However, note that QVariant types can only be cast when they have had a value set. Qt and respective logos are trademarks of The Qt Company Ltd. Type, and they can be returned by this function. Date , String , Time. Returns the variant as a qreal if the variant has userType QMetaType:: Convert this variant to type QMetaType:: I tried to edit the post but my modification would be less than 6 chars so I couldn’t. The methods named toT e.
If the value is convertible to a QMetaType:: Returns the variant as a QTime if the variant has type Time , DateTime , or String ; otherwise returns an invalid time. Constructs a new variant with a string value of val. UserType had this value in Qt4. QVariant QChar c Constructs a new variant with a char value, c. This is typically because canConvert only reports the general ability of QVariant to convert between types given suitable data; it is still possible to supply data which cannot actually be converted. Note that subclasses that reimplement clear should reimplement the destructor to call clear.
It is possible to iterate over the contents of the container without extracting it as a copied QVariantHash or QVariantMap:.
Some type s are multi-valued, for example a string list. Transform correspond to the values in the ranges QMetaType.
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If ok is non-null: However, if the string contains non-numeric characters, it cannot be converted to t integer, and any attempt to convert it will fail. QVariantMap; otherwise returns an empty map. Returns the variant as a Qvaroant if the variant has type BitArray ; otherwise returns an empty bit array. Data contains long long, and long double is the biggest standard type. The result of the function is not affected by the result of QVariant:: QSize; otherwise returns an invalid QSize.
Returns the stored value converted to the template type T. Font 64 a QFont QVariant. Int 2 an int QVariant.
QVariant Class Reference
Without QVariant, this would be a problem for QObject:: Qvwriant function was introduced in Qt 4. Converts the int representation of the storage type, typeIdto its string representation. Typeand they can be returned by this function. The QVariant class acts like a union for the most common Qt data types.
This operation is very fast and never fails. This function was introduced in Qt 5.
Comparability might not be availabe for the type stored in this QVariant or in v. Call qRegisterMetaType to make type available to non-template based functions, such as the queued signal and slot connections. The QVariant class acts like a union for the most common Qt data types. QStringan invalid time will be returned if the string cannot be parsed as a Qt:: QVariant QChar qvariznt Constructs a new variant with a char value, c.
Returns the variant as a double if the variant has type DoubleQMetaType. For example, canConvert Int would return true when called on a variant containing a string because, in principle, QVariant is able to convert strings of numbers to integers.
Ro bool val Constructs fo new variant with a boolean value, val. Polygon 71 a QPolygon QVariant.
UInt 3 a uint QVariant. For historical reasons, converting a null QVariant results in a null value of the desired type e. Charwhich is the same as QMetaType. If v1 and v2 have the qvariqnt typethe type’s equality operator is used qvaruant comparison. UserType had this yo in Qt4. UserType Base value for user-defined types. This is very powerful and versatile, but may prove less memory and speed efficient than storing specific types in standard data structures.
However, note that QVariant types can only be cast when they have had a value set. Returns true if the storage type of this variant is not QVariant. QVariant Type type Constructs a null variant of type type. In this tutorial, we will learn about QVariant. Invalid or doesn’t exist. ULongLong ; otherwise returns 0. Pen 77 a QPen QVariant.
QLocale ; otherwise returns an invalid QLocale. Bitmap 73 a QBitmap QVariant. Originally Posted by tonnot. Without QVariantthis would be a problem for QObject::