Linking issues with emiting a custom signal from a QGraphicsScene subclass?

[mrtof]

Hi, I am trying to emit a signal from a custom subclass of QGraphicsScene. I get the following errors:

"BoardScene::selected(int)", referenced from:
      BoardScene::select(int)   in boardscene.o
ld: symbol(s) not found
collect2: ld returned 1 exit status
make: *** [Msg.app/Contents/MacOS/Msg] Error 1
make: Leaving directory `/Users/tom/Documents/Qt/Msg-build-desktop'
The process "/usr/bin/make" exited with code 2.
Error while building project Msg (target: Desktop)
When executing build step 'Make'

"BoardScene::selected(int)", referenced from:
      BoardScene::select(int)   in boardscene.o
ld: symbol(s) not found
collect2: ld returned 1 exit status
make: *** [Msg.app/Contents/MacOS/Msg] Error 1
make: Leaving directory `/Users/tom/Documents/Qt/Msg-build-desktop'
The process "/usr/bin/make" exited with code 2.
Error while building project Msg (target: Desktop)
When executing build step 'Make'

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Why am I getting this error? What I want is that when a GraphicsPin is clicked, that it notifies the BoardScene (through bs->select(num)) of a click and then BoardScene emits the selected(num) signal.

boardscene.h:

#ifndef BOARDSCENE_H
#define BOARDSCENE_H
#include <QGraphicsScene>
#include <QGraphicsItem>
 
 
class BoardScene;
 
class GraphicsPin : public QGraphicsRectItem
{
 
public:
     GraphicsPin();
    ~GraphicsPin();
    void set(BoardScene* bs, int num,qreal x, qreal y,qreal size);
private:
    int num;
    QPen pen;
    QBrush brush;
    BoardScene* bs;
protected :
      void  hoverEnterEvent ( QGraphicsSceneHoverEvent * event );
      void  mousePressEvent ( QGraphicsSceneMouseEvent * event );
 
 
 
};
 
class BoardScene : public QGraphicsScene
{
    // Should I put Q_OBJECT here?
//Q_OBJECT
 
 
public:
    BoardScene();
    ~BoardScene();
protected:
    QPixmap pixmap;
    QGraphicsPixmapItem board;
    void load(QString file);
     void addPin(int num, qreal x, qreal y);
     int pinSize;
     GraphicsPin graphicsPin[128];
     int pins;
     int selectedPin;
 
private:
     QPen penNone;
     QBrush brushNone;
signals:
     void selected(int num);
 
 
public slots:
     void select(int num);
};
 
 
 
#endif // BOARDSCENE_H

#ifndef BOARDSCENE_H
#define BOARDSCENE_H
#include <QGraphicsScene>
#include <QGraphicsItem>


class BoardScene;

class GraphicsPin : public QGraphicsRectItem
{

public:
     GraphicsPin();
    ~GraphicsPin();
    void set(BoardScene* bs, int num,qreal x, qreal y,qreal size);
private:
    int num;
    QPen pen;
    QBrush brush;
    BoardScene* bs;
protected :
      void  hoverEnterEvent ( QGraphicsSceneHoverEvent * event );
      void  mousePressEvent ( QGraphicsSceneMouseEvent * event );



};

class BoardScene : public QGraphicsScene
{
    // Should I put Q_OBJECT here?
//Q_OBJECT


public:
    BoardScene();
    ~BoardScene();
protected:
    QPixmap pixmap;
    QGraphicsPixmapItem board;
    void load(QString file);
     void addPin(int num, qreal x, qreal y);
     int pinSize;
     GraphicsPin graphicsPin[128];
     int pins;
     int selectedPin;

private:
     QPen penNone;
     QBrush brushNone;
signals:
     void selected(int num);


public slots:
     void select(int num);
};



#endif // BOARDSCENE_H

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boardscene.cpp:

#include "boardscene.h"
#include "qdebug.h"
 
////// GRAPHICSPIN //////
 
GraphicsPin::GraphicsPin() {
    setAcceptHoverEvents(true);
    pen.setStyle(Qt::SolidLine);
    pen.setWidth(1);
    pen.setBrush(QColor(255,255,255));
    brush.setStyle(Qt::SolidPattern);
    brush.setColor(QColor(255,255,255));
 
    setPen(pen);
    setBrush(brush);
}
 
GraphicsPin::~GraphicsPin() {
 
}
 
void GraphicsPin::set(BoardScene *bs,int num,qreal x, qreal y,qreal size) {
    setRect(x,y,size,size);
    this->num = num;
    this->bs = bs;
}
 
 void GraphicsPin::hoverEnterEvent ( QGraphicsSceneHoverEvent * event ) {
     qDebug() << "GraphicsPin::hoverEnterEvent";
}
 
 void GraphicsPin::mousePressEvent(QGraphicsSceneMouseEvent * event ) {
     qDebug() << "GraphicsPin::mousePressEvent";
     if ( bs ) bs->select(num);
 
 }
 
 ////// BOARDSCENE //////
 
BoardScene::BoardScene()
{
 
  addItem(&board);
  selectedPin = -1;
 
}
 
 
BoardScene::~BoardScene() {
 
}
 
 
void BoardScene::select(int num) {
    if ( num != selectedPin ) {
        qDebug() << "BoardScene::select" << num;
        selectedPin = num;
        emit selected(num);
    }
}
 
void BoardScene::load(QString file) {
    pixmap.load(file);
    board.setPixmap(pixmap);
 
}
 
void BoardScene::addPin(int num, qreal x, qreal y) {
    graphicsPin[num].set(this,num,x,y,pinSize);
    addItem(&graphicsPin[num]);
}

#include "boardscene.h"
#include "qdebug.h"

////// GRAPHICSPIN //////

GraphicsPin::GraphicsPin() {
    setAcceptHoverEvents(true);
    pen.setStyle(Qt::SolidLine);
    pen.setWidth(1);
    pen.setBrush(QColor(255,255,255));
    brush.setStyle(Qt::SolidPattern);
    brush.setColor(QColor(255,255,255));

    setPen(pen);
    setBrush(brush);
}

GraphicsPin::~GraphicsPin() {

}

void GraphicsPin::set(BoardScene *bs,int num,qreal x, qreal y,qreal size) {
    setRect(x,y,size,size);
    this->num = num;
    this->bs = bs;
}

 void GraphicsPin::hoverEnterEvent ( QGraphicsSceneHoverEvent * event ) {
     qDebug() << "GraphicsPin::hoverEnterEvent";
}

 void GraphicsPin::mousePressEvent(QGraphicsSceneMouseEvent * event ) {
     qDebug() << "GraphicsPin::mousePressEvent";
     if ( bs ) bs->select(num);

 }

 ////// BOARDSCENE //////

BoardScene::BoardScene()
{

  addItem(&board);
  selectedPin = -1;

}


BoardScene::~BoardScene() {

}


void BoardScene::select(int num) {
    if ( num != selectedPin ) {
        qDebug() << "BoardScene::select" << num;
        selectedPin = num;
        emit selected(num);
    }
}

void BoardScene::load(QString file) {
    pixmap.load(file);
    board.setPixmap(pixmap);

}

void BoardScene::addPin(int num, qreal x, qreal y) {
    graphicsPin[num].set(this,num,x,y,pinSize);
    addItem(&graphicsPin[num]);
}

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Thank you for your help.

[wysota]

You are missing the Q_OBJECT macro in your scene class.

[mrtof]

You are missing the Q_OBJECT macro in your scene class.

With the macro I get even more errors:

Undefined symbols:
  "vtable for BoardScene", referenced from:
      BoardScene::~BoardScene()in boardscene.o
      BoardScene::~BoardScene()in boardscene.o
      BoardScene::~BoardScene()in boardscene.o
      BoardScene::BoardScene()in boardscene.o
      BoardScene::BoardScene()in boardscene.o
  "BoardScene::selected(int)", referenced from:
      BoardScene::select(int)   in boardscene.o
ld: symbol(s) not found
collect2: ld returned 1 exit status

Undefined symbols:
  "vtable for BoardScene", referenced from:
      BoardScene::~BoardScene()in boardscene.o
      BoardScene::~BoardScene()in boardscene.o
      BoardScene::~BoardScene()in boardscene.o
      BoardScene::BoardScene()in boardscene.o
      BoardScene::BoardScene()in boardscene.o
  "BoardScene::selected(int)", referenced from:
      BoardScene::select(int)   in boardscene.o
ld: symbol(s) not found
collect2: ld returned 1 exit status

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---

Added after 15 minutes:

I removed a class that I was conflicting with the build. Everything works now, thanks!

[ChrisW67]

Re-run qmake and then rebuild so that moc is run.