set the validation for LineEdit

[sangee]

I used keyboard design in my program.I want to set the values 18.5 to 39.0 only for keyboard's LineEdit.how to set the validation for this LineEdit?

[Naahmi]

I used keyboard design in my program.I want to set the values 18.5 to 39.0 only for keyboard's LineEdit.how to set the validation for this LineEdit?

Here is a small Example: http://www.java2s.com/Code/Cpp/Qt/QDoubleValidatorandQLineEdit.htm

Use QdoubleValidator.

[spirit]

Or this (http://qt-project.org/doc/qt-4.8/widgets-lineedits.html) and this (http://qt-project.org/doc/qt-4.8/widgets-spinboxes.html).

[sangee]

I was already saw this program.but doesn't work it.QDoubleValidator consider for decimal point only not ranges(18.5 to 39.0).how i set the validation for this LineEdit.

[ChrisW67]

QDoubleValidator checks the ranges. As documented, the line edit will not emit QLineEdit::editingFinished() or returnPressed() for invalid (in this case out-of-range) values. At any time QLineEdit::hasAcceptableInput() will return the current acceptability of the value. The validator does not stop you moving focus from the line edit with an intermediate value.

Since you clearly will not believe us, run this program and try 18.4, 18.6, 39.0 and 40 followed by Tab or Return in the top edit box and watch the output.


#include <QtGui>
#include <QDebug>

class Widget: public QWidget
{
Q_OBJECT
QLineEdit *line1;
public:
Widget(): QWidget() {
line1 = new QLineEdit(this);
QDoubleValidator *v = new QDoubleValidator(18.5, 39.0, 1, line1);
v->setNotation(QDoubleValidator::StandardNotation);
line1->setValidator(v);

QDoubleSpinBox *spin = new QDoubleSpinBox(this);
spin->setDecimals(1);
spin->setMinimum(18.0);
spin->setMaximum(39.0);


QVBoxLayout *layout = new QVBoxLayout(this);
layout->addWidget(line1);
layout->addWidget(spin);
setLayout(layout);

connect(line1, SIGNAL(textChanged(QString)), SLOT(slotTextChanged(QString)));
connect(line1, SIGNAL(returnPressed()), SLOT(checkIsValid()));
connect(line1, SIGNAL(editingFinished()), SLOT(checkIsValid()));
}

public slots:
void slotTextChanged(const QString &text) {
qDebug() << "Text changed to" << text << "and value is valid ==" << line1->hasAcceptableInput();
}
void checkIsValid() {
qDebug() << "Edit finished and value is valid ==" << line1->hasAcceptableInput();
}
};

int main(int argc, char **argv)
{
QApplication app(argc, argv);
Widget w;
w.show();
return app.exec();
}
#include "main.moc"


What you really want is a QDoubleSpinBox which is more restrictive, just as easily edited, and always has a valid value.

[sangee]

Thank u very much.