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"
4. Widget::Widget(QWidget *parent)
5.     : QWidget(parent)
6. {
7.     list=new QListWidget();
8.     lay=new QHBoxLayout();
9.    QSizeGrip *gr=new QSizeGrip(list);//用来重设widget的size
10.     scroll=new QScrollArea();
12.     scroll->setWidget(list);
13.     scroll->setAlignment(Qt::AlignLeft);
14.    // scroll->setWidgetResizable(true);
15.     scroll->setBackgroundRole(QPalette::Dark);// 设置滚动区域的背景
16.     //win=new QWidget();
17.    item1=new QListWidgetItem("BlueHills",list);//向widget列表中加入一项
18.    item2=new QListWidgetItem("Sunset",list);
19.    item3=new QListWidgetItem("Water lilies",list);
20.    item4=new QListWidgetItem("Himaliya is a good place",list);
21.    item5=new QListWidgetItem("Ooty",list);
22.    item6=new QListWidgetItem("Hero Honda",list);
23.    item7=new QListWidgetItem("www.google.com",list);
24.    item8=new QListWidgetItem("orkut.com",list);
25.    item9=new QListWidgetItem("sunrise",list);
26.    item10=new QListWidgetItem("OVI",list);
27.    item11=new QListWidgetItem("Nokia N97",list);
28.    item12=new QListWidgetItem("forum.nokia.com",list);
29.    item13=new QListWidgetItem("wellcome to Qt",list);
30.    item14=new QListWidgetItem("Qt rocks for s60",list);
31.    item15=new QListWidgetItem("Symbian c++",list);
32.    item16=new QListWidgetItem("5800 Xpress Music",list);
33.    item17=new QListWidgetItem("My best Phone",list);
34.    item18=new QListWidgetItem("I like N97",list);
35.    item19=new QListWidgetItem("Go for 5800",list);
36.    item20=new QListWidgetItem("America",list);
37. // lay->addWidget(list);
38.    lay->addWidget(scroll);
40.    setLayout(lay);//setting layout
41.    showMaximized();
44. }
46. Widget::~Widget()
47. {
49. }

 
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));
9. scrollArea = new QScrollArea(this);
10. scrollArea->setWidgetResizable(1);
11. scrollArea->setBackgroundRole(QPalette::Dark);
12. scrollArea->setWidget(imageLabel);
13. lay->addWidget(scrollArea);
14. setLayout(lay);
15. }
17. Widget::~Widget()
18. {
20. }

http://blog.chinaunix.net/uid-25749806-id-337219.html

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）