內容

• 公共函數
• 信號
• 保護函數
• 宏
• 詳細描述

QMetaDataReaderControl Class

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

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

• 所有成員列錶，包括繼承成員

公共函數

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

• 32 公共函數繼承自 QObject

信號

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

• 2 信號繼承自 QObject

保護函數

QMetaDataReaderControl (QObject * parent = Q_NULLPTR)

• 9 保護函數繼承自 QObject

宏

QMetaDataReaderControl_iid

額外繼承成員

• 1 特性繼承自 QObject
• 1 公共槽繼承自 QObject
• 11 靜態公共成員繼承自 QObject

詳細描述

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

若 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 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 QMetaDataReaderControl .

接口名稱對於 QMetaDataReaderControl is org.qt-project.qt.metadatareadercontrol/5.0 作為定義在 QMetaDataReaderControl_iid .

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

成員函數文檔編製

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

構造 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.

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

返迴元數據的可用鍵列錶。

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

Returns the meta-data for the given key .

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

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

[signal] void QMetaDataReaderControl:: 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 在此類中是重載。要使用函數指針句法連接到此信號，必須在靜態鑄造中指定信號類型，如此範例所示：

connect(metaDataReaderControl, static_cast<void(QMetaDataReaderControl::*)()>(&QMetaDataReaderControl::metaDataChanged),
    [=](){ /* ... */ });
					

[signal] void QMetaDataReaderControl:: 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 在此類中是重載。要使用函數指針句法連接到此信號，必須在靜態鑄造中指定信號類型，如此範例所示：

connect(metaDataReaderControl, static_cast<void(QMetaDataReaderControl::*)(const QString &, const QVariant &)>(&QMetaDataReaderControl::metaDataChanged),
    [=](const QString &key, const QVariant &value){ /* ... */ });
					

宏文檔編製

QMetaDataReaderControl_iid

org.qt-project.qt.metadatareadercontrol/5.0

定義接口名為 QMetaDataReaderControl 類。