QT中的table View控件显示数据的时候怎么改变显示小数点位数，我想让它可以保存小数点后六位。请大神们帮助帮助。急急急！！！

现在只显示这些，如果手动填写只能填到小数点后两位，怎么修改，我想让他显示小数点后六位，请各位大神帮帮。

这样不就行了

NSString *message = [NSString stringWithFormat:@"%.6f", floatValue];

用自定义委托
.h

#ifndef DELEGATE_H
#define DELEGATE_H

#include <QStyledItemDelegate>

//! [0]
class SpinBoxDelegate : public QStyledItemDelegate
{
    Q_OBJECT

public:
    SpinBoxDelegate(QObject *parent = 0);

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

    void setEditorData(QWidget *editor, const QModelIndex &index) const Q_DECL_OVERRIDE;
    //void setDecimals(QWidget *editor) const Q_DECL_OVERRIDE;
    void setModelData(QWidget *editor, QAbstractItemModel *model, const QModelIndex &index) const Q_DECL_OVERRIDE;

    void updateEditorGeometry(QWidget *editor, const QStyleOptionViewItem &option, const QModelIndex &index) const Q_DECL_OVERRIDE;
};
//! [0]

#endif

.cpp

#include "delegate.h"

#include <QDoubleSpinBox>

//! [0]
SpinBoxDelegate::SpinBoxDelegate(QObject *parent)
    : QStyledItemDelegate(parent)
{
}
//! [0]

//! [1]
QWidget *SpinBoxDelegate::createEditor(QWidget *parent,
    const QStyleOptionViewItem &/* option */,
    const QModelIndex &/* index */) const
{
    QDoubleSpinBox *editor = new QDoubleSpinBox(parent);

    editor->setDecimals(6);//设置小数位数

    return editor;
}
//! [1]

//! [2]
void SpinBoxDelegate::setEditorData(QWidget *editor,
                                    const QModelIndex &index) const
{
    double value = index.model()->data(index, Qt::EditRole).toDouble();

    QDoubleSpinBox *spinBox = static_cast<QDoubleSpinBox*>(editor);
    spinBox->setValue(value);
}
//! [2]

//! [3]
void SpinBoxDelegate::setModelData(QWidget *editor, QAbstractItemModel *model,
                                   const QModelIndex &index) const
{
    QDoubleSpinBox *spinBox = static_cast<QDoubleSpinBox*>(editor);

    spinBox->interpretText();
    double value = spinBox->value();

    model->setData(index, value, Qt::EditRole);
}
//! [3]

//! [4]
void SpinBoxDelegate::updateEditorGeometry(QWidget *editor,
    const QStyleOptionViewItem &option, const QModelIndex &/* index */) const
{
    editor->setGeometry(option.rect);
}
//! [4]

main

#include "delegate.h"

#include <QApplication>
#include <QHeaderView>
#include <QStandardItemModel>
#include <QTableView>

//! [0]
int main(int argc, char *argv[])
{
    QApplication app(argc, argv);

    QStandardItemModel model(4, 2);
    QTableView tableView;
    tableView.setModel(&model);

    SpinBoxDelegate delegate;
    //tableView.setItemDelegate(&delegate);
    tableView.setItemDelegateForColumn(1, &delegate);
//! [0]

    tableView.horizontalHeader()->setStretchLastSection(true);

//! [1]
    for (int row = 0; row < 4; ++row) {
        for (int column = 0; column < 2; ++column) {
            QModelIndex index = model.index(row, column, QModelIndex());
            model.setData(index, QVariant((double(row) + 1.111111) * (double(column) + 1.111111)));
        }
//! [1] //! [2]
    }
//! [2]

//! [3]
    tableView.setWindowTitle(QObject::tr("Spin Box Delegate"));
    tableView.show();
    return app.exec();
}
//! [3]