Linking error compiling customListWidget on emitting signal

sixeight

Why do I get a linker error on the following code:

custompatchlistwidget.h:

#ifndef CUSTOMPATCHLISTWIDGET_H
#define CUSTOMPATCHLISTWIDGET_H

#include <QListWidget>

class customPatchListWidget : public QListWidget
{
public:
    customPatchListWidget(QWidget *parent);

signals:
    void dragMovePatch(int sourceRow, int destRow);

protected:
    void dragEnterEvent(QDragEnterEvent *event);
    void dropEvent(QDropEvent *event);
};

#endif // CUSTOMPATCHLISTWIDGET_H

custompatchlistwidget.ccp:

#include "custompatchlistwidget.h"

#include <QDebug>
#include <QDragEnterEvent>
#include <QDragLeaveEvent>
#include <QDragMoveEvent>

customPatchListWidget::customPatchListWidget(QWidget *parent) : QListWidget(parent)
{
    Q_UNUSED(parent);

    setDragDropMode(QAbstractItemView::InternalMove);
    setDefaultDropAction(Qt::MoveAction);
}

void customPatchListWidget::dragEnterEvent ( QDragEnterEvent *event )
{
    if ( event->source() != this ) {
        setDragDropMode ( QAbstractItemView:: DragDrop );
               event->accept();
    } else {
        setDragDropMode ( QAbstractItemView::InternalMove );
        event->accept();
    }

}

void customPatchListWidget::dropEvent(QDropEvent *event)
{
    customPatchListWidget *source = (customPatchListWidget*) event->source();

    int sourceRow = source->currentRow();

    if (event->source() == this) {
        event->acceptProposedAction();
        emit dragMovePatch(sourceRow, currentRow());
    }
}

If I comment out the emit line, the code compiles fine. I have done exactly the same in a different custom listwidget which compiles fine. But this one will not work. I am at a loss...

Christian Ehrlicher

@sixeight said in Linking error compiling customListWidget on emitting signal:

Why do I get a linker error

You did not post which error you get. Since you want to emit a signal, you have to add Q_OBJECT to your class.

dheerendra

As @Christian-Ehrlicher already said Q_OBJECT is missing in the private section of your class. Please as programmer you are declaring the signal. Signals are implemented. Since Q_OBJECT macro is missing, your signal implementation is not there. Hence you are facing the issue.