Reimplement paint() in QItemDelegate

[john_erlandsson]

Hi!

I have subclassed a QSqlQueryModel and a QItemDelegate. Making a column containing a date editable, and displayed as a QCheckBox. Cell contains a date = checked cell is null = not checked. Checking a cell = insert todays date, unchecking a cell = set date to "".

The only thing left to do is to allways display the checkbox delegate, even when not editing. After a bit of googling I found out that i have to reimplement the paint() function in my QItemDelegate, to display a CheckBox instead of text.

The problem is that i have no idea where to begin. The manual gives a short example, but it doesent make much sense to me.

Does anyone know of a better example?

The implementation of my QItemDelegate (Basically yanked from the SpinBoxDelegate example):

#include "economyhoursattdelegate.h"
#include <QCheckBox>
#include <QDate>
 
/* Constructor
 *
 */
EconomyHoursAttDelegate::EconomyHoursAttDelegate(QObject *parent) :
    QItemDelegate(parent)
{
}
 
/* Reimplemented function: createEditor
 * Create a QCheckbox in the att column
 */
QWidget *EconomyHoursAttDelegate::createEditor( QWidget *parent, const QStyleOptionViewItem &/*option*/,
                                                const QModelIndex &/*index*/ ) const
{
    QCheckBox *editor = new QCheckBox( parent );
 
    return editor;
}
 
/* Reimplemented function: setEditorData
 * Set the checkbox checked if cell contains a date
 */
void EconomyHoursAttDelegate::setEditorData( QWidget *editor, const QModelIndex &index ) const
{
    QString value = index.model()->data( index, Qt::EditRole ).toString();
 
    QCheckBox *checkBox = static_cast<QCheckBox*>(editor);
 
    bool checked = value == "" ? false : true;
 
    checkBox->setChecked( checked );
}
 
/* Reimplemented function: setModelData
 * Set model data to todays date if the checkbox is checked
 */
void EconomyHoursAttDelegate::setModelData( QWidget *editor, QAbstractItemModel *model,
                                            const QModelIndex &index ) const
{
    QCheckBox *checkBox = static_cast<QCheckBox*>(editor);
 
    QDate now = QDate::currentDate();
 
    if( checkBox->isChecked() )
        model->setData( index, now, Qt::EditRole );
    else
        model->setData( index, QString(), Qt::EditRole );
}
 
/* Reimplemented function: updateEditorGeometry
 * Adjust the size of the checkbox to fit the cell size
 */
void EconomyHoursAttDelegate::updateEditorGeometry( QWidget *editor, const QStyleOptionViewItem &option,
                                                    const QModelIndex &/*index*/ ) const
{
    editor->setGeometry( option.rect );
}

#include "economyhoursattdelegate.h"
#include <QCheckBox>
#include <QDate>

/* Constructor
 *
 */
EconomyHoursAttDelegate::EconomyHoursAttDelegate(QObject *parent) :
    QItemDelegate(parent)
{
}

/* Reimplemented function: createEditor
 * Create a QCheckbox in the att column
 */
QWidget *EconomyHoursAttDelegate::createEditor( QWidget *parent, const QStyleOptionViewItem &/*option*/,
                                                const QModelIndex &/*index*/ ) const
{
    QCheckBox *editor = new QCheckBox( parent );

    return editor;
}

/* Reimplemented function: setEditorData
 * Set the checkbox checked if cell contains a date
 */
void EconomyHoursAttDelegate::setEditorData( QWidget *editor, const QModelIndex &index ) const
{
    QString value = index.model()->data( index, Qt::EditRole ).toString();

    QCheckBox *checkBox = static_cast<QCheckBox*>(editor);

    bool checked = value == "" ? false : true;

    checkBox->setChecked( checked );
}

/* Reimplemented function: setModelData
 * Set model data to todays date if the checkbox is checked
 */
void EconomyHoursAttDelegate::setModelData( QWidget *editor, QAbstractItemModel *model,
                                            const QModelIndex &index ) const
{
    QCheckBox *checkBox = static_cast<QCheckBox*>(editor);

    QDate now = QDate::currentDate();

    if( checkBox->isChecked() )
        model->setData( index, now, Qt::EditRole );
    else
        model->setData( index, QString(), Qt::EditRole );
}

/* Reimplemented function: updateEditorGeometry
 * Adjust the size of the checkbox to fit the cell size
 */
void EconomyHoursAttDelegate::updateEditorGeometry( QWidget *editor, const QStyleOptionViewItem &option,
                                                    const QModelIndex &/*index*/ ) const
{
    editor->setGeometry( option.rect );
}

To copy to clipboard, switch view to plain text mode 

Any help is apreciated...

//John

[wysota]

How about using Qt::CheckStateRole in your model instead?

[john_erlandsson]

How about using Qt::CheckStateRole in your model instead?

I am sorry, but i don't follow. Could you elaborate?

This is the implementation of my model:

#include "economyhoursmodel.h"
#include <QSqlQuery>
#include <QDebug>
 
/* Constructor
 *
 */
EconomyHoursModel::EconomyHoursModel( QObject *parent ) :
    QSqlQueryModel( parent )
{
}
 
/* Reimplemented function: flags
 * Set the att coulumn editable flag
 */
Qt::ItemFlags EconomyHoursModel::flags( const QModelIndex &index ) const
{
    Qt::ItemFlags flags = QSqlQueryModel::flags( index );
 
    if( index.column() == 3 )
        flags |= Qt::ItemIsEditable;
 
    return flags;
}
 
/* Reimplemented function: setData
 * Sets data for the att column
 */
bool EconomyHoursModel::setData( const QModelIndex &index, const QVariant &value, int /*role*/ )
{
    if( index.column() != 3 )
        return false;
 
    QModelIndex idIndex = QSqlQueryModel::index( index.row(), 4 );
 
    int id = data( idIndex ).toInt();
 
    clear();
 
    QSqlQuery query;
    query.prepare( "UPDATE hours SET att=? WHERE id=?" );
    query.addBindValue( value );
    query.addBindValue( id );
 
    bool ret = query.exec();
 
    if( ret )
        refresh();
 
    return ret;
}
 
/* Public function: refresh
 * Refresh the query with current start and end date
 */
void EconomyHoursModel::refresh()
{
    QSqlQuery query;
 
    query.prepare( "SELECT hours.date, hours.hours, repairmen.name, hours.att, hours.id\n"
                   "FROM hours\n"
                   "LEFT JOIN repairmen\n"
                   "ON repairmen.id=hours.repairmen_id\n"
                   "WHERE hours.date>=? AND hours.date<=?;" );
    query.addBindValue( StartDate );
    query.addBindValue( EndDate );
 
    query.exec();
 
    setQuery( query );
 
    setHeaderData( 0, Qt::Horizontal, "Datum" );
    setHeaderData( 1, Qt::Horizontal, "Antal" );
    setHeaderData( 2, Qt::Horizontal, "Reparatör" );
    setHeaderData( 3, Qt::Horizontal, "Att" );
    setHeaderData( 4, Qt::Horizontal, "ID" );
}
 
/* Public function: setStartDate
 * set start date for the query and refresh
 */
void EconomyHoursModel::setStartDate( QDate date )
{
    StartDate = date;
    refresh();
}
 
/* Public function: setEndDate
 * set end date for the query and refresh
 */
void EconomyHoursModel::setEndDate( QDate date )
{
    EndDate = date;
    refresh();
}

#include "economyhoursmodel.h"
#include <QSqlQuery>
#include <QDebug>

/* Constructor
 *
 */
EconomyHoursModel::EconomyHoursModel( QObject *parent ) :
    QSqlQueryModel( parent )
{
}

/* Reimplemented function: flags
 * Set the att coulumn editable flag
 */
Qt::ItemFlags EconomyHoursModel::flags( const QModelIndex &index ) const
{
    Qt::ItemFlags flags = QSqlQueryModel::flags( index );

    if( index.column() == 3 )
        flags |= Qt::ItemIsEditable;

    return flags;
}

/* Reimplemented function: setData
 * Sets data for the att column
 */
bool EconomyHoursModel::setData( const QModelIndex &index, const QVariant &value, int /*role*/ )
{
    if( index.column() != 3 )
        return false;

    QModelIndex idIndex = QSqlQueryModel::index( index.row(), 4 );

    int id = data( idIndex ).toInt();

    clear();

    QSqlQuery query;
    query.prepare( "UPDATE hours SET att=? WHERE id=?" );
    query.addBindValue( value );
    query.addBindValue( id );

    bool ret = query.exec();

    if( ret )
        refresh();

    return ret;
}

/* Public function: refresh
 * Refresh the query with current start and end date
 */
void EconomyHoursModel::refresh()
{
    QSqlQuery query;

    query.prepare( "SELECT hours.date, hours.hours, repairmen.name, hours.att, hours.id\n"
                   "FROM hours\n"
                   "LEFT JOIN repairmen\n"
                   "ON repairmen.id=hours.repairmen_id\n"
                   "WHERE hours.date>=? AND hours.date<=?;" );
    query.addBindValue( StartDate );
    query.addBindValue( EndDate );

    query.exec();

    setQuery( query );

    setHeaderData( 0, Qt::Horizontal, "Datum" );
    setHeaderData( 1, Qt::Horizontal, "Antal" );
    setHeaderData( 2, Qt::Horizontal, "Reparatör" );
    setHeaderData( 3, Qt::Horizontal, "Att" );
    setHeaderData( 4, Qt::Horizontal, "ID" );
}

/* Public function: setStartDate
 * set start date for the query and refresh
 */
void EconomyHoursModel::setStartDate( QDate date )
{
    StartDate = date;
    refresh();
}

/* Public function: setEndDate
 * set end date for the query and refresh
 */
void EconomyHoursModel::setEndDate( QDate date )
{
    EndDate = date;
    refresh();
}

To copy to clipboard, switch view to plain text mode 

[wysota]

Check state role allows you to store information about each item in regards of whether it is checked or unchecked and display and edit that information using a standard delegate. I'm sure some of Qt model-view examples demonstrate it.

[john_erlandsson]

Solved it!

Nice solution. I removed my delegate and reimplemented these functions in my model:

/* Reimplemented function: flags
 * Set the att coulumn editable flag
 */
Qt::ItemFlags EconomyHoursModel::flags( const QModelIndex &index ) const
{
    Qt::ItemFlags flags = QSqlQueryModel::flags( index );
 
    if( index.column() == 5 )
        flags |= Qt::ItemIsEditable | Qt::ItemIsUserCheckable;
 
    return flags;
}
 
/* Reimplemented function: data
 * Have to reimplement this in order to show a checkbox when not editing the table
 */
QVariant EconomyHoursModel::data(const QModelIndex &index, int role) const
{
    QVariant ret;
 
    if( role == Qt::CheckStateRole && index.column() == 5 )
    {
        if( QSqlQueryModel::data( index, Qt::DisplayRole ).toString() == "" )
            ret = Qt::Unchecked;
        else
            ret = Qt::Checked;
    }
    else if( role == Qt::DisplayRole && index.column() == 5 ) //Don't show date as text
    {
        ret = QVariant();
    }
    else
    {
        ret = QSqlQueryModel::data( index, role );
    }
 
    return ret;
}
 
/* Reimplemented function: setData
 * Sets data for the att column
 */
bool EconomyHoursModel::setData( const QModelIndex &index, const QVariant &value, int role )
{
    bool ret = false;
 
    if( role == Qt::CheckStateRole )
    {
        if( index.column() != 5 )
            return false;
 
        QModelIndex idIndex = QSqlQueryModel::index( index.row(), 0 );
 
        int id = data( idIndex ).toInt();
 
        QString storeValue = "";
 
        if( value.toInt() == Qt::Checked )
            storeValue = QDate::currentDate().toString( "yyyy-MM-dd" );
 
        clear();
 
        QSqlQuery query;
        query.prepare( "UPDATE hours SET att=? WHERE id=?" );
        query.addBindValue( storeValue );
        query.addBindValue( id );
 
        ret = query.exec();
 
        if( ret )
            refresh();
    }
    else
    {
        ret = QSqlQueryModel::setData( index, value, role );
    }
 
    return ret;
}

/* Reimplemented function: flags
 * Set the att coulumn editable flag
 */
Qt::ItemFlags EconomyHoursModel::flags( const QModelIndex &index ) const
{
    Qt::ItemFlags flags = QSqlQueryModel::flags( index );

    if( index.column() == 5 )
        flags |= Qt::ItemIsEditable | Qt::ItemIsUserCheckable;

    return flags;
}

/* Reimplemented function: data
 * Have to reimplement this in order to show a checkbox when not editing the table
 */
QVariant EconomyHoursModel::data(const QModelIndex &index, int role) const
{
    QVariant ret;

    if( role == Qt::CheckStateRole && index.column() == 5 )
    {
        if( QSqlQueryModel::data( index, Qt::DisplayRole ).toString() == "" )
            ret = Qt::Unchecked;
        else
            ret = Qt::Checked;
    }
    else if( role == Qt::DisplayRole && index.column() == 5 ) //Don't show date as text
    {
        ret = QVariant();
    }
    else
    {
        ret = QSqlQueryModel::data( index, role );
    }

    return ret;
}

/* Reimplemented function: setData
 * Sets data for the att column
 */
bool EconomyHoursModel::setData( const QModelIndex &index, const QVariant &value, int role )
{
    bool ret = false;

    if( role == Qt::CheckStateRole )
    {
        if( index.column() != 5 )
            return false;

        QModelIndex idIndex = QSqlQueryModel::index( index.row(), 0 );

        int id = data( idIndex ).toInt();

        QString storeValue = "";

        if( value.toInt() == Qt::Checked )
            storeValue = QDate::currentDate().toString( "yyyy-MM-dd" );

        clear();

        QSqlQuery query;
        query.prepare( "UPDATE hours SET att=? WHERE id=?" );
        query.addBindValue( storeValue );
        query.addBindValue( id );

        ret = query.exec();

        if( ret )
            refresh();
    }
    else
    {
        ret = QSqlQueryModel::setData( index, value, role );
    }

    return ret;
}

To copy to clipboard, switch view to plain text mode 

Thanks for pointing me in the right direction!!!

//John