String length limited in QTableWidgetItem

[Lykurg]

Internal QTableWidget uses a model, so you could consider making your own model so that you can keep control. But to your problem: One way I think of right now is to set a custom delegate via QAbstractItemView::setItemDelegate(). In there you define the editor widget (which defines the limit of characters). This way the focus wont be a problem.
Or you can also have a look at QItemEditorFactory (but I have never worked with that, so I don't exactly know if it could fit your needs.)

[joseprl89]

Thanks for your advice, now it works perfectly without strange behaviours, if someone has the same problem, here comes the code of the delegate:

*.h

#ifndef STRINGDELEGATE_H
#define STRINGDELEGATE_H
 
#include <QItemDelegate>
#include <QLineEdit>
class stringDelegate : public QItemDelegate
{
    Q_OBJECT
public:
    explicit stringDelegate(int length, QObject *parent = 0);
    QWidget *createEditor(QWidget *parent, const QStyleOptionViewItem &option,const QModelIndex &index) const;
 
signals:
 
public slots:
    void commitAndCloseEditor();
 
private:
    int length;
};
 
#endif // STRINGDELEGATE_H

#ifndef STRINGDELEGATE_H
#define STRINGDELEGATE_H

#include <QItemDelegate>
#include <QLineEdit>
class stringDelegate : public QItemDelegate
{
    Q_OBJECT
public:
    explicit stringDelegate(int length, QObject *parent = 0);
    QWidget *createEditor(QWidget *parent, const QStyleOptionViewItem &option,const QModelIndex &index) const;

signals:

public slots:
    void commitAndCloseEditor();

private:
    int length;
};

#endif // STRINGDELEGATE_H

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*.cpp

#include "stringdelegate.h"
 
stringDelegate::stringDelegate(int length, QObject *parent) :
    QItemDelegate(parent)
{
    this->length=length;
}
 
QWidget* stringDelegate::createEditor(QWidget *parent, const QStyleOptionViewItem &/*option*/,const QModelIndex &/*index*/  ) const{
    QLineEdit *line = new QLineEdit(parent);
    line->setMaxLength(length);
    line->setFrame(false);
    connect(line, SIGNAL(editingFinished()),this, SLOT(commitAndCloseEditor()));
    return line;
}
 
void stringDelegate::commitAndCloseEditor(){
    QLineEdit *editor = qobject_cast<QLineEdit *>(sender());
    emit commitData(editor);
    emit closeEditor(editor);
}

#include "stringdelegate.h"

stringDelegate::stringDelegate(int length, QObject *parent) :
    QItemDelegate(parent)
{
    this->length=length;
}

QWidget* stringDelegate::createEditor(QWidget *parent, const QStyleOptionViewItem &/*option*/,const QModelIndex &/*index*/  ) const{
    QLineEdit *line = new QLineEdit(parent);
    line->setMaxLength(length);
    line->setFrame(false);
    connect(line, SIGNAL(editingFinished()),this, SLOT(commitAndCloseEditor()));
    return line;
}

void stringDelegate::commitAndCloseEditor(){
    QLineEdit *editor = qobject_cast<QLineEdit *>(sender());
    emit commitData(editor);
    emit closeEditor(editor);
}

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[grantbj74]

Hi,

I have seen the following code in a few examples. Is it needed ? My code seems to work without it.

Thanks in advance, Brendan

line->setFrame(false);
connect(line, SIGNAL(editingFinished()),this, SLOT(commitAndCloseEditor()));
...
...
... 
void stringDelegate::commitAndCloseEditor(){
QLineEdit *editor = qobject_cast<QLineEdit *>(sender());
emit commitData(editor);
emit closeEditor(editor);
}

line->setFrame(false);
connect(line, SIGNAL(editingFinished()),this, SLOT(commitAndCloseEditor()));
...
...
... 
void stringDelegate::commitAndCloseEditor(){
QLineEdit *editor = qobject_cast<QLineEdit *>(sender());
emit commitData(editor);
emit closeEditor(editor);
}

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[rohitkk]

why is it giving the error --> reference to 'connect' is ambiguous?