[Qt 练习]QTimer

clock.h

#ifndef DIGITALCLOCK_H
#define DIGITALCLOCK_H
#include <QLCDNumber>
class DigitalClock:public QLCDNumber
{
public:
     DigitalClock(QWidget *parent = 0);

protected:
     void timerEvent(QTimerEvent *);

private:
     bool isColon;

};
#endif // DIGITALCLOCK_H

 

clock.cpp

#include "DigitalClock.h"
#include <QDateTime>
DigitalClock::DigitalClock(QWidget *parent):QLCDNumber(parent)
{
    this->isColon = false;
    this->setFrameStyle(QFrame::Panel | QFrame::Raised);
    this->setNumDigits(11);
    QObject::startTimer(500);
}

void DigitalClock::timerEvent(QTimerEvent *)
{
    isColon = !isColon;
    QString timeString = QTime::currentTime().toString().left(5);
    QDate date = QDate::currentDate();
    QString dateString;
    dateString.sprintf("%2d-%2d",date.month(), date.day());
    QString displayString = timeString + dateString;
    if(!isColon)
    {
       displayString[2] = ' ';
    }
    display(displayString);
}

main.cpp

#include "DigitalClock.h"
#include <QApplication>

int main(int argc, char **argv)
{
    QApplication app(argc, argv);
    DigitalClock *clock = new DigitalClock;
    clock->resize(500,80);
    clock->setWindowTitle("QTimer");
    clock->show();
    return app.exec();
}