QTableView Date display format difference linux vs. Windows

[schnitzel]

I wrote an application that displays a table from a mysql db using QTableView. One of the columns is a Date.

On Windows it displays as yyyy-mm-dd but on linux is shows as yy-mm-dd.

Same code, same database.

The database lives on the Windows machine.

I have verified that the date format of the database is correct by using MySQL Query Browser running on the Linux machine.

Did I overlook something?

[Rhayader]

what you get by running the next code?

#include <QtCore/QCoreApplication>
#include <QLocale>
#include <QDebug>
 
int main(int argc, char *argv[])
{
    QCoreApplication a(argc, argv);
    QLocale l=QLocale::system();
    qDebug()<<l.dateFormat(QLocale::ShortFormat);
    return a.exec();
}

#include <QtCore/QCoreApplication>
#include <QLocale>
#include <QDebug>

int main(int argc, char *argv[])
{
    QCoreApplication a(argc, argv);
    QLocale l=QLocale::system();
    qDebug()<<l.dateFormat(QLocale::ShortFormat);
    return a.exec();
}

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[schnitzel]

on windows: yyyy-mm-dd
on linux: M/d/yy

I know how to change the short date format on Windows... if I could only figure out how to do this on linux system wide.

---

Added after 1 48 minutes:

Tried both methods described on the following page:

http://ccollins.wordpress.com/2009/0...ats-on-ubuntu/

still the output from the above sample code still shows: "M/d/yy"

very frustrating...

[schnitzel]

Ok, just to recap.

I'm on Ubuntu 10.10 vanilla Qt 4.7.0.
default locale was en_US with short date M/d/yy which sucks.
I then changed locale to en_CA and got yy-MM-dd which is better but I'd like 4 digits for year.
I then changed locale en_CA d_fmt to %Y-%m-%d (and recompiled the locale), yet Qt sample code still gives:
yy-MM-dd
I even tried to change d_fmt to %F (confirmed with date +%F) result still:
yy-MM-dd

I'm extremely

[Rhayader]

This is a delegate I use for an application of my own. It is mostly copy-paste from the Qt examples and works fine for me.
the datedelegate.h:

#ifndef DATEDELEGATE_H
#define DATEDELEGATE_H
 
#include <QStyledItemDelegate>
class QStyleOptionViewItem;
 
class DateDelegate : public QStyledItemDelegate
{
Q_OBJECT
public:
     DateDelegate(QObject *parent = 0,const int &dateColumn=0);
 
     QWidget *createEditor(QWidget *parent, const QStyleOptionViewItem &option,
                           const QModelIndex &index) const;
 
     void setEditorData(QWidget *editor, const QModelIndex &index) const;
     void setModelData(QWidget *editor, QAbstractItemModel *model,
                       const QModelIndex &index) const;
     void updateEditorGeometry(QWidget *editor,
         const QStyleOptionViewItem &option, const QModelIndex &index) const;
     void paint(QPainter *painter, const QStyleOptionViewItem &option,
                               const QModelIndex &index) const;
 
signals:
 
public slots:
private:
     int dtC;
 
};
 
#endif // DATEDELEGATE_H

#ifndef DATEDELEGATE_H
#define DATEDELEGATE_H

#include <QStyledItemDelegate>
class QStyleOptionViewItem;

class DateDelegate : public QStyledItemDelegate
{
Q_OBJECT
public:
     DateDelegate(QObject *parent = 0,const int &dateColumn=0);

     QWidget *createEditor(QWidget *parent, const QStyleOptionViewItem &option,
                           const QModelIndex &index) const;

     void setEditorData(QWidget *editor, const QModelIndex &index) const;
     void setModelData(QWidget *editor, QAbstractItemModel *model,
                       const QModelIndex &index) const;
     void updateEditorGeometry(QWidget *editor,
         const QStyleOptionViewItem &option, const QModelIndex &index) const;
     void paint(QPainter *painter, const QStyleOptionViewItem &option,
                               const QModelIndex &index) const;

signals:

public slots:
private:
     int dtC;

};

#endif // DATEDELEGATE_H

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and the datedelegate.cpp

#include "datedelegate.h"
#include <QStyleOptionViewItem>
#include <QModelIndex>
#include <QDateEdit>
#include <QPainter>
#include <QApplication>
#include <QTableView>
#include <QDebug>
 
DateDelegate::DateDelegate(QObject *parent, const int &dateColumn) :
    QStyledItemDelegate(parent),dtC (dateColumn)
{
}
 
QWidget *DateDelegate::createEditor(QWidget *parent,
     const QStyleOptionViewItem &option,
     const QModelIndex &index) const
 {
    if(index.isValid() && index.column() == dtC)
    {
        QWidget *editor = new QDateEdit(QDate::currentDate(), parent);
        return editor;
    }
    else
        return QStyledItemDelegate::createEditor(parent, option, index);
 }
 
void DateDelegate::setEditorData(QWidget *editor,
                                     const QModelIndex &index) const
 {
    if(index.isValid() && index.column() == dtC)
    {
     QDate value = index.model()->data(index, Qt::EditRole).toDate();
 
     QDateEdit *dateEdit = static_cast<QDateEdit*>(editor);
     dateEdit->setCalendarPopup(true);
     dateEdit->setDate(value);
    }
    else
        QStyledItemDelegate::setEditorData(editor,index);
 }
 
void DateDelegate::setModelData(QWidget *editor, QAbstractItemModel *model,
                                    const QModelIndex &index) const
 {
    if(index.isValid() && index.column() == dtC)
    {
        QDateEdit *dateEdit = static_cast<QDateEdit*>(editor);
        QDate value = dateEdit->date();
 
        model->setData(index, value.toString("yyyy-MM-dd"), Qt::EditRole);
    }
 
    else
    {
        QStyledItemDelegate::setModelData(editor,model,index);
    }
 }
 
void DateDelegate::updateEditorGeometry(QWidget *editor, const QStyleOptionViewItem &option,
                                        const QModelIndex &index) const
{
    if(index.isValid() && index.column() == dtC)
        editor->setGeometry(option.rect);
    else
            QStyledItemDelegate::updateEditorGeometry(editor, option, index);
 
}
 
void DateDelegate::paint(QPainter *painter, const QStyleOptionViewItem &option,
                          const QModelIndex &index) const
 {
    painter->save();
     if(index.isValid() && index.column() == dtC)
    {
         QDate value = index.model()->data(index, Qt::EditRole).toDate();
         if (option.state & QStyle::State_Active)
         {
            QApplication::style()->drawItemText(painter, option.rect, Qt::AlignHCenter|Qt::AlignVCenter,
                                             option.palette, true, value.toString("dd/MM/yyyy"),
                   (option.state&QStyle::State_Selected)?QPalette::HighlightedText:QPalette::WindowText);
        }
         else
         {
             QApplication::style()->drawItemText(painter, option.rect, Qt::AlignHCenter|Qt::AlignVCenter,
                                              option.palette, true, value.toString("dd/MM/yyyy"),
                    QPalette::WindowText);
         }
    }
     else
     {
         QStyledItemDelegate::paint(painter, option, index);
     }
     painter->restore();
 }

#include "datedelegate.h"
#include <QStyleOptionViewItem>
#include <QModelIndex>
#include <QDateEdit>
#include <QPainter>
#include <QApplication>
#include <QTableView>
#include <QDebug>

DateDelegate::DateDelegate(QObject *parent, const int &dateColumn) :
    QStyledItemDelegate(parent),dtC (dateColumn)
{
}

QWidget *DateDelegate::createEditor(QWidget *parent,
     const QStyleOptionViewItem &option,
     const QModelIndex &index) const
 {
    if(index.isValid() && index.column() == dtC)
    {
        QWidget *editor = new QDateEdit(QDate::currentDate(), parent);
        return editor;
    }
    else
        return QStyledItemDelegate::createEditor(parent, option, index);
 }

void DateDelegate::setEditorData(QWidget *editor,
                                     const QModelIndex &index) const
 {
    if(index.isValid() && index.column() == dtC)
    {
     QDate value = index.model()->data(index, Qt::EditRole).toDate();

     QDateEdit *dateEdit = static_cast<QDateEdit*>(editor);
     dateEdit->setCalendarPopup(true);
     dateEdit->setDate(value);
    }
    else
        QStyledItemDelegate::setEditorData(editor,index);
 }

void DateDelegate::setModelData(QWidget *editor, QAbstractItemModel *model,
                                    const QModelIndex &index) const
 {
    if(index.isValid() && index.column() == dtC)
    {
        QDateEdit *dateEdit = static_cast<QDateEdit*>(editor);
        QDate value = dateEdit->date();

        model->setData(index, value.toString("yyyy-MM-dd"), Qt::EditRole);
    }

    else
    {
        QStyledItemDelegate::setModelData(editor,model,index);
    }
 }

void DateDelegate::updateEditorGeometry(QWidget *editor, const QStyleOptionViewItem &option,
                                        const QModelIndex &index) const
{
    if(index.isValid() && index.column() == dtC)
        editor->setGeometry(option.rect);
    else
            QStyledItemDelegate::updateEditorGeometry(editor, option, index);

}

void DateDelegate::paint(QPainter *painter, const QStyleOptionViewItem &option,
                          const QModelIndex &index) const
 {
    painter->save();
     if(index.isValid() && index.column() == dtC)
    {
         QDate value = index.model()->data(index, Qt::EditRole).toDate();
         if (option.state & QStyle::State_Active)
         {
            QApplication::style()->drawItemText(painter, option.rect, Qt::AlignHCenter|Qt::AlignVCenter,
                                             option.palette, true, value.toString("dd/MM/yyyy"),
                   (option.state&QStyle::State_Selected)?QPalette::HighlightedText:QPalette::WindowText);
        }
         else
         {
             QApplication::style()->drawItemText(painter, option.rect, Qt::AlignHCenter|Qt::AlignVCenter,
                                              option.palette, true, value.toString("dd/MM/yyyy"),
                    QPalette::WindowText);
         }
    }
     else
     {
         QStyledItemDelegate::paint(painter, option, index);
     }
     painter->restore();
 }

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The writing to model is done in line 51 in ISO format for a SQLite database.
Change lines 80 and 86 to whatever format you like for the tableView.

And for the sake of completeness:

#include "datedelegate.h"
......
DateDelegate dateDelegate=new DateDelegate(this,column);
ui->tableView->setItemDelegate(dateDelegate);
......

#include "datedelegate.h"
......
DateDelegate dateDelegate=new DateDelegate(this,column);
ui->tableView->setItemDelegate(dateDelegate);
......

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It is possible to rewrite the delegate without the column variable and use the setItemDelegateForColumn method of the tableView.

---

Added after 14 minutes:

Having just read the QLocale source code I think the LC_TIME is never read and I would not mess with the LANG or LC_ALL in my working machine. So just for the fun of it I wrote this trying to override what Qt reads from system

#include <QtCore/QCoreApplication>
#include <QLocale>
#include <QDebug>
#include <QVariant>
#include <QDate>
 
class MyLocal : QSystemLocale
{
#include <QSystemLocale>
public:
    MyLocal() { };
 
    QVariant query(QueryType type, QVariant in) const
    {
        if (type==QSystemLocale::DateToStringShort)
        {
            QDate inDate=in.toDate();
            return inDate.toString("yy-M-d");
        }
        else if (type==QSystemLocale::DateToStringLong)
        {
            QDate inDate=in.toDate();
            return inDate.toString("yyyy-MM-dd");
        }
        return QSystemLocale::query(type, in);
    }
};
 
int main(int argc, char *argv[])
{
    QCoreApplication a(argc, argv);
    MyLocal m;
    qDebug()<<QDate::currentDate().toString(Qt::DefaultLocaleShortDate);
    qDebug()<<QDate::currentDate().toString(Qt::DefaultLocaleLongDate);
    return a.exec();
}

#include <QtCore/QCoreApplication>
#include <QLocale>
#include <QDebug>
#include <QVariant>
#include <QDate>

class MyLocal : QSystemLocale
{
#include <QSystemLocale>
public:
    MyLocal() { };

    QVariant query(QueryType type, QVariant in) const
    {
        if (type==QSystemLocale::DateToStringShort)
        {
            QDate inDate=in.toDate();
            return inDate.toString("yy-M-d");
        }
        else if (type==QSystemLocale::DateToStringLong)
        {
            QDate inDate=in.toDate();
            return inDate.toString("yyyy-MM-dd");
        }
        return QSystemLocale::query(type, in);
    }
};

int main(int argc, char *argv[])
{
    QCoreApplication a(argc, argv);
    MyLocal m;
    qDebug()<<QDate::currentDate().toString(Qt::DefaultLocaleShortDate);
    qDebug()<<QDate::currentDate().toString(Qt::DefaultLocaleLongDate);
    return a.exec();
}

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which is pretty stupid because the same could be done pretty simple as
QDate::currentDate().toString("yy-MM-dd")

[schnitzel]

Hi Rhayader,
thanks for investigating. I'll play around with this tonight.

[schnitzel]

overriding QSystemLocale worked like a charm.