QMetaDataWriterControl Class

The QMetaDataWriterControl class provides write access to the meta-data of a QMediaService 's media. 更多...

頭：	#include <QMetaDataWriterControl>
qmake:	QT += multimedia
繼承：	QMediaControl

該類已過時。 提供它是為使舊源代碼能繼續工作。強烈建議不要在新代碼中使用它。

• 所有成員列錶，包括繼承成員

公共函數

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

信號

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

保護函數

QMetaDataWriterControl (QObject * parent = nullptr)

宏

QMetaDataWriterControl_iid

詳細描述

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 名稱空間。

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 作為定義在 QMetaDataWriterControl_iid .

另請參閱 QMediaService::requestControl () 和 QMediaObject .

成員函數文檔編製

[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 采用給定 key .

注意： 信號 metaDataChanged 在此類中被重載。通過使用函數指針句法連接到此信號，Qt 提供用於獲得如此範例展示的函數指針的方便幫助程序：

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： 信號 metaDataChanged 在此類中被重載。通過使用函數指針句法連接到此信號，Qt 提供用於獲得如此範例展示的函數指針的方便幫助程序：

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.

[虛擬] QMetaDataWriterControl:: ~QMetaDataWriterControl ()

Destroy the meta-data writer control.

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

返迴元數據的可用鍵列錶。

[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 .

另請參閱 setMetaData ().

[pure virtual] void QMetaDataWriterControl:: setMetaData (const QString & key , const QVariant & value )

設置 value of the meta-data element with the given key .

另請參閱 metaData ().

宏文檔編製

QMetaDataWriterControl_iid

org.qt-project.qt.metadatawritercontrol/5.0

定義接口名為 QMetaDataWriterControl 類。

內容

1. 公共函數

2. 信號

3. 保護函數

4. 宏

5. 詳細描述