QMetaDataReaderControl Class

The QMetaDataReaderControl class provides read access to the meta-data of a QMediaService's media. More...

Header: #include <QMetaDataReaderControl>
qmake: QT += multimedia
Inherits: QMediaControl.

Public Functions

~QMetaDataReaderControl()
virtual QStringList availableMetaData() const = 0
virtual bool isMetaDataAvailable() const = 0
virtual QVariant metaData(const QString & key) const = 0

Signals

void metaDataAvailableChanged(bool available)
void metaDataChanged()
void metaDataChanged(const QString & key, const QVariant & value)

Protected Functions

QMetaDataReaderControl(QObject * parent = 0)

Macros

QMetaDataReaderControl_iid

Detailed Description

The QMetaDataReaderControl class provides read access to the meta-data of a QMediaService's media.

If a QMediaService can provide read or write access to the meta-data of its current media it will implement QMetaDataReaderControl. This control provides functions for both retrieving and setting meta-data values. Meta-data may be addressed by the keys defined in the QMediaMetaData namespace.

The functionality provided by this control is exposed to application code by the meta-data members of QMediaObject, and so meta-data access is potentially available in any of the media object classes. Any media service may implement QMetaDataReaderControl.

The interface name of QMetaDataReaderControl is org.qt-project.qt.metadatareadercontrol/5.0 as defined in QMetaDataReaderControl_iid.

See also QMediaService::requestControl() and QMediaObject.

Member Function Documentation

QMetaDataReaderControl::QMetaDataReaderControl(QObject * parent = 0) [protected]

Construct a QMetaDataReaderControl with parent. This class is meant as a base class for service specific meta data providers so this constructor is protected.

QMetaDataReaderControl::~QMetaDataReaderControl()

Destroy the meta-data object.

QStringList QMetaDataReaderControl::availableMetaData() const [pure virtual]

Returns a list of keys there is meta-data available for.

bool QMetaDataReaderControl::isMetaDataAvailable() const [pure virtual]

Identifies if meta-data is available from a media service.

Returns true if the meta-data is available and false otherwise.

QVariant QMetaDataReaderControl::metaData(const QString & key) const [pure virtual]

Returns the meta-data for the given key.

void QMetaDataReaderControl::metaDataAvailableChanged(bool available) [signal]

Signal the availability of meta-data has changed, available will be true if the multimedia object has meta-data.

void QMetaDataReaderControl::metaDataChanged() [signal]

Signal the changes of meta-data.

If multiple meta-data elements are changed, metaDataChanged(const QString &key, const QVariant &value) signal is emitted for each of them with metaDataChanged() changed emitted once.

void QMetaDataReaderControl::metaDataChanged(const QString & key, const QVariant & value) [signal]

Signal the changes of one meta-data element value with the given key.

Macro Documentation

QMetaDataReaderControl_iid

org.qt-project.qt.metadatareadercontrol/5.0

Defines the interface name of the QMetaDataReaderControl class.