因为此前有个项目做的软件要在平板上运行，屏幕不大，滚动条太细，如果加粗滚动条影响美观，滚动条太细又点不到，用户体验较差。所以做了这个鼠标拖动即可代替鼠标滚轮的功能。

dialogex.h

#ifndef DIALOGEX_H
#define DIALOGEX_H#include <QDialog>
#include <QScrollArea>
#include <QScrollBar>
#include <QLabel>
#include <QMouseEvent>class DialogEx : public QDialog
{Q_OBJECTpublic:DialogEx(QWidget *parent = 0);~DialogEx();void init();QScrollArea*    m_pScrollArea;QWidget*        m_pScrollWidget;QLabel*         m_pTipLabel;bool            m_bMousePressed;QPoint          m_PressPosition;protected:void mouseMoveEvent(QMouseEvent *e) Q_DECL_OVERRIDE;void mousePressEvent(QMouseEvent *e) Q_DECL_OVERRIDE;void mouseReleaseEvent(QMouseEvent *e) Q_DECL_OVERRIDE;
};#endif // DIALOGEX_H

dialogex.cpp

#include "dialogex.h"DialogEx::DialogEx(QWidget *parent): QDialog(parent), m_pScrollArea(NULL), m_pScrollWidget(NULL), m_pTipLabel(NULL), m_bMousePressed(false)
{init();
}DialogEx::~DialogEx()
{}void DialogEx::init()
{this->setFixedSize(300, 200);m_pScrollArea = new QScrollArea(this);m_pScrollWidget = new QWidget(m_pScrollArea);m_pTipLabel = new QLabel("证明我移动了", m_pScrollWidget);m_pScrollArea->setFixedSize(this->width(), this->height());m_pScrollWidget->setFixedSize(this->width(), this->height() * 2);m_pTipLabel->adjustSize();m_pScrollArea->setWidget(m_pScrollWidget);m_pScrollArea->setAlignment(Qt::AlignCenter);m_pScrollArea->setHorizontalScrollBarPolicy(Qt::ScrollBarAlwaysOff);m_pScrollArea->move(0, 0);m_pScrollWidget->move(0, 0);m_pTipLabel->move(100, 100);
}void DialogEx::mouseMoveEvent(QMouseEvent *e)
{if (!m_bMousePressed){return;}QPoint currentPt = e->pos();int dist = m_PressPosition.y() - currentPt.y();m_pScrollArea->verticalScrollBar()->setValue(m_pScrollArea->verticalScrollBar()->value() + dist);m_PressPosition = currentPt;
}void DialogEx::mousePressEvent(QMouseEvent *e)
{m_bMousePressed = true;m_PressPosition = e->pos();
}void DialogEx::mouseReleaseEvent(QMouseEvent *e)
{Q_UNUSED(e);m_bMousePressed = false;m_PressPosition.setX(0);m_PressPosition.setY(0);
}

main.cpp

#include "dialogex.h"
#include <QApplication>int main(int argc, char *argv[])
{QApplication a(argc, argv);DialogEx w;w.show();return a.exec();
}

例子中只做了竖直方向的拖动，水平方向同理