The precision range of double

[ChrisW67]

I do not edit the contents of the table, I only click on the column header of the tableview, such that the sorting of Ascending and Descending happens.

This useful?

#include <QtGui>
#include <QDebug>
#include <QStandardItemModel>
 
int main(int argc, char *argv[])
{
 
    QApplication app(argc, argv);
 
    QStandardItemModel model(10, 2);
    model.setSortRole(Qt::EditRole);
    for (int row = 0; row < 10; ++row) {
        qreal value = row * 1.2345678;
        QString text;
        text.setNum(value, 'g', 10);
 
        //  Column with only a user readable DisplayRole
        QStandardItem *item1 = new QStandardItem(text);
        model.setItem(row, 0, item1);
 
        // Column with sortable EditRole
        QStandardItem *item2 = new QStandardItem(text);
        item2->setData(value, Qt::EditRole);
        model.setItem(row, 1, item2);
    }
 
    QTableView tv;
    tv.setModel(&model);
    tv.setSortingEnabled(true);
    tv.horizontalHeader()->setSortIndicator(0, Qt::AscendingOrder);
    tv.horizontalHeader()->setSortIndicator(1, Qt::AscendingOrder);
    tv.show();
 
    return app.exec();
}
 
// vi: sw=4 ts=4 et

#include <QtGui>
#include <QDebug>
#include <QStandardItemModel>

int main(int argc, char *argv[])
{

    QApplication app(argc, argv);

    QStandardItemModel model(10, 2);
    model.setSortRole(Qt::EditRole);
    for (int row = 0; row < 10; ++row) {
        qreal value = row * 1.2345678;
        QString text;
        text.setNum(value, 'g', 10);

        //  Column with only a user readable DisplayRole
        QStandardItem *item1 = new QStandardItem(text);
        model.setItem(row, 0, item1);

        // Column with sortable EditRole
        QStandardItem *item2 = new QStandardItem(text);
        item2->setData(value, Qt::EditRole);
        model.setItem(row, 1, item2);
    }

    QTableView tv;
    tv.setModel(&model);
    tv.setSortingEnabled(true);
    tv.horizontalHeader()->setSortIndicator(0, Qt::AscendingOrder);
    tv.horizontalHeader()->setSortIndicator(1, Qt::AscendingOrder);
    tv.show();

    return app.exec();
}

// vi: sw=4 ts=4 et

To copy to clipboard, switch view to plain text mode 

Column 1 sorts based on the string representation. Column 2 sorts numerically but displays in default format.

[faldzip]

for me this is working as it should:

#include "mainwindow.h"
#include "ui_mainwindow.h"
 
#include <QStyledItemDelegate>
 
class MyDelegate : public QStyledItemDelegate
{
public:
	MyDelegate(QObject *parent = 0) : QStyledItemDelegate(parent) { }
	QString displayText(const QVariant &value, const QLocale &locale) const {
		if (value.type() == QVariant::Double) return locale.toString(value.toDouble(), 'g', 16);
		return QStyledItemDelegate::displayText(value, locale);
	}
};
 
MainWindow::MainWindow(QWidget *parent)
    : QMainWindow(parent), ui(new Ui::MainWindow)
{
    ui->setupUi(this);
	m_model = new QStandardItemModel(this);
	QStandardItem *item = new QStandardItem;
	item->setData(3.8133400354, Qt::DisplayRole);
	m_model->appendRow(QList<QStandardItem *>() << item << new QStandardItem("text a"));
	item = new QStandardItem;
	item->setData(2.123003885, Qt::DisplayRole);
	m_model->appendRow(QList<QStandardItem *>() << item << new QStandardItem("text h"));
	item = new QStandardItem;
	item->setData(2.123003876, Qt::DisplayRole);
	m_model->appendRow(QList<QStandardItem *>() << item << new QStandardItem("text c"));
	item = new QStandardItem;
	item->setData(123.85934000053, Qt::DisplayRole);
	m_model->appendRow(QList<QStandardItem *>() << item << new QStandardItem("text a"));
	item = new QStandardItem;
	item->setData(13.85942403234, Qt::DisplayRole);
	m_model->appendRow(QList<QStandardItem *>() << item << new QStandardItem("text f"));
	item = new QStandardItem;
	item->setData(46.8593400354, Qt::DisplayRole);
	m_model->appendRow(QList<QStandardItem *>() << item << new QStandardItem("text g"));
	item = new QStandardItem;
	item->setData(3.2452334, Qt::DisplayRole);
	m_model->appendRow(QList<QStandardItem *>() << item << new QStandardItem("text d"));
	item = new QStandardItem;
	item->setData(8.4223400354, Qt::DisplayRole);
	m_model->appendRow(QList<QStandardItem *>() << item << new QStandardItem("text e"));
	ui->tableView->setModel(m_model);
	ui->tableView->setItemDelegate(new MyDelegate(this));
}
 
MainWindow::~MainWindow()
{
    delete ui;
}

#include "mainwindow.h"
#include "ui_mainwindow.h"

#include <QStyledItemDelegate>

class MyDelegate : public QStyledItemDelegate
{
public:
	MyDelegate(QObject *parent = 0) : QStyledItemDelegate(parent) { }
	QString displayText(const QVariant &value, const QLocale &locale) const {
		if (value.type() == QVariant::Double) return locale.toString(value.toDouble(), 'g', 16);
		return QStyledItemDelegate::displayText(value, locale);
	}
};

MainWindow::MainWindow(QWidget *parent)
    : QMainWindow(parent), ui(new Ui::MainWindow)
{
    ui->setupUi(this);
	m_model = new QStandardItemModel(this);
	QStandardItem *item = new QStandardItem;
	item->setData(3.8133400354, Qt::DisplayRole);
	m_model->appendRow(QList<QStandardItem *>() << item << new QStandardItem("text a"));
	item = new QStandardItem;
	item->setData(2.123003885, Qt::DisplayRole);
	m_model->appendRow(QList<QStandardItem *>() << item << new QStandardItem("text h"));
	item = new QStandardItem;
	item->setData(2.123003876, Qt::DisplayRole);
	m_model->appendRow(QList<QStandardItem *>() << item << new QStandardItem("text c"));
	item = new QStandardItem;
	item->setData(123.85934000053, Qt::DisplayRole);
	m_model->appendRow(QList<QStandardItem *>() << item << new QStandardItem("text a"));
	item = new QStandardItem;
	item->setData(13.85942403234, Qt::DisplayRole);
	m_model->appendRow(QList<QStandardItem *>() << item << new QStandardItem("text f"));
	item = new QStandardItem;
	item->setData(46.8593400354, Qt::DisplayRole);
	m_model->appendRow(QList<QStandardItem *>() << item << new QStandardItem("text g"));
	item = new QStandardItem;
	item->setData(3.2452334, Qt::DisplayRole);
	m_model->appendRow(QList<QStandardItem *>() << item << new QStandardItem("text d"));
	item = new QStandardItem;
	item->setData(8.4223400354, Qt::DisplayRole);
	m_model->appendRow(QList<QStandardItem *>() << item << new QStandardItem("text e"));
	ui->tableView->setModel(m_model);
	ui->tableView->setItemDelegate(new MyDelegate(this));
}

MainWindow::~MainWindow()
{
    delete ui;
}

To copy to clipboard, switch view to plain text mode 

[nikhilqt]

It worked. It took little more time to get hang on it. sorry for that. I made wrong in overriding the displayText() method. My new signature of the method acted as overloaded method of that and the call for that displaytext() did not happen until i realize the mistake.

Thanks for the patience.