Qt 实现实时系统时间显示

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

int main(int argc, char *argv[])
{
QApplication a(argc, argv);
MainWindow w;
w.show();

return a.exec();
}

#ifndef MAINWINDOW_H
#define MAINWINDOW_H

#include <QMainWindow>

namespace Ui {
class MainWindow;
}

class MainWindow : public QMainWindow
{
Q_OBJECT

public:
explicit MainWindow(QWidget *parent = 0);
~MainWindow();

private:
Ui::MainWindow *ui;
public slots:
void timerUpdate(void);
};

#endif // MAINWINDOW_H

#include "mainwindow.h"
#include "ui_mainwindow.h"
#include <QTimer>
#include <qdatetime.h>

MainWindow::MainWindow(QWidget *parent) :
QMainWindow(parent),
ui(new Ui::MainWindow)
{
ui->setupUi(this);
QTimer *timer = new QTimer(this);
connect(timer,SIGNAL(timeout()),this,SLOT(timerUpdate()));
timer->start(1000);
}

MainWindow::~MainWindow()
{
delete ui;
}

void MainWindow::timerUpdate(void)
{
QDateTime time = QDateTime::currentDateTime();
QString str = time.toString("yyyy-MM-dd hh:mm:ss dddd");
ui->label->setText(str);
}