The QMetaDataWriterControl class provides write access to the meta-data of a QMediaService 's media. 更多...
头: | #include <QMetaDataWriterControl> |
qmake: | QT += multimedia |
继承: | QMediaControl |
该类已过时。 提供它是为使旧源代码能继续工作。强烈建议不要在新代码中使用它。
virtual | ~QMetaDataWriterControl () |
virtual QStringList | availableMetaData () const = 0 |
virtual bool | isMetaDataAvailable () const = 0 |
virtual bool | isWritable () const = 0 |
virtual QVariant | metaData (const QString & key ) const = 0 |
virtual void | setMetaData (const QString & key , const QVariant & value ) = 0 |
void | metaDataAvailableChanged (bool available ) |
void | metaDataChanged (const QString & key , const QVariant & value ) |
void | metaDataChanged () |
void | writableChanged (bool writable ) |
QMetaDataWriterControl (QObject * parent = nullptr) |
QMetaDataWriterControl_iid |
若 QMediaService can provide write access to the meta-data of its current media it will implement QMetaDataWriterControl. This control provides functions for both retrieving and setting meta-data values. Meta-data may be addressed by the keys defined in the QMediaMetaData 名称空间。
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 QMetaDataControl.
The interface name of QMetaDataWriterControl is
org.qt-project.qt.metadatawritercontrol/5.0
作为定义在
QMetaDataWriterControl_iid
.
另请参阅 QMediaService::requestControl () 和 QMediaObject .
[protected]
QMetaDataWriterControl::
QMetaDataWriterControl
(
QObject
*
parent
= nullptr)
Construct a QMetaDataWriterControl with parent . This class is meant as a base class for service specific meta data providers so this constructor is protected.
[signal]
void
QMetaDataWriterControl::
metaDataAvailableChanged
(
bool
available
)
Signal the availability of meta-data has changed, available will be true if the multimedia object has meta-data.
[signal]
void
QMetaDataWriterControl::
metaDataChanged
(const
QString
&
key
, const
QVariant
&
value
)
Signal the changes of one meta-data element value 采用给定 key .
注意: 信号 metaDataChanged 在此类中被重载。通过使用函数指针句法连接到此信号,Qt 提供用于获得如此范例展示的函数指针的方便帮助程序:
connect(metaDataWriterControl, QOverload<const QString &, const QVariant &>::of(&QMetaDataWriterControl::metaDataChanged), [=](const QString &key, const QVariant &value){ /* ... */ });
[signal]
void
QMetaDataWriterControl::
metaDataChanged
()
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.
注意: 信号 metaDataChanged 在此类中被重载。通过使用函数指针句法连接到此信号,Qt 提供用于获得如此范例展示的函数指针的方便帮助程序:
connect(metaDataWriterControl, QOverload<>::of(&QMetaDataWriterControl::metaDataChanged), [=](){ /* ... */ });
[signal]
void
QMetaDataWriterControl::
writableChanged
(
bool
writable
)
Signal a change in the writable status of meta-data, writable will be true if meta-data elements can be added or adjusted.
[虚拟]
QMetaDataWriterControl::
~QMetaDataWriterControl
()
Destroy the meta-data writer control.
[pure virtual]
QStringList
QMetaDataWriterControl::
availableMetaData
() const
返回元数据的可用键列表。
[pure virtual]
bool
QMetaDataWriterControl::
isMetaDataAvailable
() const
Identifies if meta-data is available from a media service.
Returns true if the meta-data is available and false otherwise.
[pure virtual]
bool
QMetaDataWriterControl::
isWritable
() const
Identifies if a media service's meta-data can be edited.
Returns true if the meta-data is writable and false otherwise.
[pure virtual]
QVariant
QMetaDataWriterControl::
metaData
(const
QString
&
key
) const
Returns the meta-data for the given key .
另请参阅 setMetaData ().
[pure virtual]
void
QMetaDataWriterControl::
setMetaData
(const
QString
&
key
, const
QVariant
&
value
)
设置 value of the meta-data element with the given key .
另请参阅 metaData ().
org.qt-project.qt.metadatawritercontrol/5.0
定义接口名为 QMetaDataWriterControl 类。