#ifndef MAINWINDOW_H
#define MAINWINDOW_H
#include <QMainWindow>
#include <mydialog.h>
#include <QLabel>
namespace Ui {
class MainWindow;
}
class MainWindow : public QMainWindow
{
  Q_OBJECT
public:
  explicit MainWindow(QWidget *parent = 0);
  ~MainWindow();
private slots:
  void on_actionNew_Window_triggered();
  void time_update(); //時(shí)間更新槽函數(shù)，狀態(tài)欄顯示時(shí)間
private:
  Ui::MainWindow *ui;
  QLabel *currentTimeLabel; // 先創(chuàng)建一個(gè)QLabel對象
  MyDialog *mydialog;
};
#endif // MAINWINDOW_H

#include "mainwindow.h"
#include "ui_mainwindow.h"
#include "mydialog.h"
#include <QLabel>
#include <QDateTime>
#include <QTimer>
#include <QString>
MainWindow::MainWindow(QWidget *parent) :
  QMainWindow(parent),
  ui(new Ui::MainWindow)
{
  ui->setupUi(this);
  currentTimeLabel = new QLabel; // 創(chuàng)建QLabel控件
  ui->statusBar->addWidget(currentTimeLabel); //在狀態(tài)欄添加此控件
  QTimer *timer = new QTimer(this);
  timer->start(1000); //每隔1000ms發(fā)送timeout的信號(hào)
  connect(timer, SIGNAL(timeout()),this,SLOT(time_update()));
}
MainWindow::~MainWindow()
{
  delete ui;
}
void MainWindow::on_actionNew_Window_triggered()
{
  mydialog = new MyDialog;
  mydialog->show();
}
void MainWindow::time_update()
{
  //[1] 獲取時(shí)間
  QDateTime current_time = QDateTime::currentDateTime();
  QString timestr = current_time.toString( "yyyy年MM月dd日 hh:mm:ss"); //設(shè)置顯示的格式
  currentTimeLabel->setText(timestr); //設(shè)置label的文本內(nèi)容為時(shí)間
}

#include <QTimer>

//日期/時(shí)間顯示
QTimer *timer = new QTimer(this);
connect(timer,SIGNAL(timeout()),this,SLOT(timerUpdate()));
timer->start(1000);

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