• 額，忘記了哪位哲人說過：“站在巨人的肩膀上，我們能看得更高!”嗯，大概就是這個意思了。這兩天學(xué)習(xí)“一去二三里”大神博客里的Qt繪圖事件，其中有一篇涉及到畫圓盤，突然有想法，寫個簡易的抽獎小demo。了解了這種抽獎的原理和機制后，馬丹，幸好沒有買過各種彩票之類的，各種獎項的概率值分明是設(shè)置出來的嘛(我程序里是寫死了)..好，先截個圖:

• 簡易能用。。哈哈
• 頭文件代碼如下:

#ifndef WIDGET_H
#define WIDGET_H
#include <QWidget>
#include <QPainter>
#include <QRadialGradient>
#include <QPainterPath>
#include <QTimer>
#include <QDebug>
#include <QMouseEvent>
#include <QPushButton>
#include <QTime>
#include <QLabel>
#include <QLineEdit>
#include <QMap>
#include <QMapIterator>
#define MAX_CIRCLE  1800
namespace Ui {
class Widget;
}
class Widget : public QWidget
{Q_OBJECT
public:explicit Widget(QWidget *parent = 0);~Widget();void gradientArc(QPainter *painter,int radius,int startAngle,int angleLength,int arcHeight,QRgb color);
public slots:void updatePaint();void btnClicked();void reResult(int re);void stopRotate();
signals:void sigResult(int re);
private:Ui::Widget *ui;int m_nRotationAngle;int m_nRo;quint32 m_T;QString m_Re;QTimer *m_timer;QTimer *timer;int m_i;QPushButton *m_btn;bool isDefault;enum Awards{Spe = 3,First = 7,Second = 5,Third = 2,Luck_Fir = 6,Luck_Sec = 1,ThanK_Fir = 4,Thank_Sec = 0,};Awards m_award;QLabel *m_labTr;QLabel *m_labRe;QLineEdit *m_ldeRe;QMap<int,QString> m_map;QMap<int, QString> returnResult(int re);static QString showAwards(Awards award);void stopInit();int getRand();
protected:void paintEvent(QPaintEvent *);
};
#endif // WIDGET_H

• 實現(xiàn)文件代碼如下:

#include "widget.h"
#include "ui_widget.h"Widget::Widget(QWidget *parent) :QWidget(parent),ui(new Ui::Widget)
{ui->setupUi(this);resize(600,560);setMouseTracking(true);m_nRotationAngle = 0;m_i = 0;m_T = 0;isDefault = false;m_btn = new QPushButton(this);m_btn->move(273,450);m_labTr = new QLabel(tr("抽獎結(jié)果:"),this);m_labTr->move(223,105);m_ldeRe = new QLineEdit(tr("未開始抽獎"),this);m_ldeRe->move(293,103);m_ldeRe->setEnabled(false);m_ldeRe->setAlignment(Qt::AlignCenter);m_btn->setText(tr("啟動"));m_timer = new QTimer(this);setStyleSheet("QLabel{""font-size:15px;""""}""QLineEdit{""color:white;""font-size:14px;""background-color:#f57ab8;""border:1px solid gray;""border-radius:5px;""}""QPushButton{""width:36px;""height:16px;""text-align:center;""background-color:#da0000;""color:white;""border:1px solid gray;""border-radius:3px;""}");connect(m_timer,SIGNAL(timeout()),this,SLOT(updatePaint()));connect(m_btn,SIGNAL(clicked(bool)),this,SLOT(btnClicked()));connect(this,SIGNAL(sigResult(int)),this,SLOT(reResult(int)));
}Widget::~Widget()
{delete ui;
}void Widget::gradientArc(QPainter *painter, int radius, int startAngle,int angleLength, int arcHeight, QRgb color)
{QRadialGradient gradient(0,0,radius);gradient.setColorAt(0,Qt::black);gradient.setColorAt(1.0,color);painter->setBrush(gradient);// << 1（左移1位）相當(dāng)于radius*2 即：150*2=300//QRectF(-150, -150, 300, 300)QRectF rectf(-radius,-radius,radius << 1,radius << 1);QPainterPath path;path.arcTo(rectf,startAngle,angleLength);QPainterPath subPath;subPath.addEllipse(rectf.adjusted(arcHeight, arcHeight, -arcHeight, -arcHeight));//subPath.addEllipse(rect.adjusted(arcHeight,arcHeight,-arcHeight,-arcHeight));//path為扇形 subPath為橢圓path -= subPath;////        QFont font;//        font.setFamily("Microsoft YaHei");//        font.setPointSize(14);//        painter->setPen(Qt::NoPen);//        path.addText(path.pointAtPercent(0.5), font, QStringLiteral("一去丶二三里"));painter->setPen(Qt::NoPen);painter->drawPath(path);
}void Widget::updatePaint()
{if(!isDefault){m_nRotationAngle = m_nRotationAngle + 33;if(m_nRotationAngle >360){m_nRotationAngle = 0;m_T++;if(m_T == 3){m_nRotationAngle = m_nRotationAngle + 5;}else if(m_T == 5){stopInit();}}}else{m_nRotationAngle = m_nRotationAngle + 33;if(m_nRotationAngle >360){m_nRotationAngle = 0;m_T++;if(m_T == 3){m_nRotationAngle = m_nRotationAngle + 5;}else if(m_T == 5){stopInit();}}}update();
}void Widget::btnClicked()
{if(!m_timer->isActive()){m_timer->start(30);int iRangd = getRand();emit sigResult(iRangd);m_T = 0;m_ldeRe->setStyleSheet("color:white;");m_ldeRe->setText(tr("正在抽獎..."));}else{stopInit();}
}void Widget::reResult(int re)
{isDefault = true;m_map =  returnResult(re);QMapIterator<int,QString> ii(m_map);if(m_map.isEmpty())return;while(ii.hasNext()){ii.next();m_Re = ii.value();m_nRo = ii.key();}
}void Widget::stopRotate()
{m_timer->stop();
}QMap<int,QString> Widget::returnResult(int re)
{int ire = 0;QMap<int,QString> map;switch(re){case 0://（rand（）%（b-a））+ a，-->[a,b)的隨機數(shù)ire = (qrand() % (45 - 0) + 0);qDebug() << "二等獎";map.insert(ire,tr("二等獎"));break;case 1:qDebug() << "謝謝1";ire = (qrand() % (90 - 46) + 46);map.insert(ire,tr("謝謝參與"));break;case 2:qDebug() << "特等獎";ire = (qrand() % (135 - 90) + 90);map.insert(ire,tr("特等獎"));break;case 3:qDebug() << "三等獎";ire = (qrand() % (180 - 135) + 135);map.insert(ire,tr("三等獎"));break;case 4:qDebug() << "幸運2";ire = (qrand() % (225 - 180) + 180);map.insert(ire,tr("幸運獎"));break;case 5:qDebug() << "謝謝2";ire = (qrand() % (270 - 225) + 225);map.insert(ire,tr("謝謝參與"));break;case 6:qDebug() << "一等獎";ire = (qrand() % (315 - 270) + 270);map.insert(ire,tr("一等獎"));break;case 7:qDebug() << "幸運1";ire = (qrand() % (360 - 315) + 315);map.insert(ire,tr("幸運獎"));break;default:break;}return map;
}QString Widget::showAwards(Widget::Awards award)
{QString result = "";switch(award){case Spe:result = "特等獎";break;case First:result = "一等獎";break;case Second:result = "二等獎";break;case Third:result = "三等獎";break;case Luck_Fir:result = "幸運獎";break;case Luck_Sec:result = "幸運獎";break;case ThanK_Fir:result = "謝謝參與";break;case Thank_Sec:result = "謝謝參與";break;default:break;}return result;
}void Widget::stopInit()
{m_timer->stop();m_T = 0;isDefault = false;int ip =  m_nRo;int tp = m_nRotationAngle;if(ip > m_nRotationAngle){for (int i = tp; i <= ip; i++){m_nRotationAngle = i;}}m_nRotationAngle = m_nRo;m_ldeRe->setText(m_Re);update();
}//設(shè)置獎項概率
int Widget::getRand()
{int re = 10;QTime tim = QTime::currentTime();qsrand(tim.msec() + tim.second()*1000);int rand = ((qrand() % 100) + 1);qDebug() << "rand:" << rand;if(rand == 1){re = 2;}else if((rand <= 4) && (rand >= 2 )){re = 6;}else if((rand <= 9) && (rand >= 5 )){re = 0;}else if((rand <= 20) && (rand >= 10 )){re = 3;}else if((rand <= 35) && (rand >= 21 )){re = 4;}else if((rand <= 50) && (rand >= 36 )){re = 7;}else if((rand <= 75) && (rand >= 51 )){re = 1;}else if((rand <= 100) && (rand >= 76 )){re = 5;}return re;
}void Widget::paintEvent(QPaintEvent *)
{QPainter painter(this);painter.setRenderHint(QPainter::Antialiasing,true);int radius = 150;int arcHeight = 138;//>>1 右移一位，相當(dāng)于width() / 2painter.translate(width() >> 1,height() >> 1);//    painter.rotate(m_nRotationAngle);/** 參數(shù)二：半徑* 參數(shù)三：開始的角度* 參數(shù)四：指掃取的角度-順時針（360度 / 8 = 45度）* 參數(shù)五：圓環(huán)的高度* 參數(shù)六：填充色**/gradientArc(&painter,radius,0,45,arcHeight,qRgb(200,200,0));gradientArc(&painter,radius,45,45,arcHeight,qRgb(200,0,200));gradientArc(&painter,radius,90,45,arcHeight,qRgb(0,200,200));gradientArc(&painter,radius,135,45,arcHeight,qRgb(200,0,0));gradientArc(&painter,radius,225,45,arcHeight,qRgb(0,200,0));gradientArc(&painter,radius,180,45,arcHeight,qRgb(0,0,200));gradientArc(&painter,radius,270,45,arcHeight,qRgb(0,0,0));gradientArc(&painter,radius,315,45,arcHeight,qRgb(150,150,150));painter.setPen(QPen(QColor(Qt::yellow),2));painter.rotate(-35);painter.drawText(60,30,tr("謝謝參與"));painter.rotate(40);painter.drawText(70,30,tr("一等獎"));painter.rotate(95);painter.drawText(70,30,tr("二等獎"));painter.rotate(135);painter.drawText(70,30,tr("三等獎"));painter.rotate(180);painter.drawText(70,30,tr("幸運獎"));painter.rotate(210);painter.drawText(70,30,tr("幸運獎"));painter.rotate(245);painter.drawText(70,30,tr("謝謝參與"));painter.rotate(40);painter.drawText(70,30,tr("特等獎"));QPainter painter2(this);painter2.setRenderHint(QPainter::Antialiasing,true);painter2.translate(width() >> 1,height() >> 1);painter2.rotate(m_nRotationAngle);static const QPoint poit[4] = {QPoint(0,-18),QPoint(10,0),QPoint(0,60),QPoint(-10,0)};painter2.setBrush(QColor(Qt::red));painter2.setPen(Qt::NoPen);painter2.drawPolygon(poit,4);painter2.setBrush(QColor(Qt::yellow));painter2.drawEllipse(-7,-7,14,14);
}

• 我自己寫的代碼比較爛，各位看官嘴下留情…一直想實現(xiàn)的緩動效果，就是當(dāng)針快要停下的時候緩慢的停下來。說是需要添加額外的庫。水平有限，以后有機會再慢慢實現(xiàn)。