpacing(0);     //     QHBoxLayout *layout_main=new QHBoxLayout();     layout_main->addLayout(layout_zoom);     layout_main->addStretch();     layout_main->setSpacing(0);     setLayout(layout_main); } Gps::~Gps() { } void Gps::load_map() {     map.load(":/image/wuhan.jpg"); } void Gps::drawBackground(QPainter *painter, const QRectF &rect) {     painter->drawPixmap(int(sceneRect().left()),int(sceneRect().top()),map); } void Gps::slot_zoom(int value) {     qreal s;     if(value>zoom)     {         s=pow(1.01,(value-zoom));     }     else     {         s=pow((1/1.01),(zoom-value));     }     scale(s,s);     zoom=value; } void Gps::mouseMoveEvent(QMouseEvent *event) {     QPointF point_scene=this->mapToScene(event->pos());     label_latitude->setText(tr("纬度: ")+QString::number(point_scene.y()+map.height()/2));     label_parallel->setText(tr("经度: ")+QString::number(point_scene.x()+map.width()/2));     if(cursor().shape()==Qt::OpenHandCursor)     {         center_x+=5*(event->pos().x()-point_start.x());         center_x<-map.width()/2?center_x=-map.width()/2:1;         center_x>map.width()/2?center_x=map.width()/2:1;         center_y+=5*(event->pos().y()-point_start.y());         center_y<-map.height()/2?center_y=-map.height()/2:1;         center_y>map.height()/2?center_y=map.height()/2:1;         centerOn(center_x,center_y);         point_start=event->pos();     } } void Gps::mousePressEvent(QMouseEvent *event) {     point_start=event->pos();     setCursor(Qt::OpenHandCursor); } void Gps::mouseReleaseEvent(QMouseEvent *event) {     this->setCursor(Qt::ArrowCursor); } void Gps::mouseDoubleClickEvent(QMouseEvent *event) {     slot_center(); } void Gps::wheelEvent(QWheelEvent *event) {     int z=slider_zoom->value()+event->delta()/10;     z>400?z=400:1;     z<1?z=1:1;     this->slider_zoom->setValue(z); } void Gps::slot_up() {     center_y<-map.height()/2?center_y=-map.height()/2:center_y-=map.height()/10;     centerOn(center_x,center_y); } void Gps::slot_left() {     center_x<-map.width()/2?center_x=-map.width()/2:center_x-=map.width()/10;     centerOn(center_x,center_y); } void Gps::slot_right() {     center_x>map.width()/2?center_x=map.width()/2:center_x+=map.width()/10;     centerOn(center_x,center_y); } void Gps::slot_down() {     center_y>map.height()/2?center_y=map.height()/2:center_y+=map.height()/10;     centerOn(center_x,center_y); } void Gps::slot_center() {     slider_zoom->setValue(200);     center_x=0;     center_y=0;     centerOn(center_x,center_y

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