How to set Checkbox in header of one column in QtreeView

[Qt Enthusiast]

Hi All
We need to set checkbox in header of one of the columns . I have following class

class MyHeader : public QHeaderView
{
public:
MyHeader(Qt::Orientation orientation, QWidget * parent = 0) : QHeaderView(orientation, parent)
{}

protected:
void paintSection(QPainter *painter, const QRect &rect, int logicalIndex) const
{
painter->save();
QHeaderView::paintSection(painter, rect, logicalIndex);
painter->restore();
if (logicalIndex == 0)
{
QStyleOptionButton option;
option.rect = QRect(10,10,10,10);
if (isOn)
option.state = QStyle::State_On;
else
option.state = QStyle::State_Off;
this->style()->drawPrimitive(QStyle::PE_IndicatorCheckBox, &option, painter);
}

}
void mousePressEvent(QMouseEvent *event)
{
if (isOn)
isOn = false;
else
isOn = true;
this->update();
QHeaderView::mousePressEvent(event);
}
private:
bool isOn;
};

class myView::QTreeView {

}

MyView::GQInstView(QWidget* dparent)
: QTreeView(dparent), {

}

The tree View has three columns . How to set header for first column in treeView

[Ratzz]

@Qt-Enthusiast
Is this the same post of https://forum.qt.io/topic/67574/can-we-have-checkbox-in-header-of-qtreeview-along-with-sorting-symbol/

[mrjj]

• The tree View has three columns . How to set header for first column in treeView

Hi
I do not think you can replace for just column 1
You can set for treeview using
http://doc.qt.io/qt-5/qtreeview.html#setHeader
and that be for all columns.

[raven-worx]

@Qt-Enthusiast

1. set your custom header view to your items widget like @mrjj said
2. instead of using "isOn" in the header class, query the model's headerData() method for the Qt::CheckStateRole
3. in your model return the corresponding check state in headerData(). For column 1 return Qt::Checked, when you don't want to display a checkbox at all return an invalid QVariant

[Qt Enthusiast]

@raven-worx said:

odel's headerData() method for the Qt::CheckStateRole
in your model return the corresponding check state in

how to get model pointer

class MyHeader : public QHeaderView
{
public:
MyHeader(Qt::Orientation orientation, QWidget * parent = 0) : QHeaderView(orientation, parent)
{}

protected:
void paintSection(QPainter *painter, const QRect &rect, int logicalIndex) const
{
painter->save();
QHeaderView::paintSection(painter, rect, logicalIndex);
painter->restore();
if (logicalIndex == 0)
{
QStyleOptionButton option;
option.rect = QRect(10,10,10,10);
if (isOn)
option.state = QStyle::State_On;
else
option.state = QStyle::State_Off;
this->style()->drawPrimitive(QStyle::PE_IndicatorCheckBox, &option, painter);
}

}
void mousePressEvent(QMouseEvent *event)
{
if (isOn)
isOn = false;
else
isOn = true;
this->update();
QHeaderView::mousePressEvent(event);
}
private:
bool isOn;
};

[raven-worx]

@Qt-Enthusiast said:

how to get model pointer

since QHeaderView derives from QAbstractItemView, you are doing it the same way you would do for table/trees/lists/... with the model() method
This model is the same as the item view widget has also set.

[Qt Enthusiast]

@raven-worx

#include <QApplication>
#include <QAbstractTableModel>
#include <QSortFilterProxyModel>
#include <QInputDialog>
#include <QTableView>
#include <QGridLayout>
#include <QPushButton>
#include <QDebug>
#include <QHeaderView>
#include <QStyle>
#include <QPainter>
#include <QMouseEvent>
#include <QTreeView>

class MyHeader : public QHeaderView
{
public:
MyHeader(Qt::Orientation orientation, QWidget * parent = 0) : QHeaderView(orientation, parent)
{}

protected:
void paintSection(QPainter *painter, const QRect &rect, int logicalIndex) const
{
painter->save();
QHeaderView::paintSection(painter, rect, logicalIndex);
painter->restore();
if (logicalIndex == 1 )
{
QStyleOptionButton option;
option.rect = QRect(10,10,10,10);
isOn = model()->headerData(1,Qt::Horizontal, Qt::CheckStateRole);
if (isOn)
option.state = QStyle::State_On;
else
option.state = QStyle::State_Off;
this->style()->drawPrimitive(QStyle::PE_IndicatorCheckBox, &option, painter);
}

}
void mousePressEvent(QMouseEvent *event)
{

if (isOn)
  isOn = false;
else
  isOn = true;
this->update();
QHeaderView::mousePressEvent(event);

}
private:
bool isOn;
};

class Vehicle {
QString m_make, m_model, m_registrationNumber;
public:
Vehicle(const QString & make, const QString & model, const QString & registrationNumber = QString()) :
m_make(make), m_model(model), m_registrationNumber(registrationNumber) {}
QString make() const { return m_make; }
QString model() const { return m_model; }
QString registrationNumber() const { return m_registrationNumber; }
bool isRegistered() const { return !m_registrationNumber.isEmpty(); }
};

class VehicleModel : public QAbstractTableModel {
QList<Vehicle> m_data;
public:
VehicleModel(QObject * parent = 0) : QAbstractTableModel(parent) {}
int rowCount(const QModelIndex &) const { return m_data.count(); }
int columnCount(const QModelIndex &) const { return 3; }
QVariant data(const QModelIndex &index, int role) const {
if (role != Qt::DisplayRole && role != Qt::EditRole) return QVariant();
const Vehicle & vehicle = m_data[index.row()];
switch (index.column()) {
case 0: return vehicle.make();
case 1: return vehicle.model();
case 2: return vehicle.registrationNumber();
default: return QVariant();
};
}
QVariant headerData(int section, Qt::Orientation orientation, int role) const {
if(role == Qt::CheckStateRole && orientation == Qt::Horizontal) {
switch (section) {
case 0: return Qt::Unchecked;
case 1: return Qt::Checked;
case 2: return Qt::Unchecked;
default: return QVariant();
}

    }
    if (orientation != Qt::Horizontal) return QVariant();
    if (role != Qt::) return QVariant();
    switch (section) {
    case 0: return "Make";
    case 1: return "Model";
    case 2: return "Reg.#";
    default: return QVariant();
    }
}
void append(const Vehicle & vehicle) {
    beginInsertRows(QModelIndex(), m_data.count(), m_data.count());
    m_data.append(vehicle);
    endInsertRows();
}

};

class Widget : public QWidget {

VehicleModel m_model;
QSortFilterProxyModel m_proxy;
Q_SLOT void setFilter() {
    QInputDialog * dialog = new QInputDialog(this);
    dialog->setLabelText("Enter registration number fragment to filter on. Leave empty to clear filter.");
    dialog->setInputMode(QInputDialog::TextInput);
    dialog->open(&m_proxy, SLOT(setFilterFixedString(QString)));
    dialog->setAttribute(Qt::WA_DeleteOnClose);
}

public:
Widget() {
QGridLayout * layout = new QGridLayout(this);
QTreeView view = new QTreeView;
MyHeader myH = new MyHeader(Qt::Horizontal);
view->setHeader(myH);
layout->addWidget(view, 0, 0, 1, 1);
QPushButton * btn = new QPushButton("Filter");
layout->addWidget(btn, 1, 0, 1, 1);
m_model.append(Vehicle("Volvo", "240", "SQL8941"));
m_model.append(Vehicle("Volvo", "850"));
m_model.append(Vehicle("Volvo", "940", "QRZ1321"));
m_model.append(Vehicle("Volvo", "960", "QRZ1628"));
view->setModel(&m_model);
}
};

int main(int argc, char *argv[])
{
QApplication a(argc, argv);
Widget w;
w.show();
return a.exec();
}

could you guide me on the same how to have checkbox in above code as per your inputs

[Sam]

Have a look at this Qt blog https://blog.qt.io/blog/2012/09/28/qt-support-weekly-27-widgets-on-a-header/

[raven-worx]

@Qt-Enthusiast said:

could you guide me on the same how to have checkbox in above code as per your inputs

i just give you some snippets. I leave it to you to check the rest out, since it's pretty simple.

in the header:

void MyHeaderView::paintSection(QPainter *painter, const QRect &rect, int logicalIndex) const
{
painter->save();
QHeaderView::paintSection(painter, rect, logicalIndex);
painter->restore();

QVariant headerCheckState = model()->headerData(logicalIndex, Qt::Horizontal, Qt::CheckStateRole);

if( headerCheckState .isValid() )  //only paint the checkbox if the model returned a valid qvariant
{
Qt::CheckState check = static_cast<Qt::CheckState>( headerCheckState.toInt() );
QStyleOptionButton option;
option.rect = QRect(10,10,10,10);
if ( checkState == Qt::Checked )
      option.state = QStyle::State_On;
else
      option.state = QStyle::State_Off;
this->style()->drawPrimitive(QStyle::PE_IndicatorCheckBox, &option, painter);
}

in the model:

QVariant MyModel::headerData(int section, Qt::Orientation orientation, int role ) const
{
     if( orientation == Qt::Horizontal )
     {
               switch( role )
               {
                      case Qt::CheckStateRole:
                      {
                                 if( section == XXX )  // here you need to check which columns you want to display the checkbox
                                 {
                                        return QVariant::fromValue<int>(Qt::Checked);
                                 }
                      }
                      break;
               }
     }

      return QHeaderView::headerData(section,orientation,role);
}

This way a checkbox is only displayed when you return a valid QVariant:

Invalid QVariant -> no checkbox
QVariant with Qt::CheckedState -> checked checkbox
QVariant with other value -> unchecked checkbox