Qt编程实现小时钟

Z时代
2024-01-10
分类：IT

Hello World! 学习编程语言的最简单最经典的小程序，当然Qt也不例外。在学习画图时，我觉得写个时钟小程序也是个比较好的开始。在之前的《Matlab及Java小时》一文中，我也从写时钟程序作为学习画图的开始。三者之间的不同点在于，matlab是通过while循环来进行重绘，Java和Qt事件来处理。实时显示时钟，都是通过改变指针与坐标轴的相对位置来实现的。前两者都是改变指针，而Qt是旋转坐标轴。具体代码如下：

1.widget.h文件


#ifndef WIDGET_H
#define WIDGET_H
#include <QWidget>
namespace Ui {
class Widget;
}
class Widget : public QWidget
{
 Q_OBJECT
public:
 explicit Widget(QWidget *parent = 0);
 ~Widget();
private:
 Ui::Widget *ui;
protected:
 void paintEvent(QPaintEvent *event);//添加重绘事件
};
#endif // WIDGET_H

2.main.cpp


#include <QtGui/QApplication>
#include "widget.h"
#include<QTextCodec>
#include<QPainter>
#include<QtGui>
#include<QDebug>
int main(int argc, char *argv[])
{
 QApplication a(argc, argv);
 QTextCodec::setCodecForTr(QTextCodec::codecForLocale());
 Widget w;
 w.show();
 return a.exec();
}

3.widget.cpp


#include "widget.h"
#include "ui_widget.h"
#include<QPainter>
#include<QtGui>
#include<QDebug>
#include<QFont>
Widget::Widget(QWidget *parent) :
 QWidget(parent),
 ui(new Ui::Widget)
{
 ui->setupUi(this);
 QTimer *timer = new QTimer(this);//创建一秒定时器
 connect(timer, SIGNAL(timeout()), this, SLOT(update()));//信号与槽关联
 timer->start(1000);
 setWindowTitle(tr("我的时钟--designed by TW"));
}
Widget::~Widget()
{
 delete ui;
}
void Widget::paintEvent(QPaintEvent *event)
{
 int side = qMin(width(), height());//获取窗口的较短边的值
 QPainter painter(this);//指定画图设备
 painter.fillRect(rect(),Qt::yellow);//设置背景色
 painter.setRenderHint(QPainter::Antialiasing);//开启抗锯齿
 painter.translate(width() / 2, height() / 2);//将坐标移到窗口正中心
 painter.scale(side / 200.0, side / 200.0);//进行缩放
 QPen pen;//设置画笔的，宽度，样式，颜色
 pen.setWidth(2);
 pen.setStyle(Qt::SolidLine);
 pen.setColor(Qt::red);
 painter.setPen(pen);
 for (int i = 0; i < 12; ++i) //画表盘时针刻度
 {
 painter.drawLine(87, 0, 95, 0);
 painter.rotate(30);//将坐标进行顺时针选择30度
 }
 pen.setWidth(1);
 pen.setColor(Qt::black);
 painter.setPen(pen);
 for (int i = 0; i < 60; ++i) //画表盘时针刻度
 {
 if(i%5!=0)
  painter.drawLine(90, 0, 95, 0);
 painter.rotate(6);
 }
 pen.setColor(Qt::black);
 painter.setPen(pen);
 QFont font("Century");
 painter.setFont(font);
 //标时刻的数值
 painter.drawText(-6,-75,tr("12"));
 painter.drawText(-3,80,tr("6"));
 painter.drawText(75,5,tr("3"));
 painter.drawText(-80,5,tr("9"));
 painter.drawArc(-3,-3,6,6,0,360*16);//画中心小圆环
 /////////////////////////////////////
 QTime time = QTime::currentTime();//获取当前系统时间
// qDebug()<<time.hour();
// qDebug()<<time.minute();
// qDebug()<<time.second();
 //画时针
 painter.save();//在旋转坐标系前，保存原来坐标系
 painter.rotate(30.0 * ((time.hour() + time.minute() / 60.0)));
 pen.setColor(Qt::green);
 pen.setWidth(4);
 painter.setPen(pen);
 painter.drawLine(0,0,0,-60);
 painter.restore();//在旋转坐标系后，恢复原来坐标系
 //画分针
 painter.save();
 painter.rotate(6.0 * (time.minute() + time.second() / 60.0));
 pen.setColor(Qt::blue);
 pen.setWidth(2);
 painter.setPen(pen);
 painter.drawLine(0,0,0,-80);
 painter.restore();
 //画秒针
 painter.save();
 painter.rotate(6.0 *time.second() );
 pen.setColor(Qt::red);
 pen.setWidth(1);
 painter.setPen(pen);
 //秒针形状由两条直线和一个小圆环组成
 painter.drawArc(-3,-66,6,6,0,360*16);
 painter.drawLine(0,20,0,-60);
 painter.drawLine(0,-66,0,-85);
 painter.restore();
}