Qt实现简易时钟

QT  += core gui
 
greaterThan(QT_MAJOR_VERSION, 4): QT += widgets
 
CONFIG += c++11
 
# The following define makes your compiler emit warnings if you use
# any Qt feature that has been marked deprecated (the exact warnings
# depend on your compiler). Please consult the documentation of the
# deprecated API in order to know how to port your code away from it.
DEFINES += QT_DEPRECATED_WARNINGS
 
# You can also make your code fail to compile if it uses deprecated APIs.
# In order to do so, uncomment the following line.
# You can also select to disable deprecated APIs only up to a certain version of Qt.
#DEFINES += QT_DISABLE_DEPRECATED_BEFORE=0x060000 # disables all the APIs deprecated before Qt 6.0.0
 
SOURCES += \
 main.cpp \
 mainwindow.cpp
 
HEADERS += \
 mainwindow.h
 
FORMS += \
 mainwindow.ui
 
# Default rules for deployment.
qnx: target.path = /tmp/$${TARGET}/bin
else: unix:!android: target.path = /opt/$${TARGET}/bin
!isEmpty(target.path): INSTALLS += target
 
RESOURCES += \
 image.qrc

#ifndef MAINWINDOW_H
#define MAINWINDOW_H
 
#include <QMainWindow>
#include <QDateTime>
 
QT_BEGIN_NAMESPACE
namespace Ui { class MainWindow; }
QT_END_NAMESPACE
 
class MainWindow : public QMainWindow
{
 Q_OBJECT
 
public:
 MainWindow(QWidget *parent = nullptr);
 ~MainWindow();
 void paintEvent(QPaintEvent *event);
 bool showColon = false;
public slots:
 void countTime();
 
private:
 Ui::MainWindow *ui;
};
#endif // MAINWINDOW_H

#include "mainwindow.h"
#include "ui_mainwindow.h"
#include<QPainter>
#include<QTimer>
#include<QTime>
#include<QString>
 
MainWindow::MainWindow(QWidget *parent)
 : QMainWindow(parent)
 , ui(new Ui::MainWindow)
{
 ui->setupUi(this);
 
 QTimer *timer = new QTimer(this);
 connect(timer, SIGNAL(timeout()), this, SLOT(update()));
 connect(timer, SIGNAL(timeout()), this, SLOT(countTime()));
 timer->start(1000);
 countTime();
 
 setWindowTitle(tr("Clock_by_Xr"));
 setFixedSize(800, 400);
 
}
 
MainWindow::~MainWindow()
{
 delete ui;
}
 
void MainWindow::paintEvent(QPaintEvent *event){
 static QPoint hourHand[3] = {
  QPoint(5, 3),
  QPoint(-5, 3),
  QPoint(0, -30)
 };
 static QPoint minuteHand[3] = {
  QPoint(4, 6),
  QPoint(-4, 6),
  QPoint(0, -45)
 };
 static QPoint secondHand[3] = {
  QPoint(2, 10),
  QPoint(-2, 10),
  QPoint(0, -60)
 };
 
 
 //颜色
 QColor hourColor(0, 185, 211, 238);
 QColor minuteColor(0, 96, 123, 139);
 QColor secondColor(0, 176, 226, 255);
 
 int side = qMin(width(), height());
 QTime time = QTime::currentTime();
 
 QPainter painter(this);
 painter.setRenderHint(QPainter::Antialiasing);
 //表盘
 QBrush brush1(QColor(164,211,238));
 QPen pen1(QColor(164,211,238));
 painter.setBrush(brush1);
 painter.setPen(pen1);
 painter.drawEllipse(QPoint(200,200),200/3*2,200/3*2);
 
 QBrush brush2(QColor(245,245,245));
 QPen pen2(QColor(245,245,245));
 painter.setBrush(brush2);
 painter.setPen(pen2);
 painter.drawEllipse(QPoint(200,200),194/3*2,194/3*2);
 
 QBrush brush3(QColor(250,250,250));
 QPen pen3(QColor(250,250,250));
 painter.setBrush(brush3);
 painter.setPen(pen3);
 painter.drawEllipse(QPoint(200,200),183/3*2,183/3*2);
 
 QBrush brush4(QColor(255,255,255));
 QPen pen4(QColor(255,255,255));
 painter.setBrush(brush4);
 painter.setPen(pen4);
 painter.drawEllipse(QPoint(200,200),175/3*2,175/3*2);
 
 painter.setRenderHint(QPainter::Antialiasing);
 painter.translate(width()/4, height()/2);
 painter.scale(side/200.0, side/200.0);
 
 painter.setPen(Qt::NoPen);
 painter.setBrush(hourColor);
 
 painter.save();
 painter.rotate(30.0 * ((time.hour() + time.minute() / 60.0)));
 painter.drawConvexPolygon(hourHand, 3);
 painter.restore();
 
 //刻度
 painter.setPen(hourColor);
 for (int i = 0; i < 12; ++i) {
 
  painter.rotate(30.0);
  painter.drawLine(66,0,72,0);
  painter.drawText(-15, -65, 30, 30,Qt::AlignHCenter,QString::number(i+1));
 }
 
 //分钟
 painter.setPen(Qt::NoPen);
 painter.setBrush(minuteColor);
 
 painter.save();
 painter.rotate(6.0 * (time.minute() + time.second() / 60.0));
 painter.drawConvexPolygon(minuteHand, 3);
 painter.restore();
 
 painter.setPen(minuteColor);
 for (int j = 0; j < 60; ++j) {
  if ((j % 5) != 0)
   painter.drawLine(68, 0, 72, 0);
  painter.rotate(6.0);
 }
 
 //秒钟
 painter.setPen(Qt::NoPen);
 painter.setBrush(secondColor);
 
 painter.save();
 painter.rotate(6.0 * time.second());
 painter.drawConvexPolygon(secondHand, 3);
 painter.restore();
 
 painter.end();
}
 
void MainWindow::countTime(){
 QTime t = QTime::currentTime();
 QString text=t.toString("hh:mm:ss");
 if(showColon){
  text[2] = ':';
  text[5] = ':';
  showColon = false;
 }
 else{
  text[2] = ' ';
  text[5] = ' ';
  showColon = true;
 }
 ui->lcdNumber->display(text);
 ui->lcdNumber_2->display(text);
}