应大家的要求，还是把完整的project文件贴出来，大家省点事：http://www.kuaipan.cn/file/id_48923272389086450.htm
先看看执行效果，我用的群创7寸屏，主机是mini2440，分辨率是800*480，程序写比較粗糙，但对刚開始学习的人还是有一点启示，大家一起进步。
qt中提供了QGphicsView，QGraphicsScene，QGraphicsItem，QGraphicsPixmapItem是QGraphicsItem的子类
分辨创建它们的实例：view，scene，item，然后通过各自的方法scene->addItem(item);view->setScene(scene);就能够达到类似下图的效果，想要进一步定制，则要继承QGraphicsItem或QGraphicsPixmapItem，然后重写paint()、boundingRect()等方法，此外假设还想要获取鼠标事件，重写mousePressEvent等事件就好了，注意，一旦重写了mousePressEvent方法，就以为了qt不会再自己主动处理item的不论什么press事件了，能够在你重写的mousePressEvent方法中最后加入�QGraphicsItem::mousePressEvent(event);解决问题，就是说你获取到了鼠标事件，可是依旧让qt处理这个鼠标事件。
程序中的item能够水平拖动，拖动的同一时候图标大小会渐变，中间最大，两边渐小。
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以下是源程序文件夹结构：
mainwindow.h与main.cpp是qt自己主动产生的代码，我没有产生窗体ui
myscene.h与某与scene.cpp是定义了类MyScene，继承自QGraphicsScene，我的目的是要获取其鼠标事件
nodeui.h与nodeui.cpp是定义了类NodeUI，继承自QGraphicsPixmapItem，目的相当多。
以下详细的源文件：myscene.h与myscene.cpp相对简单，就实现了一个功能
myscene.h
#ifndef MYSCENE_H
#define MYSCENE_H#include <QGraphicsScene>class MyScene : public QGraphicsScene
{
Q_OBJECT
public:explicit MyScene(QObject *parent = 0);private:void mouseMoveEvent(QGraphicsSceneMouseEvent *event);void mousePressEvent(QGraphicsSceneMouseEvent *event);void mouseReleaseEvent(QGraphicsSceneMouseEvent *event);signals:void isMoving(QPointF &pos);public slots:private:QPointF beforePos;QPointF releasePos;
};#endif // MYSCENE_H
myscene.cpp
#include "myscene.h"
#include <QGraphicsSceneMouseEvent>
#include <QPointF>
#include <QDebug>MyScene::MyScene(QObject *parent) :QGraphicsScene(parent)
{
}
void MyScene::mouseMoveEvent(QGraphicsSceneMouseEvent *event)
{//QPointF pos = event->scenePos();QPointF pos(event->scenePos().x()-beforePos.x(),event->scenePos().y()-beforePos.y());emit isMoving(pos);//qDebug()<<"x:"<<pos.x()<<"y:"<<pos.y();
}
void MyScene::mousePressEvent(QGraphicsSceneMouseEvent *event)
{beforePos = event->scenePos();
}
void MyScene::mouseReleaseEvent(QGraphicsSceneMouseEvent *event)
{releasePos = event->scenePos();
}
再看nodeui.h与nodeui.cpp，在原来的QGraphicsPixmapItem基础上又假如了点自己的东西
#ifndef NODEUI_H
#define NODEUI_H#include <QGraphicsPixmapItem>
#include <QGraphicsItem>
#include <QStyleOptionGraphicsItem>
#include <QPainter>
#include <QGraphicsSceneMouseEvent>
#include <QPointF>class NodeUI : public QObject,public QGraphicsPixmapItem
{Q_OBJECT
public:NodeUI();NodeUI(QString &file,QString &text,int imagesize=80);//setup functionvoid setMyPixmap(QString &file,int size);void setMyText(QString &text);QString getMyText();//virtual functionQRectF boundingRect() const;QPainterPath shape() const;
signals:void nodeIsMoving(QPointF &pos);void nodeIsPressed();protected:void mousePressEvent(QGraphicsSceneMouseEvent *event);void mouseReleaseEvent(QGraphicsSceneMouseEvent *event);
private://QString myImage;QString myText;};#endif // NODEUI_Hnideui.cpp
#include "nodeui.h"
#include <QPixmap>
#include <iostream>
#include <QDebug>NodeUI::NodeUI()
{
}
/*note: imagesize = 80 is in the nodeui.h*/
NodeUI::NodeUI(QString &file,QString &text,int imagesize)
{setMyText(text);setMyPixmap(file,imagesize);
}void NodeUI::setMyText(QString &text)
{myText = text;
}void NodeUI::setMyPixmap(QString &file,int size)
{//myImage = file;QPixmap pixmap;pixmap.load(file);pixmap= pixmap.scaled(size,size,Qt::IgnoreAspectRatio, Qt::SmoothTransformation);setPixmap(pixmap);
}
QRectF NodeUI::boundingRect() const
{QRect rect = this->pixmap().rect();//return QRectF(rect);return QRectF(0,0,rect.width(),rect.width()+15);
}void NodeUI::paint(QPainter *painter, const QStyleOptionGraphicsItem *option,QWidget *widget)
{QPixmap pixmap = this->pixmap();QRect rect = pixmap.rect();painter->drawPixmap(rect,pixmap);//print name,calculate the text's heigh & width for center layoutQPen pen(Qt::black);painter->setPen(pen);painter->setRenderHint(QPainter::Antialiasing);QFont font("Verdana",8, QFont::Normal);painter->setFont(font);painter->drawText(QRectF(0,rect.height(),rect.width(),15),Qt::AlignCenter,myText);if (option->state & QStyle::State_Sunken){QRectF rect1 = boundingRect();//QPen pen(Qt::darkGreen);painter->setPen(QPen(Qt::darkGreen));}else{}
}
QPainterPath NodeUI::shape() const
{QRectF rect = boundingRect();QPainterPath path;path.addRoundRect(rect, 5,5);return path;
}void NodeUI::mousePressEvent(QGraphicsSceneMouseEvent *event)
{emit nodeIsPressed();qDebug()<<"pressed";QGraphicsItem::mousePressEvent(event);
}
void NodeUI::mouseReleaseEvent(QGraphicsSceneMouseEvent *event)
{update(boundingRect());QGraphicsItem::mouseReleaseEvent(event);
}
QString NodeUI::getMyText()
{return myText;
}
最后是scene与item的文件mainwindow.cpp，继承了QMainWindow，作用就是画一个应用程序框架
mainwindow.h
#ifndef MAINWINDOW_H
#define MAINWINDOW_H#include <QtGui/QMainWindow>
#include <QGraphicsView>
#include <QGraphicsScene>
#include <QPointF>
#include "nodeui.h"
#include "myscene.h"
#include <QMap>class MainWindow : public QMainWindow
{Q_OBJECTpublic:MainWindow(QWidget *parent = 0);~MainWindow();NodeUI *selectedNodeUI();bool isNodeUiClicked();void nodeUiSizeAdjust();//varprotected:private:void GetScreenInfo();QGraphicsView *view;//QGraphicsScene *scene;MyScene *scene;//instead of (NodeUI *nodeui;)&(QPointF nodeUiPos;)//眼下弃用，因为QMap的顺序无法人为设定，依照内部key自己主动升序//QMap<NodeUI*,QPointF>nodeUiMaps;//NodeUI *currentNodeUI;//nodeui pressed or releasedvolatile bool mPressed;QList<NodeUI*> nodeUiLists;QList<QPointF> nodeUiPosLists;QList<QPixmap> nodeUiPixmapLists;
/*struct {QList<NodeUI*> nodelists;QList<QPointF> poslists;}ss;*///弃用NodeUI *nodeui;QPointF nodeUiPos;//sceen size info;qint16 sceenSizeX;qint16 sceenSizeY;
private slots:void isMoving(QPointF &pos);void isPressed();void isReleased();void selectionChanged();signals:void nodeUiClicked(NodeUI* node);
};#endif // MAINWINDOW_H
#include "mainwindow.h"
#include <QDesktopWidget>
#include <QApplication>
#include <QPixmap>
#include <QGraphicsItem>
#include <QMouseEvent>
#include <QWidget>
#include <QGraphicsPixmapItem>
#include <QMessageBox>
#include <QDebug>const qreal MY_NODEUI_POS_Y = 200;
const qreal MY_NODEUI_DIS = 110;
const qreal MY_NODEUI_STA = 90;
const int MYNODEUI_SIZE = 100;
const int MYNODEUI_SIZE_M = 20;
const int SCREEN_SIZE = 800;
MainWindow::MainWindow(QWidget *parent): QMainWindow(parent)
{//初始化mPressed = false;//get windows sizeGetScreenInfo();view = new QGraphicsView;scene = new MyScene();scene->setSceneRect(0,0,800,480);//newQString file;QString text;QPointF pos;NodeUI* node;//HOME:1file = QString(":/images/home.png");text = QString("Home");pos = QPointF(MY_NODEUI_STA,MY_NODEUI_POS_Y);node = new NodeUI(file,text,MYNODEUI_SIZE);node->setPos(pos);nodeUiLists.append(node);nodeUiPosLists.append(pos);nodeUiPixmapLists.append(node->pixmap());/*here cannot delete node!!!!!!!!!!!!!!!delete node;*///VIDIO:2file = QString(":/images/securitycamera.png");text = QString("Vidio");pos = QPointF(MY_NODEUI_STA+MY_NODEUI_DIS*1,MY_NODEUI_POS_Y);node = new NodeUI(file,text,MYNODEUI_SIZE);node->setPos(pos);nodeUiLists.append(node);nodeUiPosLists.append(pos);nodeUiPixmapLists.append(node->pixmap());//APPLICATION:3file = QString(":/images/application.png");text = QString("Application");pos = QPointF(MY_NODEUI_STA+MY_NODEUI_DIS*2,MY_NODEUI_POS_Y);node = new NodeUI(file,text,MYNODEUI_SIZE);node->setPos(pos);nodeUiLists.append(node);nodeUiPosLists.append(pos);nodeUiPixmapLists.append(node->pixmap());//NETWORK:4file = QString(":/images/network-2.png");text = QString("Network");pos = QPointF(MY_NODEUI_STA+MY_NODEUI_DIS*3,MY_NODEUI_POS_Y);node = new NodeUI(file,text,MYNODEUI_SIZE);node->setPos(pos);nodeUiLists.append(node);nodeUiPosLists.append(pos);nodeUiPixmapLists.append(node->pixmap());//COMPUTER:5file = QString(":/images/smartphone.png");text = QString("Phone");pos = QPointF(MY_NODEUI_STA+MY_NODEUI_DIS*4,MY_NODEUI_POS_Y);node = new NodeUI(file,text,MYNODEUI_SIZE);node->setPos(pos);nodeUiLists.append(node);nodeUiPosLists.append(pos);nodeUiPixmapLists.append(node->pixmap());//CUSTOMIZE:5file = QString(":/images/customize.png");text = QString("Setting");pos = QPointF(MY_NODEUI_STA+MY_NODEUI_DIS*5,MY_NODEUI_POS_Y);node = new NodeUI(file,text,MYNODEUI_SIZE);node->setPos(pos);nodeUiLists.append(node);nodeUiPosLists.append(pos);nodeUiPixmapLists.append(node->pixmap());//又一次计算UiSizenodeUiSizeAdjust();int i = 0;foreach(NodeUI* node_temp,nodeUiLists){node_temp->setFlags(QGraphicsItem::ItemIsMovable | QGraphicsItem::ItemIsSelectable);qDebug()<<"name:"<<node_temp->getMyText()<<nodeUiPosLists.at(i);scene->addItem(node_temp);i++;}//用于button的单机view->setScene(scene);//set drag mode//view->setDragMode(QGraphicsView::RubberBandDrag);view->setRenderHints(QPainter::Antialiasing);//no menuview->setContextMenuPolicy(Qt::NoContextMenu);view->setBackgroundBrush(QImage(":/images/shuibo2.jpg"));//view->setViewportUpdateMode(QGraphicsView::BoundingRectViewportUpdate);//view->setCacheMode(QGraphicsView::CacheBackground);setCentralWidget(view);setWindowTitle(tr("Main Window"));
}
//槽，当scene鼠标拖拽是运行
//控制UI图标的水平
void MainWindow::isMoving(QPointF &pos)
{int i=0;if(mPressed){foreach(NodeUI* node,nodeUiLists){node->setPos(nodeUiPosLists.at(i).x()+pos.x(),MY_NODEUI_POS_Y);i++;}nodeUiSizeAdjust();}
}
//槽，当nodeui鼠标按下时运行,调用selectedNodeUI函数，更新currentNodeUI变量
//除此之外，selectionChanged()也是一个槽，由scene调用
void MainWindow::isPressed()
{selectionChanged();mPressed = true;
}
//槽，当nodeui鼠标释放时运行
//应当设置标志位，让UI图片停止对鼠标拖动事件的响应
void MainWindow::isReleased()
{mPressed = false;if(isNodeUiClicked())qDebug()<<"clicked";qDebug()<<"release";
}//槽，当scene的selectedItem变化时，发送同名信号到此槽
void MainWindow::selectionChanged()
{int i=0,j=0;QList<QGraphicsItem *> items = scene->selectedItems();if (items.count() == 1) {//当前所选择的UI图标的坐标QPointF pos = items.first()->pos();NodeUI* node_temp = dynamic_cast<NodeUI *>(items.first());qDebug()<<"items.x:"<<pos.x()<<"items.y:"<<pos.y();foreach(NodeUI* node,nodeUiLists){if(node == node_temp)break;i++;}j=i;i=0;foreach(QPointF ppos,nodeUiPosLists){nodeUiPosLists[i].setX((i-j)*MY_NODEUI_DIS+pos.x());nodeUiPosLists[i].setY(MY_NODEUI_POS_Y);i++;}} else {return;}
}
//推断是否Nodeui接收的是否是单击信号。
//推断根据是当前单击的nodeui对象的pos与存储在nodeUiPosListsd的位置比較，相等则为单击
bool MainWindow::isNodeUiClicked()
{int i=-1;QList<QGraphicsItem *> items = scene->selectedItems();if (items.count() == 1) {QPointF pos = items.first()->pos();NodeUI* node_temp = dynamic_cast<NodeUI *>(items.first());if(pos ==nodeUiPosLists.at(i)){//emit nodeUiClicked(node_temp);QMessageBox::information(this,"New Window","will open : "+node_temp->getMyText());return true;}}return false;
}
void MainWindow::nodeUiSizeAdjust()
{quint16 i=0;foreach(NodeUI* node,nodeUiLists){//qDebug()<<"i= "<<i;QPointF pos=node->pos();pos.setX(node->pos().x()+MYNODEUI_SIZE/2);//pos.setX(node->pos().x()+node->pixmap().width());if(pos.x()>=0 && pos.x()<=SCREEN_SIZE/2){//(MYNODEUI_SIZE-MYNODEUI_SIZE_M)/(SCREEN_SIZE/2)==(size-20)/pos.x()quint16 size=pos.x()/5+20;QPixmap pixmap = nodeUiPixmapLists.at(i);//QPixmap pixmap = nodeUiLists.at(i)->pixmap();pixmap = pixmap.scaled(size,size,Qt::IgnoreAspectRatio, Qt::SmoothTransformation);nodeUiLists[i]->setPixmap(pixmap);}//if(pos.x()>SCREEN_SIZE/2 && pos.x()<=SCREEN_SIZE)if(pos.x()>SCREEN_SIZE/2 && pos.x()<=SCREEN_SIZE+10){//(MYNODEUI_SIZE-MYNODEUI_SIZE_M)/(SCREEN_SIZE/2)==(size-20)/pos.x()quint16 size=(SCREEN_SIZE-pos.x())/5+20;QPixmap pixmap = nodeUiPixmapLists.at(i);//QPixmap pixmap = nodeUiLists.at(i)->pixmap();pixmap = pixmap.scaled(size,size,Qt::IgnoreAspectRatio, Qt::SmoothTransformation);nodeUiLists[i]->setPixmap(pixmap);}i++;}
}
MainWindow::~MainWindow()
{
}
//获取设备分辨率的呢个信息
void MainWindow::GetScreenInfo()
{QDesktopWidget* desktopWidget = QApplication::desktop();//获取可用桌面大小//QRect deskRect = desktopWidget->availableGeometry();//获取设备屏幕大小QRect screenRect = desktopWidget->screenGeometry();sceenSizeX = screenRect.width();sceenSizeY = screenRect.height();//获取系统设置的屏幕个数（屏幕拷贝方式该值为1）//g_nScreenCount = desktopWidget->screenCount();
}实例化MainWindow
#include <QtGui/QApplication>
#include "mainwindow.h"int main(int argc, char *argv[])
{QApplication a(argc, argv);MainWindow w;w.setWindowOpacity(1);w.setWindowFlags(Qt::FramelessWindowHint);w.setAttribute(Qt::WA_TranslucentBackground);w.show();//w.showFullScreen();return a.exec();
}
大概都写了注解了，事实上看看一个名称也该大概了解其作用，写这程序时遇到的问题都记录在了前一篇qt学习笔记（四）中，记录一下，以备不时之需