Qt之QHeaderView添加复选框

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！

简述

效果

QHeaderView
源码

接口说明

QAbstractTableModel
源码

接口说明

使用

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)));