Qt 之QMediaPlayer类详解

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这是一个播放多媒体流的类

几个重要的枚举类型

enum QMediaPlayer::MediaStatus

Defines the status of a media player"s current media.

Constant	Value	Description
QMediaPlayer::UnknownMediaStatus	0	The status of the media cannot be determined.
QMediaPlayer::NoMedia	1	The is no current media. The player is in the StoppedState.
QMediaPlayer::LoadingMedia	2	The current media is being loaded. The player may be in any state.
QMediaPlayer::LoadedMedia	3	The current media has been loaded. The player is in the StoppedState.
QMediaPlayer::StalledMedia	4	Playback of the current media has stalled due to insufficient buffering or some other temporary interruption. The player is in thePlayingState or PausedState.
QMediaPlayer::BufferingMedia	5	The player is buffering data but has enough data buffered for playback to continue for the immediate future. The player is in thePlayingState or PausedState.
QMediaPlayer::BufferedMedia	6	The player has fully buffered the current media. The player is in thePlayingState or PausedState.
QMediaPlayer::EndOfMedia	7	Playback has reached the end of the current media. The player is in theStoppedState.
QMediaPlayer::InvalidMedia	8	The current media cannot be played. The player is in the StoppedState.

Properties：

• audioAvailable : const bool     音频是否有效   notifier信号 void audioAvailableChanged(bool available)
  
• bufferStatus : const int     This property holds the percentage of the temporary buffer filled before playback begins or resumes, from (empty) to (full)
  
• currentMedia : const QMediaContent  当前正在播放的媒体的内容
  
• duration : const qint64    当前媒体的duration  notifier信号   void durationChanged(qint64 duration)
  
• error : const QString    a string describing the last error condition
  
• media : QMediaContent   a string describing the last error condition
  
• mediaStatus : const MediaStatus 当前媒体流的状态   notifier信号 void mediaStatusChanged(QMediaPlayer::MediaStatus status)
  
• muted : bool    是否静音 isMuted();setMuted()  notifier信号  void mutedChanged(bool muted)
  

• playbackRate : qreal  播放速率；1是正常速率，大于1加快播放  void setPlaybackRate(qreal rate)；notifier信号 void playbackRateChanged(qreal rate)
  
• position : qint64  决定当前视频的播放位置（ms） void setPosition(qint64 position) notifier信号 void positionChanged(qint64 position)
  
• seekable : const bool may change across the life time of the QMediaPlayer object, use the seekableChanged() signal to monitor changes.
  
• state : const State 播放器的播放状态  notifer signal void stateChanged(QMediaPlayer::State state)
  
• videoAvailable : const bool
  
• volume : int  The playback volume is linear in effect and the value can range from 0 - 100  notifer signal void volumeChanged(int volume)
  

公有成员函数

	QMediaPlayer(QObject * parent = 0, Flags flags = 0)
	~QMediaPlayer()
int	bufferStatus() const
QMediaContent	currentMedia() const
QNetworkConfiguration	currentNetworkConfiguration() const
qint64	duration() const
Error	error() const
QString	errorString() const
bool	isAudioAvailable() const
bool	isMuted() const
bool	isSeekable() const
bool	isVideoAvailable() const
QMediaContent	media() const
MediaStatus	mediaStatus() const
const QIODevice *	mediaStream() const
qreal	playbackRate() const
QMediaPlaylist *	playlist() const
qint64	position() const
void	setVideoOutput(QVideoWidget * output) Attach a QVideoWidget video output to the media player ，可替换新
void	setVideoOutput(QGraphicsVideoItem * output)
void	setVideoOutput(QAbstractVideoSurface * surface) Sets a video surface as the video output of a media player
State	state() const
int	volume() const

公有槽

void	pause()
void	play() 开始或重新开始播放当前媒体流
void	setMedia(const QMediaContent & media, QIODevice * stream = 0)
void	setMuted(bool muted)
void	setNetworkConfigurations(const QList & configurations)
void	setPlaybackRate(qreal rate)
void	setPlaylist(QMediaPlaylist * playlist)
void	setPosition(qint64 position)
void	setVolume(int volume)
void	stop() Stop playing, and reset the play position to the beginning.

信号：

void	audioAvailableChanged(bool available)
void	bufferStatusChanged(int percentFilled)
void	currentMediaChanged(const QMediaContent & media)
void	durationChanged(qint64 duration)
void	error(QMediaPlayer::Error error)
void	mediaChanged(const QMediaContent & media)
void	mediaStatusChanged(QMediaPlayer::MediaStatus status)
void	mutedChanged(bool muted)
void	networkConfigurationChanged(const QNetworkConfiguration & configuration)
void	playbackRateChanged(qreal rate)
void	positionChanged(qint64 position)
void	seekableChanged(bool seekable)
void	stateChanged(QMediaPlayer::State state)
void	videoAvailableChanged(bool videoAvailable)
void	volumeChanged(int volume)

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