QVariant Class Reference
[QtCore module]

QVariant::QVariant ()

Constructs an invalid variant.

QVariant::QVariant ( const QLocale & l )

Constructs a new variant with a locale value, l.

QVariant::QVariant ( const QRegExp & regExp )

Constructs a new variant with the regexp value regExp.

QVariant::QVariant ( Qt::GlobalColor color )

Constructs a new variant of type QVariant::Color and initializes it with color.

This is a convenience constructor that allows QVariant(Qt::blue); to create a valid QVariant storing a QColor.

Note: This constructor will assert if the application does not link to the Qt GUI library.

This function was introduced in Qt 4.2.

QVariant::QVariant ( Type type )

Constructs a null variant of type type.

QVariant::QVariant ( int typeOrUserType, const void * copy )

Constructs variant of type typeOrUserType, and initializes with copy if copy is not 0.

Note that you have to pass the address of the variable you want stored.

Usually, you never have to use this constructor, use qVariantFromValue() instead to construct variants from the pointer types represented by QMetaType::VoidStar, QMetaType::QObjectStar and QMetaType::QWidgetStar.

See also qVariantFromValue() and Type.

QVariant::QVariant ( const QVariant & p )

Constructs a copy of the variant, p, passed as the argument to this constructor.

QVariant::QVariant ( QDataStream & s )

Reads the variant from the data stream, s.

QVariant::QVariant ( int val )

Constructs a new variant with an integer value, val.

QVariant::QVariant ( uint val )

Constructs a new variant with an unsigned integer value, val.

QVariant::QVariant ( qlonglong val )

Constructs a new variant with a long long integer value, val.

QVariant::QVariant ( qulonglong val )

Constructs a new variant with an unsigned long long integer value, val.

QVariant::QVariant ( bool val )

Constructs a new variant with a boolean value, val.

QVariant::QVariant ( double val )

Constructs a new variant with a floating point value, val.

QVariant::QVariant ( float val )

Constructs a new variant with a floating point value, val.

This function was introduced in Qt 4.6.

QVariant::QVariant ( const char * val )

Constructs a new variant with a string value of val. The variant creates a deep copy of val, using the encoding set by QTextCodec::setCodecForCStrings().

Note that val is converted to a QString for storing in the variant and QVariant::type() will return QMetaType::QString for the variant.

You can disable this operator by defining QT_NO_CAST_FROM_ASCII when you compile your applications.

See also QTextCodec::setCodecForCStrings().

QVariant::QVariant ( const QByteArray & val )

Constructs a new variant with a bytearray value, val.

QVariant::QVariant ( const QBitArray & val )

Constructs a new variant with a bitarray value, val.

QVariant::QVariant ( const QString & val )

Constructs a new variant with a string value, val.

QVariant::QVariant ( const QLatin1String & val )

Constructs a new variant with a string value, val.

QVariant::QVariant ( const QStringList & val )

Constructs a new variant with a string list value, val.

QVariant::QVariant ( const QChar & c )

Constructs a new variant with a char value, c.

QVariant::QVariant ( const QDate & val )

Constructs a new variant with a date value, val.

QVariant::QVariant ( const QTime & val )

Constructs a new variant with a time value, val.

QVariant::QVariant ( const QDateTime & val )

Constructs a new variant with a date/time value, val.

QVariant::QVariant ( const QList<QVariant> & val )

Constructs a new variant with a list value, val.

QVariant::QVariant ( const QMap<QString, QVariant> & val )

Constructs a new variant with a map of QVariants, val.

QVariant::QVariant ( const QHash<QString, QVariant> & val )

Constructs a new variant with a hash of QVariants, val.

QVariant::QVariant ( const QSize & val )

Constructs a new variant with a size value of val.

QVariant::QVariant ( const QSizeF & val )

Constructs a new variant with a size value of val.

QVariant::QVariant ( const QPoint & val )

Constructs a new variant with a point value of val.

QVariant::QVariant ( const QPointF & val )

Constructs a new variant with a point value of val.

QVariant::QVariant ( const QLine & val )

Constructs a new variant with a line value of val.

QVariant::QVariant ( const QLineF & val )

Constructs a new variant with a line value of val.

QVariant::QVariant ( const QRect & val )

Constructs a new variant with a rect value of val.

QVariant::QVariant ( const QRectF & val )

Constructs a new variant with a rect value of val.

QVariant::QVariant ( const QUrl & val )

Constructs a new variant with a url value of val.

 QVariant v = 42;

 v.canConvert<int>();              // returns true
 v.canConvert<QString>();          // returns true

 MyCustomStruct s;
 v.setValue(s);

 v.canConvert<int>();              // returns false
 v.canConvert<MyCustomStruct>();   // returns true

 MyCustomStruct s;
 return QVariant::fromValue(s);

 QVariant v;

 v.setValue(5);
 int i = v.toInt();         // i is now 5
 QString s = v.toString()   // s is now "5"

 MyCustomStruct c;
 v.setValue(c);

 ...

 MyCustomStruct c2 = v.value<MyCustomStruct>();

 QVariant v;

 MyCustomStruct c;
 if (v.canConvert<MyCustomStruct>())
     c = v.value<MyCustomStruct>(v);

 v = 7;
 int i = v.value<int>();                        // same as v.toInt()
 QString s = v.value<QString>();                // same as v.toString(), s is now "7"
 MyCustomStruct c2 = v.value<MyCustomStruct>(); // conversion failed, c2 is empty

 QObject *object = getObjectFromSomewhere();
 QVariant data = qVariantFromValue(object);