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));
}
