利用Qt来实现一个时钟小程序

来源：互联网发布：太早遇到对的人知乎编辑：程序博客网时间：2024/05/17 09:37

要实现一个时钟小程序，我们首先想到需要以下的几个东西：

1. 时针

2.时针刻度

3.分针

4.分针刻度

5.秒针

要实现这个可以继承自QWidget，并在其中的paintEvent（QPaintEvent *event）Q_DECL_OVERLOAD;重载函数中来实现

具体代码如下：

#ifndef ANALOGCLOCK_H#define ANALOGCLOCK_H#include<QtWidgets>class AnalogClock : public QWidget{    Q_OBJECTpublic:    explicit AnalogClock(QWidget *parent = 0);    ~AnalogClock();signals:public slots:protected:    //重载函数，实现窗口的重绘    void paintEvent(QPaintEvent* evnet)Q_DECL_OVERRIDE;};#endif // ANALOGCLOCK_H

#include "analogclock.h"#include<QtWidgets>AnalogClock::AnalogClock(QWidget *parent) : QWidget(parent){    //构造函数，设置定时器    QTimer* timer = new QTimer(this);    connect(timer ,SIGNAL(timeout()) ,this , SLOT(update()) );    timer->start(1000);    setWindowTitle(tr("Analog Clock"));    resize(200 , 200);}AnalogClock::~AnalogClock(){}void AnalogClock::paintEvent(QPaintEvent *evnet){    //时针多边形    static const QPoint hourHand[3] = {        QPoint(7,8),        QPoint(-7,8),        QPoint(0,-40)    };    //分针多边形    static const QPoint minuteHand[3] = {        QPoint(7,8),        QPoint(-7,8),        QPoint(0, -70)    };    //秒针多边形    static const QPoint secondHand[3] = {      QPoint(7 , 8),        QPoint(-7 , 8),        QPoint(0 , -90)    };    //设置颜色    QColor hourColor(127 , 0 , 127);    QColor minuteColor(0 , 127 , 127 , 191);    QColor secondColor(0 ,0 , 127 );    int side = qMin(width() , height());    //获取当前时间    QTime time = QTime::currentTime();    QPainter painter(this);    painter.setRenderHint(QPainter::Antialiasing);    painter.translate(width()/2 , height()/2);    painter.scale(side/200.0 , side/200.0);    painter.setPen(Qt::NoPen);    painter.setBrush(hourColor);    painter.save();    //旋转painter    painter.rotate(30.0 * ((time.hour() + time.minute()/60.0)));    //画指针多边形    painter.drawConvexPolygon(hourHand , 3);    painter.restore();    painter.setPen(hourColor);//画时针的刻度    for(int i = 0 ; i < 12; ++i){        painter.drawLine(88 , 0 , 96 , 0);        painter.rotate(30.0);    }    painter.setPen(Qt::NoPen);    painter.setBrush(minuteColor);    painter.save();    painter.rotate(6.0 * (time.minute() + time.second()/60));    painter.drawConvexPolygon(minuteHand , 3);    painter.restore();    painter.setPen(minuteColor);    for(int j = 0 ; j < 60 ; ++j){        if((j %5) != 0)        {            painter.drawLine(92 , 0 , 96 , 0);        }        painter.rotate(6.0);    }    painter.setPen(Qt::NoPen);    painter.setBrush(secondColor);    painter.save();    painter.rotate(6.0 *(time.second()));    painter.drawConvexPolygon(secondHand , 3);   // painter.restore();     painter.restore();}

然后就可以在main中使用这个时钟类了，直接实例化一个对象就可以使用了

具体如下：

//#include "mainwindow.h"#include <QApplication>#include"analogclock.h"int main(int argc, char *argv[]){    QApplication a(argc, argv);    AnalogClock w;    w.show();    return a.exec();}

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