QLineEdit set min max range?

[jacek]

Then use QDoubleValidator or QRegExpValidator (regexp should be something like "(?:1[0-5]|[1-9])(?:[.,]\\d\\d?)?|16(?:[.,]00?)?").

[whitefurrows]

Hi,

that's great your regexp work fine. I read the doc for QRegExp but i dont know what you do. Can you describe how your regexp work and i understand that. The problem is i have many other ranges to set e.g. 0-50, 15-32, 65-105 and i can't change your regexp.

How can i set a QDoubleValidator its's easey, but my code don't work. I can set values out of range. Why?

lineEdit->setValidator(new QDoubleValidator( 1.00, 16.00, 2, lineEdit));

lineEdit->setValidator(new QDoubleValidator( 1.00, 16.00, 2, lineEdit));

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Greetings,

Whitefurrows

[jacek]

Can you describe how your regexp work and i understand that. The problem is i have many other ranges to set e.g. 0-50, 15-32, 65-105 and i can't change your regexp.

In such case, IMO, it would be better if you create your own validator class, because regexps aren't very readable.

Anyway, suppose you want a regexp for 65-105 range. Valid numbers are:
65, 66, 67, 68, 69, 70, ..., 79, 80, ..., 89, 90, ..., 99, 100, 101, 102, 103, 104, 105

There are three possibilities:

• 6 and one of {5, 6, 7, 8, 9} -> 6[5-9]
• one of {7, 8, 9} and a digit -> [7-9]\\d
• 10 and one of {0, 1, 2, 3, 4, 5} -> 10[0-5]

and you just have to join them: 6[5-9]|[7-9]\\d|10[0-5]

How can i set a QDoubleValidator its's easey, but my code don't work. I can set values out of range. Why?

Because you can enter 1500.00e-2, which is a valid number.

[whitefurrows]

OK i have understand how work the regexp, thank you.

I think really it's better to write my own validator class.

class myDoubleValidator : public QDoubleValidator
{
public:
myDoubleValidator( double bottom, double top, int decimals, QObject* parent = 0)
: QDoubleValidator( bottom, top, decimals, parent){}
 
QValidator::State validate ( QString & input, int &pos ) const
{
if ( input.isEmpty() || input == "." )
return Intermediate;
//I'm not sure what can i do here
return Invalid;
}
 
return Acceptable;
}
};

class myDoubleValidator : public QDoubleValidator
{
public:
myDoubleValidator( double bottom, double top, int decimals, QObject* parent = 0)
: QDoubleValidator( bottom, top, decimals, parent){}

QValidator::State validate ( QString & input, int &pos ) const
{
if ( input.isEmpty() || input == "." )
return Intermediate;
//I'm not sure what can i do here
return Invalid;
}

return Acceptable;
}
};

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Can you help me please?

[jacek]

Take a look at QDoubleValidator::validate() implementation (it's in %QTDIR%/src/gui/widgets/qvalidator.cpp). All you have to do is to remove the part that handles the exponent.

[whitefurrows]

I don't want change orginal files. I try this:

class MyDoubleValidator : public QDoubleValidator
{
public:
	MyDoubleValidator( double bottom, double top, int decimals, QObject* parent = 0)
		: QDoubleValidator( bottom, top, decimals, parent)
	{}
 
	QValidator::State QDoubleValidator::validate(QString & input, int &) const
	{
		QRegExp empty(QString::fromLatin1("-?\\.?"));
		if (input.contains(' '))
			return Invalid;
		if (b >= 0 && input.startsWith(QLatin1Char('-')))
			return Invalid;
		if (empty.exactMatch(input))
			return Intermediate;
		bool ok = true;
		double entered = input.toDouble(&ok);
		int nume = input.count('e', Qt::CaseInsensitive);
		if (!ok) {
			// explicit exponent regexp
			QRegExp expexpexp(QString::fromLatin1("[Ee][+-]?(\\d*)$"));
			int eePos = expexpexp.indexIn(input);
			if (eePos > 0 && nume == 1) {
				QString mantissa = input.left(eePos);
				entered = mantissa.toDouble(&ok);
				if (!ok)
					return Invalid;
				if (expexpexp.cap(1).isEmpty())
					return Intermediate;
			} else if (eePos == 0) {
				return Intermediate;
			} else {
				return Invalid;
			}
		}
 
		int i = input.indexOf('.');
		if (i >= 0 && nume == 0) {
			// has decimal point (but no E), now count digits after that
			i++;
			int j = i;
			while(input[j].isDigit())
				j++;
			if (j - i > d)
				return Intermediate;
		}
 
		if (entered < b || entered > t)
			return Intermediate;
		return Acceptable;
	}
};

class MyDoubleValidator : public QDoubleValidator
{
public:
	MyDoubleValidator( double bottom, double top, int decimals, QObject* parent = 0)
		: QDoubleValidator( bottom, top, decimals, parent)
	{}

	QValidator::State QDoubleValidator::validate(QString & input, int &) const
	{
		QRegExp empty(QString::fromLatin1("-?\\.?"));
		if (input.contains(' '))
			return Invalid;
		if (b >= 0 && input.startsWith(QLatin1Char('-')))
			return Invalid;
		if (empty.exactMatch(input))
			return Intermediate;
		bool ok = true;
		double entered = input.toDouble(&ok);
		int nume = input.count('e', Qt::CaseInsensitive);
		if (!ok) {
			// explicit exponent regexp
			QRegExp expexpexp(QString::fromLatin1("[Ee][+-]?(\\d*)$"));
			int eePos = expexpexp.indexIn(input);
			if (eePos > 0 && nume == 1) {
				QString mantissa = input.left(eePos);
				entered = mantissa.toDouble(&ok);
				if (!ok)
					return Invalid;
				if (expexpexp.cap(1).isEmpty())
					return Intermediate;
			} else if (eePos == 0) {
				return Intermediate;
			} else {
				return Invalid;
			}
		}

		int i = input.indexOf('.');
		if (i >= 0 && nume == 0) {
			// has decimal point (but no E), now count digits after that
			i++;
			int j = i;
			while(input[j].isDigit())
				j++;
			if (j - i > d)
				return Intermediate;
		}

		if (entered < b || entered > t)
			return Intermediate;
		return Acceptable;
	}
};

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but i can't compile!

[jacek]

I try this:

You're on the right track.

It should be:

class MyDoubleValidator : public QDoubleValidator
{
public:
	MyDoubleValidator( double bottom, double top, int decimals, QObject* parent = 0)
		: QDoubleValidator( bottom, top, decimals, parent)
	{}
 
	QValidator::State validate(QString & input, int &) const
	{
		// we don't have the access to private members of QDoubleValidator, 
		// so we must simulate them:
		const double b = bottom();
		const double t = top();
		const int d = decimals();
 
		QRegExp empty(QString::fromLatin1("-?\\.?"));
		if (input.contains(' '))
			return Invalid;
		...
	}
};

class MyDoubleValidator : public QDoubleValidator
{
public:
	MyDoubleValidator( double bottom, double top, int decimals, QObject* parent = 0)
		: QDoubleValidator( bottom, top, decimals, parent)
	{}

	QValidator::State validate(QString & input, int &) const
	{
		// we don't have the access to private members of QDoubleValidator, 
		// so we must simulate them:
		const double b = bottom();
		const double t = top();
		const int d = decimals();

		QRegExp empty(QString::fromLatin1("-?\\.?"));
		if (input.contains(' '))
			return Invalid;
		...
	}
};

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[whitefurrows]

Hi,

that's work fine. Thank you for your great help.

Greetings,

Whitefurrows

[whitefurrows]

Hi,

sorry i have trouble with my own QDoubleValidator, i set a Range 5-25 but i can't type 15 in to the QLineEdit:
myLineEdit->setValidator(new MyDoubleValidator( 5, 25, 2, myLineEdit));

Can anybody help me?

Greetings,

Whitefurrows

class MyDoubleValidator : public QDoubleValidator
{
public:
	MyDoubleValidator( double bottom, double top, int decimals, QObject* parent = 0)
		: QDoubleValidator( bottom, top, decimals, parent){}
 
	QValidator::State validate(QString & input, int &) const
	{
		const double b = bottom();
		const double t = top();
		const int d = decimals();
 
		QRegExp empty(QString::fromLatin1("-?\\.?"));
		if (input.contains(' '))
			return Invalid;
		if (b >= 0 && input.startsWith(QLatin1Char('-')))
			return Invalid;
		if (empty.exactMatch(input))
			return Intermediate;
 
		bool ok = false;
		double entered = input.toDouble(&ok);
		if (!ok) return Invalid;
 
		int nume = input.count('e', Qt::CaseInsensitive);
 
		int i; 
		if (input.contains(','))
			i = input.indexOf(',');
		else
			i = input.indexOf('.');
 
		if (i >= 0 && nume == 0) {
			i++;
			int j = i;
			while(input[j].isDigit())
				j++;
			if (j - i > d)
				return Invalid;
		}
 
		if (entered < b || entered > t)
			return Invalid;
 
		return Acceptable;			
	}
};

class MyDoubleValidator : public QDoubleValidator
{
public:
	MyDoubleValidator( double bottom, double top, int decimals, QObject* parent = 0)
		: QDoubleValidator( bottom, top, decimals, parent){}
 
	QValidator::State validate(QString & input, int &) const
	{
		const double b = bottom();
		const double t = top();
		const int d = decimals();

		QRegExp empty(QString::fromLatin1("-?\\.?"));
		if (input.contains(' '))
			return Invalid;
		if (b >= 0 && input.startsWith(QLatin1Char('-')))
			return Invalid;
		if (empty.exactMatch(input))
			return Intermediate;

		bool ok = false;
		double entered = input.toDouble(&ok);
		if (!ok) return Invalid;

		int nume = input.count('e', Qt::CaseInsensitive);

		int i; 
		if (input.contains(','))
			i = input.indexOf(',');
		else
			i = input.indexOf('.');
	
		if (i >= 0 && nume == 0) {
			i++;
			int j = i;
			while(input[j].isDigit())
				j++;
			if (j - i > d)
				return Invalid;
		}

		if (entered < b || entered > t)
			return Invalid;

		return Acceptable;			
	}
};

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[jacek]

The problem is here:

if (entered < b || entered > t)
			return Invalid;

if (entered < b || entered > t)
			return Invalid;

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If the allowed range is 5--25, then "1" should be an intermediate value, not invalid one.
It should be probably:

if( entered < b ) {
   return Intermediate;
}
else if( entered > t ) {
   return Invalid;
}

if( entered < b ) {
   return Intermediate;
}
else if( entered > t ) {
   return Invalid;
}

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[whitefurrows]

Hi,

sorry i don't have get a notification. That's right, but the user can put wrong values to the QLineEdit.

What can i do?

Greetings,

Whitefurrows

[jacek]

That's right, but the user can put wrong values to the QLineEdit.

The problem is that line edit can loose focus when it contains an intermediate value. IMO you should ask the Trolls whether this is a correct behavior.