QScrollArea可以帮助我们实现让一个widget的内容带有滚动条（QWidget里内置QScrollArea，QScrollArea里再内置其它QWidget）

使用QScrollArea可以帮助我们实现让一个widget的内容带有滚动条，用户可以通过拖动滚动条来查看更多内容， 
代码示例如下： 

1.带有滚动条的widget列表

1. #include "widget.h"
2. Widget::Widget(QWidget *parent)
3. : QWidget(parent)
4. {
5. list=new QListWidget();
6. lay=new QHBoxLayout();
7. QSizeGrip *gr=new QSizeGrip(list);//用来重设widget的size
8. scroll=new QScrollArea();
9. scroll->setWidget(list);
10. scroll->setAlignment(Qt::AlignLeft);
11. // scroll->setWidgetResizable(true);
12. scroll->setBackgroundRole(QPalette::Dark);// 设置滚动区域的背景
13. //win=new QWidget();
14. item1=new QListWidgetItem("BlueHills",list);//向widget列表中加入一项
15. item2=new QListWidgetItem("Sunset",list);
16. item3=new QListWidgetItem("Water lilies",list);
17. item4=new QListWidgetItem("Himaliya is a good place",list);
18. item5=new QListWidgetItem("Ooty",list);
19. item6=new QListWidgetItem("Hero Honda",list);
20. item7=new QListWidgetItem("www.google.com",list);
21. item8=new QListWidgetItem("orkut.com",list);
22. item9=new QListWidgetItem("sunrise",list);
23. item10=new QListWidgetItem("OVI",list);
24. item11=new QListWidgetItem("Nokia N97",list);
25. item12=new QListWidgetItem("forum.nokia.com",list);
26. item13=new QListWidgetItem("wellcome to Qt",list);
27. item14=new QListWidgetItem("Qt rocks for s60",list);
28. item15=new QListWidgetItem("Symbian c++",list);
29. item16=new QListWidgetItem("5800 Xpress Music",list);
30. item17=new QListWidgetItem("My best Phone",list);
31. item18=new QListWidgetItem("I like N97",list);
32. item19=new QListWidgetItem("Go for 5800",list);
33. item20=new QListWidgetItem("America",list);
34. // lay->addWidget(list);
35. lay->addWidget(scroll);
36. setLayout(lay);//setting layout
37. showMaximized();
38. }
39. Widget::~Widget()
40. {
41. }

2.带有滚动条的图片显示

1. Widget::Widget(QWidget *parent)
2. : QWidget(parent)
3. {
4. QLabel *imageLabel = new QLabel(this);
5. QImage image("E:\\flower.png",this);
6. lay=new QHBoxLayout(this);
7. imageLabel->setPixmap(QPixmap::fromImage(image));
8. scrollArea = new QScrollArea(this);
9. scrollArea->setWidgetResizable(1);
10. scrollArea->setBackgroundRole(QPalette::Dark);
11. scrollArea->setWidget(imageLabel);
12. lay->addWidget(scrollArea);
13. setLayout(lay);
14. }
15. Widget::~Widget()
16. {
17. }

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