Qt带进度条的启动界面

       通过继承QSplashScreen类，得到CMySplashScreen类，然后在CMySplashScreen中定义QProgressBar变量，该变量以CMySplashScreen为父类，这样就实现了带进度条的启动界面。

        进度条加入后，需要控制进度条的值，为了让进度条看起来更逼真，可以通过生成随机数的方式，把随机数当做进度条的值。此时，生成的随机数必须是从小到大排列的，要不然进度条就不会从开端一步步走到终点，而是会出现走到一半后又回到开端等反常现象。如何生成随机数可参考http://blog.csdn.net/caoshangpa/article/details/51036267

        CMySplashScreen类的实现如下所示

#ifndef CMYSPLASHSCREEN_H
#define CMYSPLASHSCREEN_H

#include <QSplashScreen>
#include <QPixmap>
#include <QProgressBar>
#include <QList>
#include <QtGlobal>

class CMySplashScreen: public QSplashScreen
{
Q_OBJECT

public:
CMySplashScreen(QPixmap& pixmap, int time);
~CMySplashScreen();

private:
//进度条
QProgressBar *ProgressBar;
//随机数列表
QList< int> numbersList;
//启动界面停留的时间
int elapseTime;

private:
void setProgress();
void generateAscendRandomNumber();

private slots:
void slotUpdateProgress();
};

#endif // CMYSPLASHSCREEN_H

#include "cmysplashscreen.h"
#include <QTime>
#include <QTimer>
CMySplashScreen::CMySplashScreen(QPixmap& pixmap, int time) :
QSplashScreen(pixmap),
elapseTime(time)
{
ProgressBar = new QProgressBar( this);
//设置进度条的位置
ProgressBar->setGeometry( 0,pixmap.height() -50,pixmap.width(), 30);
//设置进度条的样式
ProgressBar->setStyleSheet( "QProgressBar {color:black;font:30px;text-align:center; }QProgressBar::chunk {background-color: rgb(202, 165, 14);}");
//设置进度条的范围
ProgressBar->setRange( 0, 100);
//设置进度条的当前进度
ProgressBar->setValue( 0);

generateAscendRandomNumber();
setProgress();
}

CMySplashScreen::~CMySplashScreen()
{

}

void CMySplashScreen::setProgress()
{
int tempTime=elapseTime/ 100;
for( int i= 0;i< 100;i++)
{
QTimer::singleShot(i*tempTime, this, SLOT(slotUpdateProgress()));
}
QTimer::singleShot(elapseTime, this, SLOT(close()));
}

void CMySplashScreen::slotUpdateProgress()
{
static int num= 0;
ProgressBar->setValue(numbersList[num]);
num++;
}

void CMySplashScreen::generateAscendRandomNumber()
{
int i;
qsrand(QTime( 0, 0, 0).secsTo(QTime::currentTime()));
//生成100个大小在[0,100]之间的随机数
for(i= 0;i< 100;i++)
{
numbersList.append(qrand()% 101);
}
//递增排序
qSort(numbersList.begin(),numbersList.end());
}