QLocale Class Reference
[QtCore module]

Detailed Description

The QLocale class converts between numbers and their string representations in various languages.

QLocale is initialized with a language/country pair in its constructor and offers number-to-string and string-to-number conversion functions similar to those in QString.

Example:

 QLocale egyptian(QLocale::Arabic, QLocale::Egypt);
 QString s1 = egyptian.toString(1.571429E+07, 'e');
 QString s2 = egyptian.toString(10);

 double d = egyptian.toDouble(s1);
 int i = egyptian.toInt(s2);

QLocale supports the concept of a default locale, which is determined from the system's locale settings at application startup. The default locale can be changed by calling the static member setDefault(). Setting the default locale has the following effects:

• If a QLocale object is constructed with the default constructor, it will use the default locale's settings.
• QString::toInt(), QString::toDouble(), etc., interpret the string according to the default locale. If this fails, it falls back on the "C" locale.
• QString::arg() uses the default locale to format a number when its position specifier in the format string contains an 'L', e.g. "%L1".

The following example illustrates how to use QLocale directly:

 QLocale::setDefault(QLocale(QLocale::Hebrew, QLocale::Israel));
 QLocale hebrew; // Constructs a default QLocale
 QString s1 = hebrew.toString(15714.3, 'e');

 bool ok;
 double d;

 QLocale::setDefault(QLocale::C);
 d = QString("1234,56").toDouble(&ok);   // ok == false
 d = QString("1234.56").toDouble(&ok);   // ok == true, d == 1234.56

 QLocale::setDefault(QLocale::German);
 d = QString("1234,56").toDouble(&ok);   // ok == true, d == 1234.56
 d = QString("1234.56").toDouble(&ok);   // ok == true, d == 1234.56

 QLocale::setDefault(QLocale(QLocale::English, QLocale::UnitedStates));
 str = QString("%1 %L2 %L3")
       .arg(12345).arg(12345).arg(12345, 0, 16);
 // str == "12345 12,345 3039"

When a language/country pair is specified in the constructor, one of three things can happen:

• If the language/country pair is found in the database, it is used.
• If the language is found but the country is not, or if the country is AnyCountry, the language is used with the most appropriate available country (for example, Germany for German),
• If neither the language nor the country are found, QLocale defaults to the default locale (see setDefault()).

The "C" locale is identical in behavior to English/UnitedStates.

Use language() and country() to determine the actual language and country values used.

An alternative method for constructing a QLocale object is by specifying the locale name.

 QLocale korean("ko");
 QLocale swiss("de_CH");

This constructor converts the locale name to a language/country pair; it does not use the system locale database.

QLocale's data is based on Common Locale Data Repository v1.6.1.

The double-to-string and string-to-double conversion functions are covered by the following licenses:

See also QString::arg(), QString::toInt(), and QString::toDouble().

Member Type Documentation

 bool ok;
 double d;

 QLocale c(QLocale::C);
 d = c.toDouble( "1234.56", &ok );  // ok == true, d == 1234.56
 d = c.toDouble( "1,234.56", &ok ); // ok == true, d == 1234.56
 d = c.toDouble( "1234,56", &ok );  // ok == false

 QLocale german(QLocale::German);
 d = german.toDouble( "1234,56", &ok );  // ok == true, d == 1234.56
 d = german.toDouble( "1.234,56", &ok ); // ok == true, d == 1234.56
 d = german.toDouble( "1234.56", &ok );  // ok == false

 d = german.toDouble( "1.234", &ok );    // ok == true, d == 1234.0