Qt学习 第10节：获取系统时间

 

#ifndef TIME_H
#define TIME_H

#include <QWidget>
#include <QLabel>
#include <QPushButton>
#include <QVBoxLayout>
#include <QString>
#include <QTime>

class Time : public QWidget
{
    Q_OBJECT

public:
    Time(QWidget *parent = 0);
    ~Time();
private:
    QString string;
    QLabel* label;
    QPushButton* button;
public slots://自定义槽函数
    void ShowTime(void);
signals://自定义信号函数，只需要声明，不能写定义
    void mySignal(const QString&);
};

#endif // TIME_H

#include "Time.h"
#include <QDebug>
Time::Time(QWidget *parent)
    : QWidget(parent)
{
    this->resize(300,200);
    label = new QLabel(this);
    label->setFrameStyle(QFrame::Panel|QFrame::Sunken);//面板|凹陷
    label->setAlignment(Qt::AlignCenter|Qt::AlignVCenter);//水平|垂直居中
    QFont font;
    font.setPointSize(20);//调整字体大小
    label->setFont(font);

    button = new QPushButton("Current Time",this);
    button->setFont(font);//保持字体大小一致

//    connect(button,SIGNAL(clicked(void)),this,SLOT(ShowTime(void)));
    connect(button,SIGNAL(clicked(void)),this,SLOT(ShowTime(void)));
    //通过自定义信号，触发label的setText槽函数执行
    connect(this,SIGNAL(mySignal(QString)),label,SLOT(setText(QString)));

    QVBoxLayout* layout = new QVBoxLayout(this);
    layout->addWidget(label);
    layout->addWidget(button);
    this->setLayout(layout);
}

void Time::ShowTime(void)
{
    qDebug() << "ShowTime";
    QTime time = QTime::currentTime();//获取当前时间
    string = time.toString("hh:mm:ss");//把时间按指定格式转为字符串
    //string = time.toString(Qt::TextDate);//把时间转为字符串
    //label->setText(string);//显示时间字符串
    emit mySignal(string);//emit是qt关键字，标记发射信号
}

Time::~Time()
{

}

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

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

    return a.exec();
}