Qt之模型/视图（自定义按钮）

简述

衍伸前面的章节，我们对QTableView实现了数据显示、自定义排序、显示复选框、进度条等功能的实现，本节主要针对自定义按钮进行讲解，这节过后，也希望大家对自定义有更深入的了解，在以后的功能开发过程中，相信无论遇到什么样式形式，我们都可以很好地实现。

• 简述
• 效果
• QStyledItemDelegate
  • 源码
• 衍伸

效果

QStyledItemDelegate

源码

.h

包含显示按钮需要用到的智能指针，按钮的宽度、高度、按钮之间的间距、鼠标的坐标等。

class TableViewDelegate: public QStyledItemDelegate
{
    Q_OBJECT

public:
    explicit TableViewDelegate(QWidget *parent = 0);
    ~TableViewDelegate();
    void paint(QPainter *painter, const QStyleOptionViewItem &option, const QModelIndex &index) const;
    bool editorEvent(QEvent* event, QAbstractItemModel* model, const QStyleOptionViewItem& option, const QModelIndex& index);

signals:
    void open(const QModelIndex &index);
    void deleteData(const QModelIndex &index);

private:
    QPoint m_mousePoint;  // 鼠标位置
    QScopedPointer<QPushButton> m_pOpenButton;
    QScopedPointer<QPushButton> m_pDeleteButton;
    QStringList m_list;
    int m_nSpacing;  // 按钮之间的间距
    int m_nWidth;  // 按钮宽度
    int m_nHeight;  // 按钮高度
    int m_nType;  // 按钮状态-1：划过 2：按下
};

.cpp

主要设置按钮样式，实现鼠标划过、按下，响应鼠标事件等操作。

TableViewDelegate::TableViewDelegate(QWidget *parent)
    : QStyledItemDelegate(parent),
      m_pOpenButton(new QPushButton()),
      m_pDeleteButton(new QPushButton()),
      m_nSpacing(5),
      m_nWidth(25),
      m_nHeight(20)
{
    // 设置按钮正常、划过、按下样式
    m_pOpenButton->setStyleSheet("QPushButton {border: none; background-color: transparent; image:url(:/Images/open);} 
                                 QPushButton:hover {image:url(:/Images/openHover);} 
                                 QPushButton:pressed {image:url(:/Images/openPressed);}");

    m_pDeleteButton->setStyleSheet("QPushButton {border: none; background-color: transparent; image:url(:/Images/delete);} 
                                 QPushButton:hover {image:url(:/Images/deleteHover);} 
                                 QPushButton:pressed {image:url(:/Images/deletePressed);}");
    m_list << QStringLiteral("打开") << QStringLiteral("删除");
}

TableViewDelegate::~TableViewDelegate()
{

}

// 绘制按钮
void TableViewDelegate::paint(QPainter *painter, const QStyleOptionViewItem &option, const QModelIndex &index) const
{
    QStyleOptionViewItem viewOption(option);
    initStyleOption(&viewOption, index);
    if (option.state.testFlag(QStyle::State_HasFocus))
        viewOption.state = viewOption.state ^ QStyle::State_HasFocus;

    QStyledItemDelegate::paint(painter, viewOption, index);

    if (index.column() == FILE_OPERATE_COLUMN)
    {
        // 计算按钮显示区域
        int nCount = m_list.count();
        int nHalf = (option.rect.width() - m_nWidth * nCount - m_nSpacing * (nCount - 1)) / 2;
        int nTop = (option.rect.height() - m_nHeight) / 2;

        for (int i = 0; i < nCount; ++i)
        {
            // 绘制按钮
            QStyleOptionButton button;
            button.rect = QRect(option.rect.left() + nHalf + m_nWidth * i + m_nSpacing * i,
                                option.rect.top() + nTop,  m_nWidth, m_nHeight);
            button.state |= QStyle::State_Enabled;
            //button.iconSize = QSize(16, 16);
            //button.icon = QIcon(QString(":/Images/%1").arg(m_list.at(i)));

            if (button.rect.contains(m_mousePoint))
            {
                if (m_nType == 0)
                {
                    button.state |= QStyle::State_MouseOver;
                    //button.icon = QIcon(QString(":/Images/%1Hover").arg(m_list.at(i)));
                }
                else if (m_nType == 1)
                {
                    button.state |= QStyle::State_Sunken;
                    //button.icon = QIcon(QString(":/Images/%1Pressed").arg(m_list.at(i)));
                }
            }

            QWidget *pWidget = (i == 0) ? m_pOpenButton.data() : m_pDeleteButton.data();
            QApplication::style()->drawControl(QStyle::CE_PushButton, &button, painter, pWidget);
        }
    }
}

// 响应按钮事件 - 划过、按下
bool TableViewDelegate::editorEvent(QEvent* event, QAbstractItemModel* model, const QStyleOptionViewItem& option, const QModelIndex& index)
{
    if (index.column() != FILE_OPERATE_COLUMN)
        return false;

    m_nType = -1;
    bool bRepaint = false;
    QMouseEvent *pEvent = static_cast<QMouseEvent *> (event);
    m_mousePoint = pEvent->pos();

    int nCount = m_list.count();
    int nHalf = (option.rect.width() - m_nWidth * nCount - m_nSpacing * (nCount - 1)) / 2;
    int nTop = (option.rect.height() - m_nHeight) / 2;

    // 还原鼠标样式
    QApplication::restoreOverrideCursor();

    for (int i = 0; i < nCount; ++i)
    {
        QStyleOptionButton button;
        button.rect = QRect(option.rect.left() + nHalf + m_nWidth * i + m_nSpacing * i,
                            option.rect.top() + nTop,  m_nWidth, m_nHeight);

        // 鼠标位于按钮之上
        if (!button.rect.contains(m_mousePoint))
            continue;

        bRepaint = true;
        switch (event->type())
        {
        // 鼠标滑过
        case QEvent::MouseMove:
        {
            // 设置鼠标样式为手型
            QApplication::setOverrideCursor(Qt::PointingHandCursor);

            m_nType = 0;
            QToolTip::showText(pEvent->globalPos(), m_list.at(i));
            break;
        }
        // 鼠标按下
        case QEvent::MouseButtonPress:
        {
            m_nType = 1;
            break;
        }
        // 鼠标释放
        case QEvent::MouseButtonRelease:
        {
            if (i == 0)
            {
                emit open(index);
            }
            else
            {
                emit deleteData(index);
            }
            break;
        }
        default:
            break;
        }
    }

    return bRepaint;
}

衍伸

通过上面的实现，我们可以自定义按钮的样式、文本、显示区域、等，我们也可以通过QStyleOptionButton的icon和iconSize来设置按钮的图标与图标大小，通过响应按钮来实现我们自己的事件。