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Diffstat (limited to 'src/corelib/doc/src/objectmodel/bindableproperties.qdoc')
| -rw-r--r-- | src/corelib/doc/src/objectmodel/bindableproperties.qdoc | 58 |
1 files changed, 31 insertions, 27 deletions
diff --git a/src/corelib/doc/src/objectmodel/bindableproperties.qdoc b/src/corelib/doc/src/objectmodel/bindableproperties.qdoc index 5c9685656a..9b3ea6ae66 100644 --- a/src/corelib/doc/src/objectmodel/bindableproperties.qdoc +++ b/src/corelib/doc/src/objectmodel/bindableproperties.qdoc @@ -1,29 +1,5 @@ -/**************************************************************************** -** -** Copyright (C) 2021 The Qt Company Ltd. -** Contact: https://www.qt.io/licensing/ -** -** This file is part of the documentation of the Qt Toolkit. -** -** $QT_BEGIN_LICENSE:FDL$ -** Commercial License Usage -** Licensees holding valid commercial Qt licenses may use this file in -** accordance with the commercial license agreement provided with the -** Software or, alternatively, in accordance with the terms contained in -** a written agreement between you and The Qt Company. For licensing terms -** and conditions see https://www.qt.io/terms-conditions. For further -** information use the contact form at https://www.qt.io/contact-us. -** -** GNU Free Documentation License Usage -** Alternatively, this file may be used under the terms of the GNU Free -** Documentation License version 1.3 as published by the Free Software -** Foundation and appearing in the file included in the packaging of -** this file. Please review the following information to ensure -** the GNU Free Documentation License version 1.3 requirements -** will be met: https://www.gnu.org/licenses/fdl-1.3.html. -** $QT_END_LICENSE$ -** -****************************************************************************/ +// Copyright (C) 2021 The Qt Company Ltd. +// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR GFDL-1.3-no-invariants-only /*! \page bindableproperties.html @@ -45,6 +21,20 @@ uses the encapsulating QObject to store the pointer to the management data structure. + \section1 Why Use Bindable Properties? + + Property bindings are one of the core features of QML. They allow to specify + relationships between different object properties and automatically update + properties' values whenever their dependencies change. Bindable properties + allow to achieve the same not only in QML code, but also in C++. Using + bindable properties can help to simplify your program, by eliminating a lot + of boilerplate code for tracking and reacting to dependency updates of + different objects. + + The \l {Introductory Example} below demonstrates the usage of bindable + properties in C++ code. You can also check \l {Bindable Properties} example + to see how the bindable properties can help to improve your code. + \section1 Introductory Example The binding expression computes the value by reading other QProperty values. @@ -191,7 +181,7 @@ } \endcode - All the common rules and recomendations regarding writing to bindable + All the common rules and recommendations regarding writing to bindable properties also apply here. As soon as the base class implementation is called, all the observers are notified about the change to the property. This means that class invariants must be met before calling the base @@ -257,4 +247,18 @@ be called for the current value of the property, register your callback using subscribe() instead. + \section1 Interaction with Q_PROPERTYs + + A \l {The Property System}{Q_PROPERTY} that defines \c BINDABLE can be bound and + used in binding expressions. You can implement such properties using \l {QProperty}, + \l {QObjectBindableProperty}, or \l {QObjectComputedProperty}. + + Q_PROPERTYs without \c BINDABLE can also be bound and be used in binding expressions, + as long as they define a \c NOTIFY signal. You must wrap the property in a \l QBindable + using the \c {QBindable(QObject* obj, const char* property)} constructor. Then, the + property can be bound using \l QBindable::setBinding() or used in a binding + expression via \l QBindable::value(). You must use \c QBindable::value() in binding + expressions instead of the normal property \c READ function (or \c MEMBER) to enable + dependency tracking if the property is not \c BINDABLE. + */ |