简述

前面分享了QTableView中如何添加复选框。本节主要介绍QTableView中的表头-QHeaderView添加复选框的功能，下面以水平表头为例，垂直表头类似！

效果

QHeaderView

源码

TableHeaderView::TableHeaderView(Qt::Orientation orientation, QWidget *parent)

    : QHeaderView(orientation, parent),

      m_bPressed(false),

      m_bChecked(false),

      m_bTristate(false),

      m_bNoChange(false),

      m_bMoving(false)

{

    // setStretchLastSection(true);

    setHighlightSections(false);

    setMouseTracking(true);

    // 响应鼠标

    setSectionsClickable(true);

}

// 槽函数，用于更新复选框状态

void TableHeaderView::onStateChanged(int state)

{

    if (state == Qt::PartiallyChecked) {

        m_bTristate = true;

        m_bNoChange = true;

    } else {

        m_bNoChange = false;

    }

    m_bChecked = (state != Qt::Unchecked);

    update();

}

// 绘制复选框

void TableHeaderView::paintSection(QPainter *painter, const QRect &rect, int logicalIndex) const

{

    painter->save();

    QHeaderView::paintSection(painter, rect, logicalIndex);

    painter->restore();

    if (logicalIndex == CHECK_BOX_COLUMN)

    {

        QStyleOptionButton option;

        option.initFrom(this);

        if (m_bChecked)

            option.state |= QStyle::State_Sunken;

        if (m_bTristate && m_bNoChange)

            option.state |= QStyle::State_NoChange;

        else

            option.state |= m_bChecked ? QStyle::State_On : QStyle::State_Off;

        if (testAttribute(Qt::WA_Hover) && underMouse()) {

            if (m_bMoving)

                option.state |= QStyle::State_MouseOver;

            else

                option.state &= ~QStyle::State_MouseOver;

        }

        QCheckBox checkBox;

        option.iconSize = QSize(20, 20);

        option.rect = rect;

        style()->drawPrimitive(QStyle::PE_IndicatorCheckBox, &option, painter, &checkBox);

        //style()->drawItemPixmap(painter, rect, Qt::AlignCenter, QPixmap(":/images/checkBoxChecked"));

        //style()->drawControl(QStyle::CE_CheckBox, &option, painter, this);

    }

}

// 鼠标按下表头

void TableHeaderView::mousePressEvent(QMouseEvent *event)

{

    int nColumn = logicalIndexAt(event->pos());

    if ((event->buttons() & Qt::LeftButton) && (nColumn == CHECK_BOX_COLUMN))

    {

        m_bPressed = true;

    }

    else

    {

        QHeaderView::mousePressEvent(event);

    }

}

// 鼠标从表头释放，发送信号，更新model数据

void TableHeaderView::mouseReleaseEvent(QMouseEvent *event)

{

    if (m_bPressed)

    {

        if (m_bTristate && m_bNoChange)

        {

            m_bChecked = true;

            m_bNoChange = false;

        }

        else

        {

            m_bChecked = !m_bChecked;

        }

        update();

        Qt::CheckState state = m_bChecked ? Qt::Checked : Qt::Unchecked;

        emit stateChanged(state);

    }

    else

    {

        QHeaderView::mouseReleaseEvent(event);

    }

    m_bPressed = false;

}

// 鼠标滑过、离开，更新复选框状态

bool TableHeaderView::event(QEvent *event)

{

    if (event->type() == QEvent::Enter || event->type() == QEvent::Leave)

    {

        QMouseEvent *pEvent = static_cast<QMouseEvent *>(event);

        int nColumn = logicalIndexAt(pEvent->x());

        if (nColumn == CHECK_BOX_COLUMN)

        {

            m_bMoving = (event->type() == QEvent::Enter);

            update();

            return true;

        }

    }

    return QHeaderView::event(event);

}

接口说明

• onStateChanged
  
  槽函数，与model关联，当model的数据发生变化时，表头复选中状态也随之变化。

• paintSection
  
  绘制部分，主要用于绘制复选框，主要设置QStyleOptionButton的状态，然后通过QStyle的drawPrimitive绘制样式。

• mousePressEvent
  
  鼠标按下表头，设置被按下的标志为true。

• mouseReleaseEvent
  
  鼠标从表头释放，发送信号，更新model数据。

• event
  
  鼠标滑过、离开，更新复选框状态。

QAbstractTableModel

源码

源码过多，这里只贴更改部分及新增部分，其它部分请参考：Qt之QTableView添加复选框（QAbstractItemDelegate）

// 设置表格项数据

bool TableModel::setData(const QModelIndex &index, const QVariant &value, int role)

{

    if (!index.isValid())

        return false;

    int nColumn = index.column();

    FileRecord record = m_recordList.at(index.row());

    switch (role)

    {

    case Qt::DisplayRole:

    {

        if (nColumn == File_PATH_COLUMN)

        {

            record.strFilePath = value.toString();

            m_recordList.replace(index.row(), record);

            emit dataChanged(index, index);

            return true;

        }

    }

    case Qt::CheckStateRole:

    case Qt::UserRole:

    {

        if (nColumn == CHECK_BOX_COLUMN)

        {

            record.bChecked = value.toBool();

            m_recordList.replace(index.row(), record);

            emit dataChanged(index, index);

            if (role == Qt::UserRole)

                onStateChanged();

            return true;

        }

    }

    default:

        return false;

    }

    return false;

}

// 复选状态改变，通知表头更新复选状态

void TableModel::onStateChanged()

{

    Qt::CheckState state = Qt::Unchecked;

    int nCount = m_recordList.count();

    int nSelectedCount = 0;

    FileRecord record;

    for (int i = 0; i < nCount; ++i)

    {

        record = m_recordList.at(i);

        if (record.bChecked)

            ++nSelectedCount;

    }

    if (nSelectedCount >= nCount)

    {

        state = Qt::Checked;

    }

    else if (nSelectedCount > 0)

    {

        state = Qt::PartiallyChecked;

    }

    emit stateChanged(state);

}

// 接收表头复选状态更新变化，修改表格复选状态

void TableModel::onStateChanged(int state)

{

    QModelIndex index;

    for (int i = 0; i < rowCount(); ++i)

    {

        index = this->index(i, CHECK_BOX_COLUMN);

        setData(index, state == Qt::Checked, Qt::CheckStateRole);

    }

}

接口说明

• setData
  
  设置表格项数据，关键代码：当role为Qt::UserRole时候，会调用onStateChanged()函数，来更新表头！

• onStateChanged
  
  复选状态改变，通知表头更新复选状态。

• onStateChanged(int state)
  
  槽函数，接收表头复选状态更新变化，修改表格复选状态。

使用

这时，就需要将header与model的信号与槽关联起来，更新复选框状态了！

QTableView *pTableView = new QTableView(this);

TableModel *pModel = new TableModel(this);

TableHeaderView *pHeader = new TableHeaderView(Qt::Horizontal, this);

CheckBoxDelegate *pDelegate = new CheckBoxDelegate(this);

pTableView->setHorizontalHeader(pHeader);

pTableView->setModel(pModel);

pTableView->setItemDelegate(pDelegate);

connect(pModel, SIGNAL(stateChanged(int)), pHeader, SLOT(onStateChanged(int)));

connect(pHeader, SIGNAL(stateChanged(int)), pModel, SLOT(onStateChanged(int)));