为什么不会用Q_OBJECT宏编译(链接)到位? [英] Why won't this compile (link) with the Q_OBJECT macro in place?
问题描述
我使用PyQt制作了一个项目的原型,并使它在那里工作,现在我试图将其转换为C ++,并有一些问题。
I made a prototype of a project with PyQt and made it work there, now I'm trying to convert it to C++ and am having some problems.
我不把Q_OBJECT宏,它编译和工作,但如果我注释掉,我得到以下错误:
If I don't put the Q_OBJECT macro in, it compiles and works, but if I comment it out, I get the following errors:
Undefined symbols:
"vtable for MapView", referenced from:
MapView::~MapView()in mapview.o
MapView::~MapView()in mapview.o
MapView::MapView(QObject*)in mapview.o
MapView::MapView()in mapview.o
"MapView::staticMetaObject", referenced from:
MapView::MapView(QObject*)in mapview.o
MapView::MapView()in mapview.o
这是标题:
#ifndef MAPVIEW_H
#define MAPVIEW_H
#include <QtGui>
#include <QObject>
class MapView : public QGraphicsScene
{
//Q_OBJECT
public:
MapView();
explicit MapView(QObject *parent = 0);
QGraphicsPixmapItem *mappixmap;
~MapView();
private:
bool dragging;
float offsetX, offsetY, downoffsetX, downoffsetY;
protected:
void mousePressEvent(QGraphicsSceneMouseEvent *event);
void mouseMoveEvent(QGraphicsSceneMouseEvent *event);
void mouseReleaseEvent(QGraphicsSceneMouseEvent *event);
};
#endif // MAPVIEW_H
我只是在这里省略Q_OBJECT宏?
Secondary question is will Bad Things happen if I just omit the Q_OBJECT macro here?
是的,我知道这是愚蠢的调用QGraphicsScene一个视图。
And yes, I'm aware of that it's stupid to call a QGraphicsScene a "view".
推荐答案
这种错误通常发生在你添加 Q_OBJECT
宏并忘记重新运行 moc
。如果使用 qmake
,只需在添加宏后运行 make qmake
。
This kind of errors usually happen when you add the Q_OBJECT
macro and forget to rerun moc
. If you use qmake
, just run make qmake
after you added the macro.
对于你的第二个问题:在没有 Q_OBJECT
宏的情况下,你将不能使用信号/槽(以及其他)。有关此问题的详情,请参见文档。
As for your second question: you won't be able to use signals/slots (among other things) without the Q_OBJECT
macro. See the docs for more information about this.
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