qmltypereference.qdoc

Go to the documentation of this file.

// Copyright (C) 2017 The Qt Company Ltd.
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR GFDL-1.3-no-invariants-only
 
/*!
\qmlmodule QtQml
\title Qt QML QML Types
\ingroup qmlmodules
\brief List of QML types provided by the Qt QML module
 
The \l{Qt Qml} module provides the definition and implementation of various
convenience types that can be used with the QML language. This includes
elementary QML types, which can provide the basis for further extensions to the
QML language. The \l QtObject and \l Component object types are non-visual and
provide building-blocks for extensions to QML.
 
\section1 Importing QtQml
 
The types provided by the \c QtQml module are only available in a QML document
if that document imports the \c QtQml namespace (or if the document imports the
\c QtQuick namespace, as noted below).
 
To use the module, import the \c QtQml module with the following statement:
 
\qml
import QtQml
\endqml
 
Many clients will never need to use the \c QtQml module directly, but will rather
import it indirectly via the \c QtQuick module as follows:
 
\qml
import QtQuick
\endqml
 
See the \l{Qt Quick} module documentation for more information about its types.
 
The QML types for creating lists and models, such as \l ListModel and
\l ListElement, belong to a submodule, \l{Qt QML Models QML Types}{QtQml.Models}.
 
The \l WorkerScript QML type belongs to the submodule
\l{Qt QML WorkerScript QML Types}{QtQml.WorkerScript}.
 
Both, \l{Qt QML Models QML Types}{QtQml.Models} and
\l{Qt QML WorkerScript QML Types}{QtQml.WorkerScript} are automatically imported
whenever you import \c QtQml. All their types are then available, too.
 
The \l{Qt Quick} module automatically imports \c QtQml and, transitively,
\l{Qt QML Models QML Types}{QtQml.Models} and
\l{Qt QML WorkerScript QML Types}{QtQml.WorkerScript}, making all their types
available whenever you import \c QtQuick.
 
\section1 Value Types
 
The following \l{qtqml-typesystem-valuetypes.html}{QML Value Types} are
provided:
 
\annotatedlist qtqmlvaluetypes
 
\section1 Sequence Types
 
The following \l{QML Sequence Types}{QML sequence types} are provided by the Qt
QML module in addition to the ones registered with each value type and object
type:
 
\list
  \li \c {std::vector<QString>}
  \li \c {std::vector<QUrl>}
  \li \c {std::vector<bool>}
  \li \c {std::vector<int>}
  \li \c {std::vector<float>}
  \li \c {std::vector<double>}
\endlist
 
\section1 Object Types
 
The following \l{qtqml-typesystem-objecttypes.html}{QML object types} are
provided:
 
*/
 
/*!
\qmlvaluetype date
\ingroup qmlvaluetypes
\brief a date value.
 
The \c date type refers to a date value, including the time of the day.
 
Properties of type \c date default to an invalid value.
 
To create a \c date value, specify it as a "YYYY-MM-DDThh:mm:ss.zzzZ" string.
(The T is literal, YYYY is a full year number, MM and DD are month and day
numbers, hh, mm and ss are hours, minutes and seconds, with .zzz as
milliseconds and Z as time-zone offset. The T and following time are optional.
If they are omitted, the date is handled as the start of UTC's day, which
falls on other dates in some time-zones. When T is included, the :ss.zzz or
just .zzz part can be omitted. With or without those, the zone offset can be
omitted, in which case local time is used.) For example:
 
\qml
MyDatePicker { minDate: "2000-01-01 0:0"; maxDate: "2020-12-31 23:59" }
\endqml
 
To read a date value returned from a C++ extension class, use
\l{QtQml::Qt::formatDate()}{Qt.formatDate()} and \l{QtQml::Qt::formatDateTime()}{Qt.formatDateTime()}.
 
When integrating with C++, note that any QDate or QDateTime value
\l{qtqml-cppintegration-data.html}{passed into QML from C++} is automatically
converted into a \c date value, and vice-versa. Note, however, that
converting a QDate will result in UTC's start of the day, which falls on
a different date in some other time-zones. It is usually more robust
to convert the QDate via a QDateTime explicitly, specifying local-time
or a relevant time-zone and selecting a time of day (such as noon)
that reliably exists (daylight-savings transitions skip an hour, near
one end or the other of a day).
 
This value type is provided by the QML language. It can be implicitly converted
to a \l{QtQml::Date}{Date} object.
 
\sa {QtQml::Date}{QML Date object}, {QML Value Types}
*/
 
/*!
\qmlvaluetype point
\ingroup qtqmlvaluetypes
\brief a value with x and y attributes.
 
The \c point type refers to a value with \c x and \c y attributes.
 
To create a \c point value, specify it as a "x,y" string:
 
\qml
CustomObject { myPointProperty: "0,20" }
\endqml
 
Or use the \l{QtQml::Qt::point()}{Qt.point()} function:
 
\qml
CustomObject { myPointProperty: Qt.point(0, 20) }
\endqml
 
When integrating with C++, note that any QPoint or QPointF value
\l{qtqml-cppintegration-data.html}{passed into QML from C++} is automatically
converted into a \c point value. When a \c point value is passed to C++, it
is automatically converted into a QPointF value.
 
Properties of type \c point are \c {Qt.point(0, 0)} by default.
 
\sa{QML Value Types}
*/
 
/*!
\qmlvaluetype size
\ingroup qtqmlvaluetypes
\brief a value with width and height attributes.
 
The \c size type refers to a value with has \c width and \c height attributes.
 
Properties of type \c size have \c {Qt.size(-1, -1)} as default value.
 
For example, to read the \c width and \c height values of the
\l {Image::sourceSize} size-type property:
 
\qml
Column {
    Image { id: image; source: "logo.png" }
    Text { text: image.sourceSize.width + "," + image.sourceSize.height }
}
\endqml
 
To create a \c size value, specify it as a "width x height" string:
 
\qml
Image { sourceSize: "150x50" }
\endqml
 
Or use the \l{QtQml::Qt::size()}{Qt.size()} function:
 
\qml
Image { sourceSize: Qt.size(150, 50) }
\endqml
 
When integrating with C++, note that any QSize or QSizeF value
\l{qtqml-cppintegration-data.html}{passed into QML from C++} is automatically
converted into a \c size value, and vice-versa. When a \c size value is passed to C++, it
is automatically converted into a QSizeF value.
 
\sa{QML Value Types}
*/
 
/*!
\qmlvaluetype rect
\ingroup qtqmlvaluetypes
\brief a value with x, y, width and height attributes.
 
The \c rect type refers to a value with \c x, \c y, \c width and \c height attributes.
 
Properties of type \c rect are \c {Qt.rect(0, 0, 0, 0)} by default. This is an
empty rectangle at the coordinate origin.
 
For example, to read the \c width and \c height values of the \l Item
\l {Item::childrenRect.x}{childrenRect} rect-type property:
 
\qml
Rectangle {
    width: childrenRect.width
    height: childrenRect.height
 
    Rectangle { width: 100; height: 100 }
}
\endqml
 
To create a \c rect value, specify it as a "x, y, width x height" string:
 
\qml
CustomObject { myRectProperty: "50,50,100x100" }
\endqml
 
Or use the \l{QtQml::Qt::rect()}{Qt.rect()} function:
 
\qml
CustomObject { myRectProperty: Qt.rect(50, 50, 100, 100) }
\endqml
 
The \c rect type also exposes read-only \c left, \c right, \c top and \c bottom
attributes. These are the same as their \l {QRectF}{C++ counterparts}.
 
When integrating with C++, note that any QRect or QRectF value
\l{qtqml-cppintegration-data.html}{passed into QML from C++} is automatically
converted into a \c rect value, and vice-versa. When a \c rect value is passed to C++, it
is automatically converted into a QRectF value.
 
\sa{QML Value Types}
*/