The QDeclarativePropertyMap class allows you to set key-value pairs that can be used in QML bindings. More...
#include <QDeclarativePropertyMap>Inherits QObject.
This class was introduced in Qt 4.7.
| QDeclarativePropertyMap ( QObject * parent = 0 ) | |
| virtual | ~QDeclarativePropertyMap () |
| void | clear ( const QString & key ) |
| bool | contains ( const QString & key ) const |
| int | count () const |
| void | insert ( const QString & key, const QVariant & value ) |
| bool | isEmpty () const |
| int | size () const |
| QVariant | value ( const QString & key ) const |
| QVariant & | operator[] ( const QString & key ) |
| QVariant | operator[] ( const QString & key ) const |
| void | valueChanged ( const QString & key, const QVariant & value ) |
The QDeclarativePropertyMap class allows you to set key-value pairs that can be used in QML bindings.
QDeclarativePropertyMap provides a convenient way to expose domain data to the UI layer. The following example shows how you might declare data in C++ and then access it in QML.
In the C++ file:
// create our data QDeclarativePropertyMap ownerData; ownerData.insert("name", QVariant(QString("John Smith"))); ownerData.insert("phone", QVariant(QString("555-5555"))); // expose it to the UI layer QDeclarativeView view; QDeclarativeContext *ctxt = view.rootContext(); ctxt->setContextProperty("owner", &ownerData); view.setSource(QUrl::fromLocalFile("main.qml")); view.show();
Then, in main.qml:
Text { text: owner.name + " " + owner.phone }
The binding is dynamic - whenever a key's value is updated, anything bound to that key will be updated as well.
To detect value changes made in the UI layer you can connect to the valueChanged() signal. However, note that valueChanged() is NOT emitted when changes are made by calling insert() or clear() - it is only emitted when a value is updated from QML.
Note: It is not possible to remove keys from the map; once a key has been added, you can only modify or clear its associated value.
Constructs a bindable map with parent object parent.
Destroys the bindable map.
Clears the value (if any) associated with key.
Returns true if the map contains key.
See also size().
This is an overloaded function.
Same as size().
Sets the value associated with key to value.
If the key doesn't exist, it is automatically created.
Returns true if the map contains no keys; otherwise returns false.
See also size().
Returns the number of keys in the map.
See also isEmpty() and count().
Returns the value associated with key.
If no value has been set for this key (or if the value has been cleared), an invalid QVariant is returned.
This signal is emitted whenever one of the values in the map is changed. key is the key corresponding to the value that was changed.
Note: valueChanged() is NOT emitted when changes are made by calling insert() or clear() - it is only emitted when a value is updated from QML.
Returns the value associated with the key key as a modifiable reference.
If the map contains no item with key key, the function inserts an invalid QVariant into the map with key key, and returns a reference to it.
See also insert() and value().
This is an overloaded function.
Same as value().