c – 在Qt中右键单击事件以打开上下文菜单

我有一段代码调用一个mousePressEvent.我有左键输出光标的坐标,我右键单击相同,但是我也想要右键单击打开一个上下文菜单.我到目前为止的代码是：

void plotspace::mousePressEvent(QMouseEvent*event)
{
    double trange = _timeonright - _timeonleft;
    int twidth = width();
    double tinterval = trange/twidth;
 
    int xclicked = event->x();
 
    _xvaluecoordinate = _timeonleft+tinterval*xclicked;
 
 
 
    double fmax = Data.plane(X,0).max();
    double fmin = Data.plane(X,0).min();
    double fmargin = (fmax-fmin)/40;
    int fheight = height();
    double finterval = ((fmax-fmin)+4*fmargin)/fheight;
 
    int yclicked = event->y();
 
    _yvaluecoordinate = (fmax+fmargin)-finterval*yclicked;
 
    cout<<"Time(s): "<<_xvaluecoordinate<<endl;
    cout<<"Flux: "<<_yvaluecoordinate<<endl;
    cout << "timeonleft= " << _timeonleft << "\n";
 
    returncoordinates();
 
    emit updateCoordinates();
 
    if (event->button()==Qt::RightButton)
    {
            contextmenu->setContextMenuPolicy(Qt::CustomContextMenu);
 
            connect(contextmenu,SIGNAL(customContextMenuRequested(const QPoint&)),this,SLOT(ShowContextMenu(const QPoint&)));
 
            void A::ShowContextMenu(const QPoint &pos) 
            {
                QMenu *menu = new QMenu;
                menu->addAction(tr("Remove Data Point"),SLOT(test_slot()));
 
                menu->exec(w->mapToGlobal(pos));
            }
 
    }   
 
}

我知道我的问题本质上是非常根本的,而且“上下文菜单”没有被正确的声明.我从许多来源拼凑了这个代码,不知道如何在c中声明某些东西.任何建议将不胜感激.

解决方法

当widget的contextMenuPolicy是Qt :: CustomContextMenu,并且用户已经在窗口小部件上请求了一个上下文菜单时,会发出customContextMenuRequested.所以在你的窗口小部件的构造函数中,你可以调用setContextMenuPolicy,并将customContextMenuRequested连接到一个插槽来做一个自定义的上下文菜单.

在绘图空间的构造函数中：

this->setContextMenuPolicy(Qt::CustomContextMenu);
 
connect(this,SIGNAL(customContextMenuRequested(const QPoint &)),SLOT(ShowContextMenu(const QPoint &)));

ShowContextMenu插槽应该是plotspace的类成员,如：

void plotspace::ShowContextMenu(const QPoint &pos) 
{
   QMenu contextMenu(tr("Context menu"),this);
 
   QAction action1("Remove Data Point",this);
   connect(&action1,SIGNAL(triggered()),SLOT(removeDataPoint()));
   contextMenu.addAction(&action1);
 
   contextMenu.exec(mapToGlobal(pos));
}

c – 在Qt中右键单击事件以打开上下文菜单

解决方法

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