QQmlListProperty class allows applications to expose list-like properties of QObject -derived classes to QML. 更多...
| 头： | #include <QQmlListProperty> |
| qmake: | QT += qml |
| Since: | Qt 5.0 |
| typedef | AppendFunction |
| typedef | AtFunction |
| typedef | ClearFunction |
| typedef | CountFunction |
| QQmlListProperty (QObject * object , QList<T *> & list ) | |
| QQmlListProperty (QObject * object , void * data , AppendFunction append , CountFunction count , AtFunction at , ClearFunction clear ) | |
| QQmlListProperty (QObject * object , void * data , CountFunction count , AtFunction at ) | |
| bool | operator== (const QQmlListProperty & other ) const |
QQmlListProperty class allows applications to expose list-like properties of QObject -derived classes to QML.
QML has many list properties, where more than one object value can be assigned. The use of a list property from QML looks like this:
FruitBasket {
fruit: [
Apple {},
Orange{},
Banana{}
]
}
QQmlListProperty encapsulates a group of function pointers that represent the set of actions QML can perform on the list - adding items, retrieving items and clearing the list. In the future, additional operations may be supported. All list properties must implement the append operation, but the rest are optional.
To provide a list property, a C++ class must implement the operation callbacks, and then return an appropriate QQmlListProperty value from the property getter. List properties should have no setter. In the example above, the Q_PROPERTY () declarative will look like this:
Q_PROPERTY(QQmlListProperty<Fruit> fruit READ fruit);
QML list properties are type-safe - in this case
Fruit
是
QObject
type that
Apple
,
Orange
and
Banana
all derive from.
Qt Quick 1 version of this class is named QDeclarativeListProperty.
另请参阅 扩展 QML - 对象和列表特性类型范例 .
同义词
void (*)(QQmlListProperty<T> *property, T *value)
.
Append the value to the list property .
同义词
T *(*)(QQmlListProperty<T> *property, int index)
.
Return the element at position index in the list property .
同义词
void (*)(QQmlListProperty<T> *property)
.
Clear the list property .
同义词
int (*)(QQmlListProperty<T> *property)
.
Return the number of elements in the list property .
Convenience constructor for making a QQmlListProperty value from an existing QList list 。 list reference must remain valid for as long as object exists. object must be provided.
Generally this constructor should not be used in production code, as a writable QList violates QML's memory management rules. However, this constructor can be very useful while prototyping.
构造 QQmlListProperty from a set of operation functions append , count , at ，和 clear . An opaque data handle may be passed which can be accessed from within the operation functions. The list property remains valid while object exists.
Null pointers can be passed for any function. If any null pointers are passed in, the list will be neither designable nor alterable by the debugger. It is recommended to provide valid pointers for all functions.
Construct a readonly QQmlListProperty from a set of operation functions count and at . An opaque data handle may be passed which can be accessed from within the operation functions. The list property remains valid while object exists.
返回 true，若此 QQmlListProperty 等于 other ，否则 false。