本文共 2743 字，大约阅读时间需要 9 分钟。

相当于N 张图片叠加起来使用，先绘制其他图片，因为只有有效区域的Alpha值为0xff，其他为0x00，这样就不会显示出来，同时不会响应鼠标事件。

必须要先绘制子items,再绘制背景，防止背景将items盖住。

如果items和background items的尺寸一致的话，可以适应窗体的缩放。

#ifndef ZGRAPHICSITEM_H

#define ZGRAPHICSITEM_H #include <QObject> #include <QGraphicsPixmapItem> #include <QGraphicsSceneMouseEvent> class ZGraphicsItem : public QObject,public QGraphicsPixmapItem {     Q_OBJECT public:     explicit ZGraphicsItem(QGraphicsItem *parent = 0); protected:     void mousePressEvent(QGraphicsSceneMouseEvent *event); signals:     void ZSignalClicked(); public slots: }; #endif // ZGRAPHICSITEM_H #include "zgraphicsitem.h" #include <QCursor> ZGraphicsItem::ZGraphicsItem(QGraphicsItem *parent) :     QGraphicsPixmapItem(parent) { } void ZGraphicsItem::mousePressEvent(QGraphicsSceneMouseEvent *event) {     if(event->button()==Qt::LeftButton)     {         emit this->ZSignalClicked();     }     QGraphicsPixmapItem::mousePressEvent(event); }

#ifndef ZWIDGET_H

#define ZWIDGET_H #include <QWidget> #include <QGraphicsScene> #include <QGraphicsView> #include <QGraphicsItem> #include <QHBoxLayout> #include <zgraphicsitem.h> class ZWidget : public QWidget {     Q_OBJECT public:     ZWidget(QWidget *parent = 0);     ~ZWidget(); private slots:     void ZSlotLeftTopClicked(); private:     QGraphicsScene *m_Scene;     QGraphicsView *m_view;     QVBoxLayout *m_vlayoutMain;     //background item.     ZGraphicsItem *m_BackItem;     ZGraphicsItem *m_LeftTopItem;     ZGraphicsItem *m_ZiMuCeShiItem; }; #endif // ZWIDGET_H #include "zwidget.h" #include <QDebug> ZWidget::ZWidget(QWidget *parent)     : QWidget(parent) {     this->m_Scene=new QGraphicsScene;     this->m_view=new QGraphicsView(this->m_Scene);     //here we must create action-sensitive item first,     //at the last draw the background to avoid hide others items.     this->m_LeftTopItem=new ZGraphicsItem;     this->m_LeftTopItem->setPixmap(QPixmap(":/images/zuoshangjiao.png"));     connect(this->m_LeftTopItem,SIGNAL(ZSignalClicked()),this,SLOT(ZSlotLeftTopClicked()));     this->m_Scene->addItem(this->m_LeftTopItem);     this->m_ZiMuCeShiItem=new ZGraphicsItem;     this->m_ZiMuCeShiItem->setPixmap(QPixmap(":/images/zimuceshi.png"));     connect(this->m_ZiMuCeShiItem,SIGNAL(ZSignalClicked()),this,SLOT(ZSlotLeftTopClicked()));     this->m_Scene->addItem(this->m_ZiMuCeShiItem);     //create items.     this->m_BackItem=new ZGraphicsItem;     this->m_BackItem->setPixmap(QPixmap(":/images/background.png"));     this->m_Scene->addItem(this->m_BackItem);     //layout main.     this->m_vlayoutMain=new QVBoxLayout;     this->m_vlayoutMain->addWidget(this->m_view);     this->setLayout(this->m_vlayoutMain); } ZWidget::~ZWidget() {     delete this->m_view;     delete this->m_BackItem;     delete this->m_LeftTopItem;     delete this->m_ZiMuCeShiItem;     delete this->m_Scene;     delete this->m_vlayoutMain; } void ZWidget::ZSlotLeftTopClicked() {     static int i=0;     qDebug()<<"clicked:"<<i++; }