QT 时钟例子（可以自己设置时间）

#include<QRectF> #include<QTimer> #include<QTime> #include<QPainter> #include<QPoint> #include<QColor> #include<QFont> #include<QtMath> #include "clock.h" clock::clock(QWidget *parent) : QWidget(parent) { // The QTimer class provides a high-level programming interface for timers. // To use it, create a QTimer, connect its timeout() signal to the appropriate slots, and call start(). // From then on, it will emit the timeout() signal at constant intervals. timer1=new QTimer(this); connect(timer1,SIGNAL(timeout()),this,SLOT(newtime())); timer1->start(1000); timer=new QTimer(this); connect(timer,SIGNAL(timeout()),this,SLOT(update())); timer->start(1000); setWindowTitle(tr("clock")); state=0; hour=0; minute=0; second=0; // Constructs a size with the given width and height. resize(300,300); } clock::~clock() { } void clock::paintEvent(QPaintEvent *) { static const QPoint hourHand[3]={ QPoint(3,8), QPoint(-3,8), QPoint(0,-40) }; static const QPoint minuteHand[3]={ QPoint(3,8), QPoint(-3,8), QPoint(0,-70) }; static const QPoint secondHand[3]={ QPoint(3,8), QPoint(-3,8), QPoint(0,-90) }; // QColor::QColor(int r, int g, int b, int a = 255) // Constructs a color with the RGB value r, g, b,（red,green,blue） and the alpha-channel (transparency)透明化 value of a. // The color is left invalid if any of the arguments are invalid. QColor hourcolor(127,0,127); QColor minuteColor(0,127,127,191); QColor secondColor(127,127,0,130); int side=qMin(width(),height()); QTime time=QTime::currentTime(); QPainter painter(this); painter.setRenderHint(QPainter::Antialiasing); // void QPainter::translate(qreal dx, qreal dy) // This is an overloaded function. // Translates the coordinate system by the vector (dx, dy). painter.translate(width()/2,height()/2); painter.scale(side/200.0,side/200.0); //hour painter.setPen(Qt::NoPen); // void QPainter::setBrush(Qt::BrushStyle style) // This is an overloaded function. // Sets the painter's brush to black color and the specified style. painter.setBrush(hourcolor); painter.save(); if(state==0) painter.rotate(30.0*(time.hour()+(time.minute()/60.0))); else painter.rotate(30.0*(hour+minute/60.0)); painter.drawConvexPolygon(hourHand,3); //恢复到save() painter.restore(); painter.setPen(hourcolor); for(int i=0;i<12;++i) { painter.drawLine(88,0,96,0); painter.rotate(30.0); } //绘制小时文本 int radius=100; QFont font=painter.font(); font.setBold(true); painter.setFont(font); int pointSize=font.pointSize(); int nHour=0; for(int i=0;i<12;++i) { nHour=i+3; if(nHour>12) nHour-=12; painter.drawText(textRectF(radius*0.8,pointSize,i*30),Qt::AlignCenter,QString::number(nHour)); } //minute painter.setPen(Qt::NoPen); painter.setBrush(minuteColor); painter.save(); if(state==0) painter.rotate(6*(time.minute()+time.second()/60.0)); else painter.rotate(6*(minute+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(92,0,96,0); painter.rotate(6.0); } //second painter.setPen(Qt::NoPen); painter.setBrush(secondColor); painter.save(); if(state==0) painter.rotate(6*time.second()); else painter.rotate(6*second); painter.drawConvexPolygon(secondHand,3); painter.restore(); // painter.setPen(secondColor); // for(int j=0;j<60;++j) // { // painter.drawLine(92,0,96,0); // painter.rotate(6); // } } QRectF clock::textRectF(double radius,int pointSize,double angle) { QRectF rectF; rectF.setX(radius*qCos(angle*M_PI/180.0) - pointSize*2); rectF.setY(radius*qSin(angle*M_PI/180.0) - pointSize/2.0); rectF.setWidth(pointSize*4); rectF.setHeight(pointSize); return rectF; } void clock::newtime() { if(state==1){ ++second; if(second==60) { ++minute; second=0; } if(minute==60){ ++hour; minute=0; } if(hour>12) hour-=12; }}