Qt实现简单动态时钟

本文实例为大家分享了Qt实现简单动态时钟的具体代码，供大家参考，具体内容如下

任务实现：

通过Qt语言使用计时器实现一个简单的动态时钟；

实现效果：

实现过程：

整体过程主要分为两个部分：

1.绘制一个表盘所需的元素：时分秒针，刻度，还可以插入钟面背景图片；
2.让所绘制的指针动起来（使用计时器并关联系统时间）；

整体代码：

dialog.h

#ifndef DIALOG_H
#define DIALOG_H

#include <QDialog>

QT_BEGIN_NAMESPACE
namespace Ui { class Dialog; }
QT_END_NAMESPACE

class Dialog : public QDialog
{
  Q_OBJECT

public:
  Dialog(QWidget *parent = nullptr);
  ~Dialog();

  void paintEvent(QPaintEvent *event);

  void drawSecond(QPainter *painter);

  void drawMinute(QPainter *painter);

  void drawHour(QPainter *painter);

  void drawClock(QPainter *painter);

private:
  Ui::Dialog *ui;
};
#endif // DIALOG_H

dialog.cpp

#include "dialog.h"
#include "ui_dialog.h"
#include <QPainter>
#include <QTime>
#include <QTimer>
#include <QPixmap>
#include <QPen>

Dialog::Dialog(QWidget *parent)
  : QDialog(parent)
  , ui(new Ui::Dialog)
{
  ui->setupUi(this);

  resize(959,959);

  setWindowTitle("My Clock");

  QTimer *timer = new QTimer(this);

  timer->start(1000);

  //信号的链接
  connect(timer,SIGNAL(timeout()),this,SLOT(update()));

}

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

void Dialog::paintEvent(QPaintEvent *event)
{
  QPainter painter(this);

  QPixmap map(":/Resrouse/Pic.jpg");

  QRect q(0,0,959,959);

  QRect q2(0,0,width(),height());

  painter.drawPixmap(q2,map,q);

  //防止图形走样
  painter.setRenderHint(QPainter::Antialiasing,true);

  //使得窗口可调节，图形随之变形
  painter.setWindow(0,0,200,200);

  //重新设置坐标轴的原点位置
  painter.translate(100,100);

  //调用绘制图像函数，分别绘制时分秒
  drawClock(&painter);
  drawSecond(&painter);
  drawMinute(&painter);
  drawHour(&painter);

}

void Dialog::drawSecond(QPainter *painter)
{

  static const QPoint Second[4]=
  {
    QPoint(2, 5),
    QPoint(0, 18),
    QPoint(-2, 5),
    QPoint(0, -90)
  };

  //获取当前系统时间currentTime();
  QTime time = QTime::currentTime();

  //设置绘制颜色
  painter->setBrush(Qt::red);
  painter->setPen(Qt::red);

  //save进行保存
  painter->save();

  //完成绘制（时间换算倾斜角度）
  painter->rotate(6.0*time.second());
  painter->drawConvexPolygon(Second,4);

  //ratate进行复位
  painter->restore();

}

void Dialog::drawMinute(QPainter *painter)
{

  static const QPoint Minute[4]=
  {
    QPoint(2, 5),
    QPoint(0, 16),
    QPoint(-2, 5),
    QPoint(0, -70)
  };

  QTime time = QTime::currentTime();

  painter->setBrush(Qt::blue);
  painter->setPen(Qt::blue);

  painter->save();

  painter->rotate(6.0*(time.minute()+time.second()/60.0));
  painter->drawConvexPolygon(Minute,4);

  painter->restore();

}

void Dialog::drawHour(QPainter *painter)
{
  static const QPoint Hour[4]=
  {
    QPoint(2, 5),
    QPoint(0, 13),
    QPoint(-2, 5),
    QPoint(0, -40)
  };

  QTime time = QTime::currentTime();

  painter->setBrush(Qt::yellow);
  painter->setPen(Qt::yellow);

  painter->save();

  painter->rotate(30.0*(time.hour()+time.minute()/60.0));
  painter->drawConvexPolygon(Hour,4);

  painter->restore();

}

void Dialog::drawClock(QPainter *painter)
{
  QPen pen;

  pen.setWidth(2);

  pen.setColor(Qt::white);

  painter->setPen(pen);

  //绘制钟表刻度盘和数字
  for (int i = 1; i <=60; ++i)
  {

    painter->save();

    painter->rotate(6*i);//坐标轴旋转6度

    //分别绘制长短线
    if (i % 5 == 0)
    {

      painter->drawLine(0, -98, 0, -82);
      painter->drawText(-20, -82, 40, 40,Qt::AlignHCenter | Qt::AlignTop,QString::number(i/5));
    }
    else
    {

      painter->drawLine(0, -98, 0, -88);
    }

    painter->restore();//绘制图形后复位坐标系
  }

}

表盘绘制：

使用paintEvent（）函数，以结构体形式来储存每一个指针的大小位置，并进行绘制；
下面用秒针的绘制作为例子：

void Dialog::drawSecond(QPainter *painter)
{

  static const QPoint Second[4]=
  {
    QPoint(3, 5),
    QPoint(0, 18),
    QPoint(-3, 5),
    QPoint(0, -90)
  };

  //获取当前系统时间currentTime();
  QTime time = QTime::currentTime();

  //设置绘制颜色
  painter->setBrush(Qt::red);
  painter->setPen(Qt::red);

  //save进行保存
  painter->save();

  //完成绘制（时间换算倾斜角度）
  painter->rotate(6.0*time.second());
  painter->drawConvexPolygon(Second,4);

  //ratate进行复位
  painter->restore();

}

调用时间：

设置计时器的时间为1000ms，即1s；

QTimer *timer = new QTimer(this);

timer->start(1000);

//信号的链接
connect(timer,SIGNAL(timeout()),this,SLOT(update()));

其他：

1.图片的插入：

map中内容可替换为自行导入的资源文件

QPixmap map(":/Resrouse/Pic.jpg");

QRect q(0,0,959,959);

QRect q2(0,0,width(),height());

painter.drawPixmap(q2,map,q);

2.绘制颜色的改变：

QPen pen;

//设置画笔的宽度
pen.setWidth(2); 

//设置画笔的颜色
pen.setColor(Qt::white);

//调用设置的画笔参数
painter->setPen(pen);

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