Qt之QHeaderView加入復選框

簡述

前面分享了QTableView中怎樣加入復選框。

本節主要介紹QTableView中的表頭-QHeaderView加入復選框的功能，以下以水平表頭為例。垂直表頭相似！

• 簡述
• 效果
• QHeaderView
  • 源代碼
  • 接口說明
• QAbstractTableModel
  • 源代碼
  • 接口說明
• 使用

效果

QHeaderView

源代碼

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);

    // 響應鼠標
    setSectionsClickable(true);
}

// 槽函數，用於更新復選框狀態
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();
}

// 繪制復選框
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); } } // 鼠標按下表頭 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); } } // 鼠標從表頭釋放。發送信號，更新model數據 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; } // 鼠標滑過、離開，更新復選框狀態 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); } 

接口說明

• onStateChanged
  槽函數，與model關聯。當model的數據發生變化時，表頭復選中狀態也隨之變化。

• paintSection
  繪制部分，主要用於繪制復選框，主要設置QStyleOptionButton的狀態。然后通過QStyle的drawPrimitive繪制樣式。

• mousePressEvent
  鼠標按下表頭，設置被按下的標志為true。

• mouseReleaseEvent
  鼠標從表頭釋放。發送信號，更新model數據。

• event
  鼠標滑過、離開。更新復選框狀態。

QAbstractTableModel

源代碼

源代碼過多，這里僅僅貼更改部分及新增部分，其他部分請參考：Qt之QTableView加入復選框（QAbstractItemDelegate）

// 設置表格項數據
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;
}

// 復選狀態改變，通知表頭更新復選狀態
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);
}

// 接收表頭復選狀態更新變化。改動表格復選狀態
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);
    }
}

接口說明

• setData
  設置表格項數據，關鍵代碼：當role為Qt::UserRole時候，會調用onStateChanged()函數，來更新表頭！

• onStateChanged
  復選狀態改變，通知表頭更新復選狀態。

• onStateChanged(int state)
  槽函數，接收表頭復選狀態更新變化，改動表格復選狀態。

使用

這時，就須要將header與model的信號與槽關聯起來，更新復選框狀態了！

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)));