QBindable is a wrapper class around binding-enabled properties. It allows type-safe operations while abstracting the differences between the various property classes away. More...
Header: | #include <QBindable> |
CMake: | find_package(Qt6 COMPONENTS Core REQUIRED) target_link_libraries(mytarget PRIVATE Qt6::Core) |
qmake: | QT += core |
Inherits: | QUntypedBindable |
QPropertyBinding<T> | binding() const |
QPropertyBinding<T> | makeBinding(const QPropertyBindingSourceLocation &location = QT_PROPERTY_DEFAULT_BINDING_LOCATION) const |
QPropertyBinding<T> | setBinding(const QPropertyBinding<T> &binding) |
QPropertyBinding<T> | setBinding(Functor f) |
void | setValue(const T &value) |
QPropertyBinding<T> | takeBinding() |
T | value() const |
QBindable<T> helps to integrate Qt's traditional Q_PROPERTY with binding-enabled properties. If a property is backed by a QProperty, QObjectBindableProperty or QObjectComputedProperty, you can add BINDABLE
bindablePropertyName to the Q_PROPERTY declaration, where bindablePropertyName is a function returning an instance of QBindable constructed from the QProperty. The returned QBindable allows users of the property to set and query bindings of the property, without having to know the exact kind of binding-enabled property used.
class MyClass : public QObject { Q_OBJECT Q_PROPERTY(int x READ x WRITE setX NOTIFY xChanged BINDABLE bindableX) public: int x() const { return xProp; } void setX(int x) { xProp = x; } QBindable<int> bindableX() { return QBindable<int>(&xProp); } signals: void xChanged(); private: // Declare the instance of the bindable property data. Q_OBJECT_BINDABLE_PROPERTY(MyClass, int, xProp, &MyClass::xChanged) }; MyClass *myObject; QBindable<int> bindableX = myObject->bindableX(); qDebug() << bindableX.hasBinding(); // prints false QProperty<int> y {42}; bindableX.setBinding([&](){ return 2*y.value(); }); qDebug() << bindableX.hasBinding() << myObject->x(); // prints true 84
See also QMetaProperty::isBindable, QProperty, QObjectBindableProperty, QObjectComputedProperty, and Qt Bindable Properties.
Returns the currently set binding of the underlying property. If the property does not have a binding, the returned QPropertyBinding<T>
will be invalid.
See also setBinding and hasBinding.
Constructs a binding evaluating to the underlying property's value, using a specified source location.
Sets the underlying property's binding to binding. Does nothing if the QBindable is read-only or invalid.
See also binding, isReadOnly(), and isValid().
This is an overloaded function.
Creates a QPropertyBinding<T>
from f, and sets it as the underlying property's binding.
Sets the underlying property's value to value. This removes any currenltly set binding from it. This function has no effect if the QBindable is read-only or invalid.
See also value(), isValid(), isReadOnly(), and setBinding().
Removes the currently set binding of the underlying property and returns it. If the property does not have a binding, the returned QPropertyBinding<T>
will be invalid.
See also binding, setBinding, and hasBinding.
Returns the underlying property's current value. If the QBindable is invalid, a default constructed T
is returned.
See also setValue() and isValid().
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Licensed under the GNU Free Documentation License, Version 1.3.
https://doc.qt.io/qt-6.2/qbindable.html