Clickable Qlabel

[lewis]

Hi, I want to add the clicked() signal to a QLabel.

Can any1 point me the right direction to take?

[jpn]

Override QWidget::mousePressEvent() and/or QWidget::mouseReleaseEvent().
Emit the signal whenever you feel it's appropriate..

[lewis]

Im not sure I understand what you mean.

How and where can i override that event?

Is that a virtual function?

[wysota]

Hi, I want to add the clicked() signal to a QLabel.

Can any1 point me the right direction to take?

You can copy the code from wwActiveLabel. It should work fine without any changes (maybe one change is required, as widgets in Qt4 don't take the name argument in their constructors anymore).

[lewis]

Ill use that, but only if Im not able to make it myself quickly enough... I'd like to learn how to , thx tho

[lewis]

I get errors like these when using wwActiveLabel:

error C2027: use of undefined type 'QMouseEvent': see declaration of 'QMouseEvent'
error C2227: left of '->button' must point to class/struct/union/generic type

if i include QMouseEvent, i get linking errors.

im using qt 4.1.4 commercial

[wysota]

What kind of errors do you get?

This compiles fine:

/***************************************************************************
 *   Copyright (C) 2004 by Witold Wysota                                   *
 *   wysota@wysota.eu.org                                                  *
 *                                                                         *
 ***************************************************************************/
#ifndef WWCLASSES_H
#define WWCLASSES_H
 
#include <QLabel>
#include <QTimer>
#include <QPoint>
 
/**
 * @class wwActiveLabel
 * @brief Label with mouse click and mouse move support
 *
 *
 */
class wwActiveLabel : public QLabel
{
Q_OBJECT
public:
    wwActiveLabel(QWidget *parent = 0);    ///< default constructor
    ~wwActiveLabel();
signals:
    void doubleClicked();                                        ///< double click with LMB
    void clicked();                                              ///< single click with LMB
    void pressed();                                              ///< LMB pressed
    void released();                                             ///< LMB released
    void mouseOver();                                            ///< mouse pointer just entered the widget
    void mouseOut();                                             ///< mouse pointer just left the widget
protected:
    void mouseDoubleClickEvent ( QMouseEvent * e );
    void mousePressEvent( QMouseEvent *e);
    void mouseReleaseEvent( QMouseEvent *e);
    void enterEvent(QEvent *);
    void leaveEvent(QEvent *);
    bool hitLabel(const QPoint &p);
    bool m_pressed;                   
};
 
#endif

/***************************************************************************
 *   Copyright (C) 2004 by Witold Wysota                                   *
 *   wysota@wysota.eu.org                                                  *
 *                                                                         *
 ***************************************************************************/
#ifndef WWCLASSES_H
#define WWCLASSES_H

#include <QLabel>
#include <QTimer>
#include <QPoint>

/**
 * @class wwActiveLabel
 * @brief Label with mouse click and mouse move support
 *
 *
 */
class wwActiveLabel : public QLabel
{
Q_OBJECT
public:
    wwActiveLabel(QWidget *parent = 0);    ///< default constructor
    ~wwActiveLabel();
signals:
    void doubleClicked();                                        ///< double click with LMB
    void clicked();                                              ///< single click with LMB
    void pressed();                                              ///< LMB pressed
    void released();                                             ///< LMB released
    void mouseOver();                                            ///< mouse pointer just entered the widget
    void mouseOut();                                             ///< mouse pointer just left the widget
protected:
    void mouseDoubleClickEvent ( QMouseEvent * e );
    void mousePressEvent( QMouseEvent *e);
    void mouseReleaseEvent( QMouseEvent *e);
    void enterEvent(QEvent *);
    void leaveEvent(QEvent *);
    bool hitLabel(const QPoint &p);
    bool m_pressed;                   
};

#endif

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***************************************************************************
 *   Copyright (C) 2004 by Witold Wysota                                   *
 *   wysota@wysota.eu.org                                                  *
 *                                                                         *
 ***************************************************************************/
#include "wwclasses.h"
#include <QMouseEvent>
 
wwActiveLabel::wwActiveLabel(QWidget *parent) : QLabel(parent) {
    m_pressed = false;
    setText("wwActiveLabel");
}
wwActiveLabel::~wwActiveLabel() {}
void wwActiveLabel::mouseDoubleClickEvent( QMouseEvent * e ) {
    if(e->button() == Qt::LeftButton)
        emit doubleClicked();
    QLabel::mouseDoubleClickEvent(e);
}
void wwActiveLabel::mousePressEvent( QMouseEvent * e ) {
    if(e->button() == Qt::LeftButton) {
        m_pressed = true;
    } else
        m_pressed = false;
    emit pressed();
}
void wwActiveLabel::mouseReleaseEvent( QMouseEvent * e ) {
    if(m_pressed && e->button() == Qt::LeftButton && hitLabel(e->pos()))
        emit clicked();
    m_pressed = false;
    emit released();
 
}
void wwActiveLabel::enterEvent( QEvent *e ) {
    QLabel::enterEvent(e);
    emit mouseOver();
}
void wwActiveLabel::leaveEvent( QEvent *e ) {
    QLabel::leaveEvent(e);
    emit mouseOut();
}
bool wwActiveLabel::hitLabel( const QPoint & p ){
    return rect().contains(p);
}

***************************************************************************
 *   Copyright (C) 2004 by Witold Wysota                                   *
 *   wysota@wysota.eu.org                                                  *
 *                                                                         *
 ***************************************************************************/
#include "wwclasses.h"
#include <QMouseEvent>

wwActiveLabel::wwActiveLabel(QWidget *parent) : QLabel(parent) {
    m_pressed = false;
    setText("wwActiveLabel");
}
wwActiveLabel::~wwActiveLabel() {}
void wwActiveLabel::mouseDoubleClickEvent( QMouseEvent * e ) {
    if(e->button() == Qt::LeftButton)
        emit doubleClicked();
    QLabel::mouseDoubleClickEvent(e);
}
void wwActiveLabel::mousePressEvent( QMouseEvent * e ) {
    if(e->button() == Qt::LeftButton) {
        m_pressed = true;
    } else
        m_pressed = false;
    emit pressed();
}
void wwActiveLabel::mouseReleaseEvent( QMouseEvent * e ) {
    if(m_pressed && e->button() == Qt::LeftButton && hitLabel(e->pos()))
        emit clicked();
    m_pressed = false;
    emit released();

}
void wwActiveLabel::enterEvent( QEvent *e ) {
    QLabel::enterEvent(e);
    emit mouseOver();
}
void wwActiveLabel::leaveEvent( QEvent *e ) {
    QLabel::leaveEvent(e);
    emit mouseOut();
}
bool wwActiveLabel::hitLabel( const QPoint & p ){
    return rect().contains(p);
}

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[lewis]

Of course i had linking errors, i forgot to add it to my .pro file and regenerate the project file!!! dumb me!

[wysota]

Of course i had linking errors, i forgot to add it to my .pro file and regenerate the project file!!! dumb me!

If you use wwActiveLabel in a commercial product, please put a copyright notice somewhere in its docs and/or in the "about" window (if your app has one).

[lewis]

its not for commercial use, its only a little educationnal game that will be used inside a small non-profit organization.

Thx for ur wwActiveLabel widget!

[Oleg S]

Hi, I want to add the clicked() signal to a QLabel.

Can any1 point me the right direction to take?

Hi Lewis, this is Oleg S, I have the same problem that you, how did you solve it?

These are the messages errors:

error C2027: use of undefined type 'QMouseEvent'
c:\qt4.4.0\src\gui\kernel\qwidget.h(77) : see declaration of 'QMouseEvent'


error C2227: left of '->pos' must point to class/struct/union/generic type

Thanks so much!!

[jpn]

Oleg S,

#include <QMouseEvent>

#include <QMouseEvent>

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