C++ 图形场景中的QMouseEvents不工作

我对Qt相当陌生，我创建了一个简单的应用程序，在一个自定义QGraphicscene中初始化了许多自定义QGraphicsSite。每个项目都使用随机起始位置和权重值初始化，权重值取决于项目的位置。在鼠标移动事件中，我希望根据鼠标光标的位置更新项目的权重值

我认为我的mouseMoveEvent在Graphicscene中无法识别，它似乎在主窗口中工作正常，我在状态栏中实现了一个标签，以显示mouseMoveEvent的数量和mouseMoveEvent的X-Y位置

代码如下：

自定义图形场景。h:

class ParticleScene : public QGraphicsScene
{
public:
    ParticleScene();

protected: 
    void mouseMoveEvent(QGraphicsSceneMouseEvent *event);

private:
    qreal WTotal;
    Particle *particle;

} 

ParticleScene::ParticleScene()
{

//this->setBackgroundBrush(Qt::gray);
this->setSceneRect(0,0,500,500);

WTotal=0;
int ParticleCount =5;
for (int i =0; i<ParticleCount; i++)
    {
    particle= new Particle();
    particle->StartX= rand()%500;
    particle->StartY= rand()%500;
    particle->W= qSqrt(qPow(particle->StartX,2) + qPow(particle->StartY,2));
    particle->setPos(particle->StartX,particle->StartY);
    this->addItem(particle);
    particle->setFocus();
    WTotal+=particle->W;
    }

}

void ParticleScene::mouseMoveEvent(QGraphicsSceneMouseEvent *event)
{
    update();
    QGraphicsScene::mouseMoveEvent(event);
}

Particle::Particle()
{
//    setFlag(ItemIsMovable);
    setFlag(ItemIsFocusable);
}

QRectF Particle::boundingRect() const
{
     return QRect(0,0,120,30);
}

void Particle::paint(QPainter *painter, const QStyleOptionGraphicsItem *option, QWidget *widget)
{
    QRectF rec= boundingRect();
    QBrush Brush(Qt::white);

    painter->fillRect(rec,Brush);
    painter->drawText(15,15,"Weight: "+QString::number(W));
    painter->drawRect(rec);

}

void Particle::keyPressEvent(QKeyEvent *event)
{

    switch(event->key()){
    case Qt::Key_Right:{
        moveBy(30,0);
        break;}
    case Qt::Key_Left:{
        moveBy(-30,0);
        break;}
    case Qt::Key_Up:{
        moveBy(0,-30);
        break;}
    case Qt::Key_Down:{
        moveBy(0,30);
        break;}
    }
    update();
}

void Particle::mouseMoveEvent(QGraphicsSceneMouseEvent *event)
{
    this->W= this->W / qSqrt(qPow(event->pos().x(),2) + qPow(event->pos().y(),2));
    moveBy(30,0);
    update();
}

自定义图形场景。cpp:

class ParticleScene : public QGraphicsScene
{
public:
    ParticleScene();

protected: 
    void mouseMoveEvent(QGraphicsSceneMouseEvent *event);

private:
    qreal WTotal;
    Particle *particle;

} 

ParticleScene::ParticleScene()
{

//this->setBackgroundBrush(Qt::gray);
this->setSceneRect(0,0,500,500);

WTotal=0;
int ParticleCount =5;
for (int i =0; i<ParticleCount; i++)
    {
    particle= new Particle();
    particle->StartX= rand()%500;
    particle->StartY= rand()%500;
    particle->W= qSqrt(qPow(particle->StartX,2) + qPow(particle->StartY,2));
    particle->setPos(particle->StartX,particle->StartY);
    this->addItem(particle);
    particle->setFocus();
    WTotal+=particle->W;
    }

}

void ParticleScene::mouseMoveEvent(QGraphicsSceneMouseEvent *event)
{
    update();
    QGraphicsScene::mouseMoveEvent(event);
}

Particle::Particle()
{
//    setFlag(ItemIsMovable);
    setFlag(ItemIsFocusable);
}

QRectF Particle::boundingRect() const
{
     return QRect(0,0,120,30);
}

void Particle::paint(QPainter *painter, const QStyleOptionGraphicsItem *option, QWidget *widget)
{
    QRectF rec= boundingRect();
    QBrush Brush(Qt::white);

    painter->fillRect(rec,Brush);
    painter->drawText(15,15,"Weight: "+QString::number(W));
    painter->drawRect(rec);

}

void Particle::keyPressEvent(QKeyEvent *event)
{

    switch(event->key()){
    case Qt::Key_Right:{
        moveBy(30,0);
        break;}
    case Qt::Key_Left:{
        moveBy(-30,0);
        break;}
    case Qt::Key_Up:{
        moveBy(0,-30);
        break;}
    case Qt::Key_Down:{
        moveBy(0,30);
        break;}
    }
    update();
}

void Particle::mouseMoveEvent(QGraphicsSceneMouseEvent *event)
{
    this->W= this->W / qSqrt(qPow(event->pos().x(),2) + qPow(event->pos().y(),2));
    moveBy(30,0);
    update();
}

Particle.cpp:

class ParticleScene : public QGraphicsScene
{
public:
    ParticleScene();

protected: 
    void mouseMoveEvent(QGraphicsSceneMouseEvent *event);

private:
    qreal WTotal;
    Particle *particle;

} 

ParticleScene::ParticleScene()
{

//this->setBackgroundBrush(Qt::gray);
this->setSceneRect(0,0,500,500);

WTotal=0;
int ParticleCount =5;
for (int i =0; i<ParticleCount; i++)
    {
    particle= new Particle();
    particle->StartX= rand()%500;
    particle->StartY= rand()%500;
    particle->W= qSqrt(qPow(particle->StartX,2) + qPow(particle->StartY,2));
    particle->setPos(particle->StartX,particle->StartY);
    this->addItem(particle);
    particle->setFocus();
    WTotal+=particle->W;
    }

}

void ParticleScene::mouseMoveEvent(QGraphicsSceneMouseEvent *event)
{
    update();
    QGraphicsScene::mouseMoveEvent(event);
}

Particle::Particle()
{
//    setFlag(ItemIsMovable);
    setFlag(ItemIsFocusable);
}

QRectF Particle::boundingRect() const
{
     return QRect(0,0,120,30);
}

void Particle::paint(QPainter *painter, const QStyleOptionGraphicsItem *option, QWidget *widget)
{
    QRectF rec= boundingRect();
    QBrush Brush(Qt::white);

    painter->fillRect(rec,Brush);
    painter->drawText(15,15,"Weight: "+QString::number(W));
    painter->drawRect(rec);

}

void Particle::keyPressEvent(QKeyEvent *event)
{

    switch(event->key()){
    case Qt::Key_Right:{
        moveBy(30,0);
        break;}
    case Qt::Key_Left:{
        moveBy(-30,0);
        break;}
    case Qt::Key_Up:{
        moveBy(0,-30);
        break;}
    case Qt::Key_Down:{
        moveBy(0,30);
        break;}
    }
    update();
}

void Particle::mouseMoveEvent(QGraphicsSceneMouseEvent *event)
{
    this->W= this->W / qSqrt(qPow(event->pos().x(),2) + qPow(event->pos().y(),2));
    moveBy(30,0);
    update();
}

MainWindow.h和cpp:此处的状态栏标签正确显示鼠标坐标，即此处的mouseMoveEvent函数

namespace Ui {
class MainWindow;
}

class MainWindow : public QMainWindow
{
   Q_OBJECT

public:
    explicit MainWindow(QWidget *parent = 0);
    ~MainWindow();

    void mouseMoveEvent(QMouseEvent *event);
protected:

private:
    Ui::MainWindow *ui;
    ParticleScene *scene;
    QLabel *statlabel;

    int moves;
};

MainWindow::MainWindow(QWidget *parent) :
QMainWindow(parent),
ui(new Ui::MainWindow)
{
    ui->setupUi(this);  

    statlabel=new QLabel(this);
    ui->statusBar->addWidget(statlabel);
    statlabel->setText ("Mouse Coordinates");

    setCentralWidget(ui->graphicsView);
    centralWidget()->setAttribute(Qt::WA_TransparentForMouseEvents);
    ui->graphicsView->setMouseTracking(true);

    scene= new ParticleScene();
    ui->graphicsView->setScene(scene);
    ui->graphicsView->setRenderHint(QPainter::Antialiasing);

    moves=0;

}

MainWindow::~MainWindow()
{
   delete ui;
}

void MainWindow::mouseMoveEvent(QMouseEvent *event)
{
    moves+=1;
    statlabel->setText("MouseMoves " +QString::number(moves)+ " X:"+QString::number(event->pos().x())+"-- Y:"+QString::number(event->pos().y()));
}

我在程序中遗漏了什么导致mousemoveevent无法运行，有没有办法将所有项目集中在一起？我是否需要将它们制作成QList

---

在程序的下一步中，我希望项目根据其所有权重的总和更新其权重值，并根据使用新权重值确定新位置的算法移动

您缺少某种容器，您可以在其中保存所有粒子。在当前实现中，ParticleScene将粒子指针作为私有变量。您正在循环中创建多个粒子（它们是QGraphicsItem的），但只有最后一个指针存储在自定义场景中。正如您所说，您可以使用QList来保存粒子

我还假设您希望在场景中移动项目。为此，您还可以为MousePress事件（捕捉项目被按下的时间和坐标）、MouseMove（用于实际移动项目）和mouseRelease（例如，用于计算权重或发送将触发所有项目权重计算的信号）创建自己的实现

与其将所有项目保留在自定义场景中，不如创建一个新类，例如，ItemsManager，在其中存储所有项目，并创建指向场景的指针。在该类中，您可以执行与项目权重计算有关的所有操作或其他所需操作。

删除函数ParticleScene:：mouseMoveEvent。您不需要在此处调用update，除非该函数中有其他代码，否则它不会为您做任何事情。当您在场景中移动项目时，只要其边界矩形正确，它将为您进行更新。您可以一次选择多个项目，尽管a可能是您要查找的项目。