C++ 组合QGraphicsItem未检测到子项上的单击

我正在尝试对

qgraphicsrecitem

进行一个简单的扩展，它允许我调整矩形的大小并用鼠标移动它。我在要启用拖动功能的拐角处用椭圆拱对控制柄进行建模，实现为

QGraphicsEllipseItem

s:

class QGraphicsBoxWithHandlesItem : public QObject, public QGraphicsRectItem
{
    Q_OBJECT

    typedef enum {
        None,
        BottomLeft,
        TopRight
    } ActiveAnchor;

private:
    QGraphicsEllipseItem m_anchorBottomLeft;
    QGraphicsEllipseItem m_anchorTopRight;
    float m_anchorRadius;
    ActiveAnchor m_activeAnchor;

public:
    QGraphicsBoxWithHandlesItem(QRectF r, float handlesRadius = 20.0, QGraphicsItem *parent = nullptr);

    void setAnchorRadius(float radius);
    float getAnchorRadius();

    QPainterPath shape() const;

protected:
    void mousePressEvent(QGraphicsSceneMouseEvent * event);
    void mouseMoveEvent(QGraphicsSceneMouseEvent * event);
    void mouseReleaseEvent(QGraphicsSceneMouseEvent * event);
};

我希望能够检测矩形和句柄项上的点击（这是必要的，因为如果矩形太小，句柄是唯一容易点击的区域），因此我想扩展

QGraphicsRectItem:：shape（）

，将子项的路径添加到返回的

QPainterPath

中（调整坐标以使其相对于父项）：

然而，我得到的是，现在手柄区域内的点击被完全忽略，只处理矩形中心区域的点击

当项目具有非平凡形状时，扩展其可点击区域的正确方法是什么

更新：我试图在句柄上设置

ItemIsSelectable

标志，现在，如果我单击它，我看到它被选中。但是，我仍然没有在父级中获得任何

mousePressEvent

。我做错了什么

编辑： 这是构造函数实现：

QGraphicsBoxWithHandlesItem::QGraphicsBoxWithHandlesItem( QRectF r, float handlesRadius, QGraphicsItem * parent) :
    QGraphicsRectItem(parent),
    m_anchorRadius(handlesRadius),
    m_activeAnchor(None)
{
    setFlag(QGraphicsItem::ItemIsMovable);
    setFlag(QGraphicsItem::ItemIsSelectable);

    setRect(r);

    m_anchorBottomLeft.setRect(-m_anchorRadius, -m_anchorRadius, m_anchorRadius*2, m_anchorRadius*2);
    m_anchorBottomLeft.setPos(rect().bottomLeft());
    m_anchorBottomLeft.setSpanAngle(90 * 16); // angle is in 16ths of degree
    m_anchorBottomLeft.setParentItem(this);

    m_anchorTopRight.setRect(-m_anchorRadius, -m_anchorRadius, m_anchorRadius*2, m_anchorRadius*2);
    m_anchorTopRight.setPos(rect().topRight());
    m_anchorTopRight.setStartAngle(180 * 16); // angle is in 16ths of degree
    m_anchorTopRight.setSpanAngle(90 * 16); // angle is in 16ths of degree
    m_anchorTopRight.setParentItem(this);
}

---

您的QGraphicsSellipseitem位于基本项之上，因此鼠标事件永远不会出现在您的面前

您需要做的是使用sceneEventFilter，但由于QGraphicsSellipseitem是主项的子项，它们永远不会移动，因此它们不应该有父项，但您应该将它们直接添加到场景中

完整功能在以下代码中实现：

*.h

#ifndef QGRAPHICSBOXWITHHANDLESITEM_H
#define QGRAPHICSBOXWITHHANDLESITEM_H

#include <QGraphicsRectItem>
#include <QObject>

class QGraphicsBoxWithHandlesItem : public QObject, public QGraphicsRectItem
{
    Q_OBJECT
    enum ActiveAnchor{
        None,
        BottomLeft,
        TopRight
    };

public:
    QGraphicsBoxWithHandlesItem(QRectF r, float handlesRadius = 20.0, QGraphicsItem *parent = nullptr);
protected:
    QVariant itemChange(GraphicsItemChange change, const QVariant &value);
    bool sceneEventFilter(QGraphicsItem *watched, QEvent *event);
private:
    QGraphicsEllipseItem m_anchorBottomLeft;
    QGraphicsEllipseItem m_anchorTopRight;
    float m_anchorRadius;
    ActiveAnchor m_activeAnchor;
};

#endif // QGRAPHICSBOXWITHHANDLESITEM_H

#如果使用无手柄的QGraphicsBox项目
#定义QGRAPHICSBOXWITHHANDLESITEM_H
#包括
#包括
类QGraphicsBoxWithHandlesItem:公共QObject，公共QGraphicsRecItem
{
Q_对象
枚举活动锚{
没有一个
左下角，
右上角
};
公众：
QGraphicsBoxWithHandlesItem（QRectF r，float handlesRadius=20.0，QGraphicsSitem*父项=nullptr）；
受保护的：
QVariant项目变更（图形站点变更、常量QVariant和值）；
bool sceneEventFilter（QGraphicsItem*监视，QEvent*事件）；
私人：
QGraphicsSellipseitem m_anchorBottomLeft；
QGraphics Sellipseitem m_anchorTopRight；
浮动m_anchorRadius；
主动锚m_主动锚；
};
#endif//qgraphicsboxwithhandles项目

*.cpp

#include "qgraphicsboxwithhandlesitem.h"

#include <QEvent>
#include <QGraphicsScene>
#include <QDebug>

QGraphicsBoxWithHandlesItem::QGraphicsBoxWithHandlesItem( QRectF r, float handlesRadius, QGraphicsItem * parent) :
    QGraphicsRectItem(parent),
    m_anchorRadius(handlesRadius),
    m_activeAnchor(None)
{
    setFlag(QGraphicsItem::ItemIsMovable);
    setFlag(QGraphicsItem::ItemIsSelectable);
    setFlag(QGraphicsItem::ItemSendsGeometryChanges);

    setRect(r);

    m_anchorBottomLeft.setRect(-m_anchorRadius, -m_anchorRadius, m_anchorRadius*2, m_anchorRadius*2);
    m_anchorBottomLeft.setPos(rect().bottomLeft());
    m_anchorBottomLeft.setSpanAngle(90 * 16); // angle is in 16ths of degree
    //m_anchorBottomLeft.setParentItem(this);
    m_anchorBottomLeft.setFlag(QGraphicsItem::ItemIsMovable);
    m_anchorBottomLeft.setFlag(QGraphicsItem::ItemIsSelectable);

    m_anchorTopRight.setRect(-m_anchorRadius, -m_anchorRadius, m_anchorRadius*2, m_anchorRadius*2);
    m_anchorTopRight.setPos(rect().topRight());
    m_anchorTopRight.setStartAngle(180 * 16); // angle is in 16ths of degree
    m_anchorTopRight.setSpanAngle(90 * 16); // angle is in 16ths of degree
    //m_anchorTopRight.setParentItem(this);
    m_anchorTopRight.setFlag(QGraphicsItem::ItemIsMovable);
    m_anchorTopRight.setFlag(QGraphicsItem::ItemIsSelectable);
}

QVariant QGraphicsBoxWithHandlesItem::itemChange(GraphicsItemChange change, const QVariant & value){
    if(change == QGraphicsItem::ItemSceneHasChanged){
        if(scene()){
            scene()->addItem(&m_anchorBottomLeft);
            scene()->addItem(&m_anchorTopRight);
            m_anchorBottomLeft.installSceneEventFilter(this);
            m_anchorTopRight.installSceneEventFilter(this);
        }
    }
    else if (change == QGraphicsItem::ItemPositionHasChanged) {
        m_anchorBottomLeft.setPos(mapToScene(rect().bottomLeft()));
        m_anchorTopRight.setPos(mapToScene(rect().topRight()));
    }
    return QGraphicsRectItem::itemChange(change, value);
}

bool QGraphicsBoxWithHandlesItem::sceneEventFilter(QGraphicsItem *watched, QEvent *event)
{
    if(watched == &m_anchorTopRight){
        switch (event->type()) {
        case QEvent::GraphicsSceneMousePress:{
            //mousePressEvent
            qDebug()<<"mousePressEvent m_anchorTopRight";
            break;
        }
        case QEvent::GraphicsSceneMouseMove:{
            // mouseMoveEvent
            QRectF r = rect();
            auto p = m_anchorTopRight.mapToScene(m_anchorTopRight.rect().center());
            r.setTopRight(mapFromScene(p));
            setRect(r);
            qDebug()<<"mouseMoveEvent m_anchorTopRight";
            break;
        }
        case QEvent::GraphicsSceneMouseRelease :{
            //mouseReleaseEvent
            qDebug()<<"mouseReleaseEvent m_anchorTopRight";
            break;
        }
        }
    }

    if(watched == &m_anchorBottomLeft){
        switch (event->type()) {
        case QEvent::GraphicsSceneMousePress:{
            //mousePressEvent
            qDebug()<<"mousePressEvent m_anchorBottomLeft";
            break;
        }
        case QEvent::GraphicsSceneMouseMove:{
            // mouseMoveEvent
            QRectF r = rect();
            auto p = m_anchorBottomLeft.mapToScene(m_anchorBottomLeft.rect().center());
            r.setBottomLeft(mapFromScene(p));
            setRect(r);
            qDebug()<<"mouseMoveEvent m_anchorBottomLeft";
            break;
        }
        case QEvent::GraphicsSceneMouseRelease :{
            //mouseReleaseEvent
            qDebug()<<"mouseReleaseEvent m_anchorBottomLeft";
            break;
        }
        }
    }
    return  QGraphicsRectItem::sceneEventFilter(watched, event);
}

#包括“qgraphicsboxwithhandlesitem.h”
#包括
#包括
#包括
QGraphicsBoxWithHandlesItem:：QGraphicsBoxWithHandlesItem（QRectF r、浮点handlesRadius、QGraphicsSiteM*父项）：
QGraphicsRectItem（父级），
m_anchorRadius（handlesRadius），
m_activeAnchor（无）
{
setFlag（QGraphicsItem:：ItemIsMovable）；
setFlag（QGraphicsItem:：ItemIsSelectable）；
setFlag（QGraphicsItem:：ItemSendsGeometryChanges）；
setRect（r）；
m_anchorBottomLeft.setRect（-m_anchorRadius，-m_anchorRadius，m_anchorRadius*2，m_anchorRadius*2）；
m_anchorBottomLeft.setPos（rect（）.bottomLeft（））；
m_anchorBottomLeft.设置角度（90*16）；//角度为16度
//m_anchorBottomLeft.setParentItem（此项）；
setFlag（QGraphicsItem:：ItemIsMovable）；
m_anchorBottomLeft.setFlag（QGraphicsItem:：itemisselect）；
m_anchorTopRight.setRect（-m_anchorRadius，-m_anchorRadius，m_anchorRadius*2，m_anchorRadius*2）；
m_anchotopright.setPos（rect（）.topRight（））；
m_anchorTopRight.设置起始角度（180*16）；//角度为16度
m_anchorTopRight.设置角度（90*16）；//角度为16度
//m_AnchortoRight.setParentItem（此项）；
m_anchorTopRight.setFlag（QGraphicsItem:：ItemIsMovable）；
m_anchorTopRight.setFlag（QGraphicsItem:：itemisselect）；
}
QVariant QGraphicsBoxWithHandlesItem:：itemChange（GraphicsSitemChange更改，常量QVariant和值）{
if（change==QGraphicsItem:：ItemSceneHasChanged）{
如果（场景（））{
场景（）->附加项（&m_anchorBottomLeft）；
场景（）->附加项（&m_AnchortoRight）；
m_anchorBottomLeft.installSceneEventFilter（此）；
m_anchorTopRight.installSceneEventFilter（此）；
}
}
else if（change==QGraphicsItem:：ItemPositionHasChanged）{
m_anchorBottomLeft.setPos（映射到场景（rect（）.bottomLeft（））；
m_anchotopright.setPos（映射到场景（rect（）.topRight（））；
}
返回qgraphicsrecitem:：itemChange（change，value）；
}
bool QGraphicsBoxWithHandlesItem:：sceneEventFilter（QGraphicsSitem*监视，QEvent*事件）
{
如果（观看==&m_AnchortoRight）{
开关（事件->类型（）{
案例QEvent:：GraphicsCenemousePress:{
//鼠标垫
qDebug（）你是如何将m_anchorBottomLeft和m_AnchorToRight添加到场景中的？好问题。我不确定。它们是root
Rect
项的子项，我将其添加到场景中。我假设这些子项是与父项一起添加的，但我不确定情况是否如此。当我们需要解决此问题时，我们使用@ypnos谢谢，我会定义我真的想看看它！（我希望我昨天找到了它。）我仍然想知道我的代码中发生了什么，但是，如果只是想知道在我再次需要它时如何做：）谢谢，我试过了代码，它似乎起了作用（我仍然需要用我在原始代码中的一些东西来修改它，但这确实满足了我的需要）。
#include "qgraphicsboxwithhandlesitem.h"

#include <QEvent>
#include <QGraphicsScene>
#include <QDebug>

QGraphicsBoxWithHandlesItem::QGraphicsBoxWithHandlesItem( QRectF r, float handlesRadius, QGraphicsItem * parent) :
    QGraphicsRectItem(parent),
    m_anchorRadius(handlesRadius),
    m_activeAnchor(None)
{
    setFlag(QGraphicsItem::ItemIsMovable);
    setFlag(QGraphicsItem::ItemIsSelectable);
    setFlag(QGraphicsItem::ItemSendsGeometryChanges);

    setRect(r);

    m_anchorBottomLeft.setRect(-m_anchorRadius, -m_anchorRadius, m_anchorRadius*2, m_anchorRadius*2);
    m_anchorBottomLeft.setPos(rect().bottomLeft());
    m_anchorBottomLeft.setSpanAngle(90 * 16); // angle is in 16ths of degree
    //m_anchorBottomLeft.setParentItem(this);
    m_anchorBottomLeft.setFlag(QGraphicsItem::ItemIsMovable);
    m_anchorBottomLeft.setFlag(QGraphicsItem::ItemIsSelectable);

    m_anchorTopRight.setRect(-m_anchorRadius, -m_anchorRadius, m_anchorRadius*2, m_anchorRadius*2);
    m_anchorTopRight.setPos(rect().topRight());
    m_anchorTopRight.setStartAngle(180 * 16); // angle is in 16ths of degree
    m_anchorTopRight.setSpanAngle(90 * 16); // angle is in 16ths of degree
    //m_anchorTopRight.setParentItem(this);
    m_anchorTopRight.setFlag(QGraphicsItem::ItemIsMovable);
    m_anchorTopRight.setFlag(QGraphicsItem::ItemIsSelectable);
}

QVariant QGraphicsBoxWithHandlesItem::itemChange(GraphicsItemChange change, const QVariant & value){
    if(change == QGraphicsItem::ItemSceneHasChanged){
        if(scene()){
            scene()->addItem(&m_anchorBottomLeft);
            scene()->addItem(&m_anchorTopRight);
            m_anchorBottomLeft.installSceneEventFilter(this);
            m_anchorTopRight.installSceneEventFilter(this);
        }
    }
    else if (change == QGraphicsItem::ItemPositionHasChanged) {
        m_anchorBottomLeft.setPos(mapToScene(rect().bottomLeft()));
        m_anchorTopRight.setPos(mapToScene(rect().topRight()));
    }
    return QGraphicsRectItem::itemChange(change, value);
}

bool QGraphicsBoxWithHandlesItem::sceneEventFilter(QGraphicsItem *watched, QEvent *event)
{
    if(watched == &m_anchorTopRight){
        switch (event->type()) {
        case QEvent::GraphicsSceneMousePress:{
            //mousePressEvent
            qDebug()<<"mousePressEvent m_anchorTopRight";
            break;
        }
        case QEvent::GraphicsSceneMouseMove:{
            // mouseMoveEvent
            QRectF r = rect();
            auto p = m_anchorTopRight.mapToScene(m_anchorTopRight.rect().center());
            r.setTopRight(mapFromScene(p));
            setRect(r);
            qDebug()<<"mouseMoveEvent m_anchorTopRight";
            break;
        }
        case QEvent::GraphicsSceneMouseRelease :{
            //mouseReleaseEvent
            qDebug()<<"mouseReleaseEvent m_anchorTopRight";
            break;
        }
        }
    }

    if(watched == &m_anchorBottomLeft){
        switch (event->type()) {
        case QEvent::GraphicsSceneMousePress:{
            //mousePressEvent
            qDebug()<<"mousePressEvent m_anchorBottomLeft";
            break;
        }
        case QEvent::GraphicsSceneMouseMove:{
            // mouseMoveEvent
            QRectF r = rect();
            auto p = m_anchorBottomLeft.mapToScene(m_anchorBottomLeft.rect().center());
            r.setBottomLeft(mapFromScene(p));
            setRect(r);
            qDebug()<<"mouseMoveEvent m_anchorBottomLeft";
            break;
        }
        case QEvent::GraphicsSceneMouseRelease :{
            //mouseReleaseEvent
            qDebug()<<"mouseReleaseEvent m_anchorBottomLeft";
            break;
        }
        }
    }
    return  QGraphicsRectItem::sceneEventFilter(watched, event);
}