Counter widget

[eu.x]

Hi,

I'm trying to make a widget to handle time.

timer.h

#ifndef Timer_H
#define Timer_H
 
#include <QWidget>
class QLabel;
 
class Timer : public QWidget
{	
	Q_OBJECT
 
	public:
		Timer();
		int getHour();
		int getMinute();
		int getSecond();
 
		int secondValue() const;
 
		void show();
 
	public slots:
		void addSecond();
 
	signals:
		void secondChanged(int);
 
	private:
		int hour;
		int minute;
		int second;
 
		QLabel *l;
};
 
#endif

#ifndef Timer_H
#define Timer_H

#include <QWidget>
class QLabel;

class Timer : public QWidget
{	
	Q_OBJECT
	
	public:
		Timer();
		int getHour();
		int getMinute();
		int getSecond();
		
		int secondValue() const;
		
		void show();
		
	public slots:
		void addSecond();
	
	signals:
		void secondChanged(int);

	private:
		int hour;
		int minute;
		int second;
		
		QLabel *l;
};

#endif

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-----------------------------------------------------

timer.cpp

#include <QtGui>
#include "timer.h"
 
Timer::Timer() : QWidget()
{
	hour = 0;
	minute = 0;
	second = 0;
 
	l = new QLabel();
}
 
void Timer::addSecond()
{	
	second++;
 
	if(second == 60)
	{
		minute++;
		second = 0;
		if(minute == 60)
		{
			hour++;
			minute = 0;	
		}	
	}
 
	emit secondChanged(second);
}
 
int Timer::getHour()
{
	return hour;	
}
 
int Timer::getMinute()
{
	return minute;	
}
 
int Timer::getSecond()
{
	return second;	
}
 
int Timer::secondValue() const
{
	return second;	
}
 
void Timer::secondChanged(int secondValue)
{
	l->setNum(secondValue);	
}
 
void Timer::show()
{
	l->show();
}

#include <QtGui>
#include "timer.h"

Timer::Timer() : QWidget()
{
	hour = 0;
	minute = 0;
	second = 0;
	
	l = new QLabel();
}

void Timer::addSecond()
{	
	second++;
	
	if(second == 60)
	{
		minute++;
		second = 0;
		if(minute == 60)
		{
			hour++;
			minute = 0;	
		}	
	}
	
	emit secondChanged(second);
}

int Timer::getHour()
{
	return hour;	
}

int Timer::getMinute()
{
	return minute;	
}

int Timer::getSecond()
{
	return second;	
}

int Timer::secondValue() const
{
	return second;	
}

void Timer::secondChanged(int secondValue)
{
	l->setNum(secondValue);	
}

void Timer::show()
{
	l->show();
}

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I'm getting this error:

debug\moc_timer.o(.text+0x1e0): In function `ZN5Timer13secondChangedEi':
C:/Projetos/backlog/debug/moc_timer.cpp:77: multiple definition of `Timer::secon
dChanged(int)'
debug\timer.o(.text+0x46a):C:/Projetos/backlog/timer.cpp:52: first defined here
collect2: ld returned 1 exit status
mingw32-make[1]: *** [debug\backlog.exe] Error 1
mingw32-make[1]: Leaving directory `C:/Projetos/backlog'
mingw32-make: *** [debug] Error 2

What should I do?!?

[jpn]

You don't implement function body for signals (the meta object compiler does it for you behind the curtains). So the declaration of secondChanged() is enough.

PS. Please use [ code ] -tags around code blocks to make them more readable.

[eu.x]

So how do I change values on other objects? For example, I need to update a QLabel everytime secondChanged signal is called.

My new code is:

timer.h

#ifndef Timer_H
#define Timer_H
 
#include <QWidget>
class QLabel;
 
class Timer : public QWidget
{	
	Q_OBJECT
 
	public:
		Timer();
		int getHour();
		int getMinute();
		int getSecond();
 
		int secondValue() const;
 
		void show();
 
	public slots:
		void addSecond();
 
	signals:
		void secondChanged(int);
 
	private:
		int hour;
		int minute;
		int second;
 
		QLabel *l;
};
 
#endif

#ifndef Timer_H
#define Timer_H

#include <QWidget>
class QLabel;

class Timer : public QWidget
{	
	Q_OBJECT
	
	public:
		Timer();
		int getHour();
		int getMinute();
		int getSecond();
		
		int secondValue() const;
		
		void show();
		
	public slots:
		void addSecond();
	
	signals:
		void secondChanged(int);

	private:
		int hour;
		int minute;
		int second;
		
		QLabel *l;
};

#endif

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-----------------------------------------------------------

timer.cpp

#include <QtGui>
#include "timer.h"
 
Timer::Timer() : QWidget()
{
	hour = 0;
	minute = 0;
	second = 0;
 
	l = new QLabel();
}
 
void Timer::addSecond()
{	
	second++;	
	if(second == 60)
	{
		minute++;
		second = 0;
		if(minute == 60)
		{
			hour++;
			minute = 0;	
		}	
	}	
	emit secondChanged(second);
}
 
int Timer::getHour()
{
	return hour;	
}
 
int Timer::getMinute()
{
	return minute;	
}
 
int Timer::getSecond()
{
	return second;	
}
 
int Timer::secondValue() const
{
	return second;	
}
 
void Timer::show()
{
	l->show();
}

#include <QtGui>
#include "timer.h"

Timer::Timer() : QWidget()
{
	hour = 0;
	minute = 0;
	second = 0;
	
	l = new QLabel();
}

void Timer::addSecond()
{	
	second++;	
	if(second == 60)
	{
		minute++;
		second = 0;
		if(minute == 60)
		{
			hour++;
			minute = 0;	
		}	
	}	
	emit secondChanged(second);
}

int Timer::getHour()
{
	return hour;	
}

int Timer::getMinute()
{
	return minute;	
}

int Timer::getSecond()
{
	return second;	
}

int Timer::secondValue() const
{
	return second;	
}

void Timer::show()
{
	l->show();
}

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-----------------------------------------------

main.cpp

...
Timer *t = new Timer();			
QTimer *qTimer = new QTimer();
QObject::connect(qTimer, SLOT(timeout()), t, SIGNAL(addSecond()));
QObject::connect(t, SLOT(secondChanged(int)), l, SIGNAL(setNum(int)));
qTimer->start(1000);
l->show();
...

...
Timer *t = new Timer();			
QTimer *qTimer = new QTimer();
QObject::connect(qTimer, SLOT(timeout()), t, SIGNAL(addSecond()));
QObject::connect(t, SLOT(secondChanged(int)), l, SIGNAL(setNum(int)));
qTimer->start(1000);
l->show();
...

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[wysota]

I'd suggest using the timerEvent here instead of a standalone QTimer object.

[eu.x]

I'd suggest using the timerEvent here instead of a standalone QTimer object.

Do you have some example?

[wysota]

Well, your widget is so simple it might serve as an example

Please take a look at QObject::timerEvent() reference. It has all you need along an example use of startTimer() and timerEvent().

[jacek]

For example, I need to update a QLabel everytime secondChanged signal is called.

You don't call signals --- you emit them. If you want to react on a signal, you have to connect it to a slot and do what you need in that slot.

QObject::connect(qTimer, SLOT(timeout()), t, SIGNAL(addSecond()));
QObject::connect(t, SLOT(secondChanged(int)), l, SIGNAL(setNum(int)));

It should be:

QObject::connect( qTimer, SIGNAL(timeout()), t, SLOT(addSecond()) );
QObject::connect( t, SIGNAL(secondChanged(int)), l, SLOT(setNum(int)) );

QObject::connect( qTimer, SIGNAL(timeout()), t, SLOT(addSecond()) );
QObject::connect( t, SIGNAL(secondChanged(int)), l, SLOT(setNum(int)) );

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[eu.x]

Thank you jacek, I was confusing slots and signals.