diff options
Diffstat (limited to 'src/corelib/doc/src/objectmodel/properties.qdoc')
| -rw-r--r-- | src/corelib/doc/src/objectmodel/properties.qdoc | 26 |
1 files changed, 21 insertions, 5 deletions
diff --git a/src/corelib/doc/src/objectmodel/properties.qdoc b/src/corelib/doc/src/objectmodel/properties.qdoc index 66325ca6c0..37f54621a1 100644 --- a/src/corelib/doc/src/objectmodel/properties.qdoc +++ b/src/corelib/doc/src/objectmodel/properties.qdoc @@ -53,16 +53,22 @@ \snippet code/doc_src_properties.cpp 1 + Here is an example showing how to export member variables as Qt + properties using the \c MEMBER keyword. + Note that a \c NOTIFY signal must be specified to allow QML property bindings. + + \snippet code/doc_src_properties.cpp 8 + A property behaves like a class data member, but it has additional features accessible through the \l {Meta-Object System}. \list - \li A \c READ accessor function is required. It is for reading the - property value. Ideally, a const function is used for this purpose, - and it must return either the property's type or a pointer or - reference to that type. e.g., QWidget::focus is a read-only property - with \c READ function, QWidget::hasFocus(). + \li A \c READ accessor function is required if no \c MEMBER variable was + specified. It is for reading the property value. Ideally, a const function + is used for this purpose, and it must return either the property's type or a + pointer or reference to that type. e.g., QWidget::focus is a read-only + property with \c READ function, QWidget::hasFocus(). \li A \c WRITE accessor function is optional. It is for setting the property value. It must return void and must take exactly one @@ -71,6 +77,13 @@ QWidget::setEnabled(). Read-only properties do not need \c WRITE functions. e.g., QWidget::focus has no \c WRITE function. + \li A \c MEMBER variable association is required if no \c READ accessor + function is specified. This makes the given member variable + readable and writable without the need of creating \c READ and \c WRITE accessor + functions. It's still possible to use \c READ or \c WRITE accessor functions in + addition to \c MEMBER variable association (but not both), if you need to + control the variable access. + \li A \c RESET function is optional. It is for setting the property back to its context specific default value. e.g., QWidget::cursor has the typical \c READ and \c WRITE functions, QWidget::cursor() @@ -82,6 +95,9 @@ \li A \c NOTIFY signal is optional. If defined, it should specify one existing signal in that class that is emitted whenever the value of the property changes. + \c NOTIFY signals for \c MEMBER variables must take zero or one parameter, + which must be of the same type as the property. The parameter will take the + new value of the property. \li A \c REVISION number is optional. If included, it defines the property and its notifier signal to be used in a particular |