内容

• 公共函数
• 信号
• 保护函数
• 宏
• 详细描述

QMetaDataWriterControl Class

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。

• 所有成员列表，包括继承成员

公共函数

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

信号

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

保护函数

QMetaDataWriterControl (QObject * parent = nullptr)

宏

QMetaDataWriterControl_iid

详细描述

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 .

成员函数文档编制

[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.

[virtual] 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 ().

宏文档编制

QMetaDataWriterControl_iid

org.qt-project.qt.metadatawritercontrol/5.0

定义接口名为 QMetaDataWriterControl 类。