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.youkuaiyun.com/caoshangpa/article/details/51036267

        CMySplashScreen类的实现如下所示

1. #ifndef CMYSPLASHSCREEN_H
2. #define CMYSPLASHSCREEN_H
4. #include <QSplashScreen>
5. #include <QPixmap>
6. #include <QProgressBar>
7. #include <QList>
8. #include <QtGlobal>
10. class CMySplashScreen: public QSplashScreen
11. {
12. Q_OBJECT
14. public:
15. CMySplashScreen(QPixmap& pixmap,int time);
16. ~CMySplashScreen();
18. private:
19. //进度条
20. QProgressBar *ProgressBar;
21. //随机数列表
22. QList<int> numbersList;
23. //启动界面停留的时间
24. int elapseTime;
26. private:
27. void setProgress();
28. void generateAscendRandomNumber();
30. private slots:
31. void slotUpdateProgress();
32. };
34. #endif // CMYSPLASHSCREEN_H

1. #include "cmysplashscreen.h"
2. #include <QTime>
3. #include <QTimer>
4. CMySplashScreen::CMySplashScreen(QPixmap& pixmap,int time) :
5. QSplashScreen(pixmap),
6. elapseTime(time)
7. {
8. ProgressBar = new QProgressBar(this);
9. //设置进度条的位置
10. ProgressBar->setGeometry(0,pixmap.height()-50,pixmap.width(),30);
11. //设置进度条的样式
12. ProgressBar->setStyleSheet("QProgressBar {color:black;font:30px;text-align:center; }QProgressBar::chunk {background-color: rgb(202, 165, 14);}");
13. //设置进度条的范围
14. ProgressBar->setRange(0, 100);
15. //设置进度条的当前进度
16. ProgressBar->setValue(0);
18. generateAscendRandomNumber();
19. setProgress();
20. }
22. CMySplashScreen::~CMySplashScreen()
23. {
25. }
27. void CMySplashScreen::setProgress()
28. {
29. int tempTime=elapseTime/100;
30. for(int i=0;i<100;i++)
31. {
32. QTimer::singleShot(i*tempTime, this, SLOT(slotUpdateProgress()));
33. }
34. QTimer::singleShot(elapseTime, this, SLOT(close()));
35. }
37. void CMySplashScreen::slotUpdateProgress()
38. {
39. static int num=0;
40. ProgressBar->setValue(numbersList[num]);
41. num++;
42. }
44. void CMySplashScreen::generateAscendRandomNumber()
45. {
46. int i;
47. qsrand(QTime(0,0,0).secsTo(QTime::currentTime()));
48. //生成100个大小在[0,100]之间的随机数
49. for(i=0;i<100;i++)
50. {
51. numbersList.append(qrand()%101);
52. }
53. //递增排序
54. qSort(numbersList.begin(),numbersList.end());
55. }
56. 启动界面效果如下所示。
57.