QScrollArea 用法

#include <QScrollArea>
#include <QPushButton>
MainWindow::MainWindow(QWidget *parent) :
    QMainWindow(parent),
    ui(new Ui::MainWindow)
{
    ui->setupUi(this);
    QScrollArea * scrollArea = new QScrollArea(this);
    QWidget * pWgt = new QWidget;

    QVBoxLayout *pLayout = new QVBoxLayout();//網格布局
    for(int i = 0; i < 100; i++)
    {
        QPushButton *pBtn = new QPushButton();
        pBtn->setText(QString("按鈕%1").arg(i));
        pBtn->setMinimumSize(QSize(60,30));   //width height
        pLayout->addWidget(pBtn);//把按鈕添加到布局控件中
    }
    pWgt->setLayout(pLayout);

      //這一句setWidget必須放在pWgt里面的內容都准備完畢之后，否則顯示有問題
      scrollArea->setWidget(pWgt);
      setCentralWidget(scrollArea);

}