QMediaPlaylist Class | Qt Multimedia 5.9

Qt 5.9 | Qt Multimedia | C++ Classes | QMediaPlaylist

Qt 5.9.3 Reference Documentation

# QMediaPlaylist Class

The QMediaPlaylist class provides a list of media content to play. More...

Header: | #include <QMediaPlaylist>
qmake: | QT += multimedia
Inherits: | QObject and QMediaBindableInterface

- List of all members, including inherited members

## Public Types

enum | Error { NoError, FormatError, FormatNotSupportedError, NetworkError, AccessDeniedError }
enum | PlaybackMode { CurrentItemOnce, CurrentItemInLoop, Sequential, Loop, Random }

## Properties

- currentIndex : int
- currentMedia : const QMediaContent
- playbackMode : QMediaPlaylist::PlaybackMode

- 1 property inherited from QObject

## Public Functions

| QMediaPlaylist(QObject *parent = Q_NULLPTR)
virtual | ~QMediaPlaylist()
bool | addMedia(const QMediaContent &content)
bool | addMedia(const QList<QMediaContent> &items)
bool | clear()
int | currentIndex() const
QMediaContent | currentMedia() const
Error | error() const
QString | errorString() const
bool | insertMedia(int pos, const QMediaContent &content)
bool | insertMedia(int pos, const QList<QMediaContent> &items)
bool | isEmpty() const
bool | isReadOnly() const
void | load(const QNetworkRequest &request, const char *format = Q_NULLPTR)
void | load(const QUrl &location, const char *format = Q_NULLPTR)
void | load(QIODevice *device, const char *format = Q_NULLPTR)
QMediaContent | media(int index) const
int | mediaCount() const
bool | moveMedia(int from, int to)
int | nextIndex(int steps = 1) const
PlaybackMode | playbackMode() const
int | previousIndex(int steps = 1) const
bool | removeMedia(int pos)
bool | removeMedia(int start, int end)
bool | save(const QUrl &location, const char *format = Q_NULLPTR)
bool | save(QIODevice *device, const char *format)
void | setPlaybackMode(PlaybackMode mode)

## Reimplemented Public Functions

virtual QMediaObject * | mediaObject() const override

- 32 public functions inherited from QObject
- 1 public function inherited from QMediaBindableInterface

## Public Slots

void | next()
void | previous()
void | setCurrentIndex(int playlistPosition)
void | shuffle()

- 1 public slot inherited from QObject

## Signals

void | currentIndexChanged(int position)
void | currentMediaChanged(const QMediaContent &content)
void | loadFailed()
void | loaded()
void | mediaAboutToBeInserted(int start, int end)
void | mediaAboutToBeRemoved(int start, int end)
void | mediaChanged(int start, int end)
void | mediaInserted(int start, int end)
void | mediaRemoved(int start, int end)
void | playbackModeChanged(QMediaPlaylist::PlaybackMode mode)

- 2 signals inherited from QObject

### Additional Inherited Members

- 1 public variable inherited from QObject
- 10 static public members inherited from QObject
- 9 protected functions inherited from QObject
- 1 protected function inherited from QMediaBindableInterface
- 2 protected variables inherited from QObject

## Detailed Description

The QMediaPlaylist class provides a list of media content to play.

QMediaPlaylist is intended to be used with other media objects, like QMediaPlayer.

QMediaPlaylist allows to access the service intrinsic playlist functionality if available, otherwise it provides the local memory playlist implementation.

      playlist = new QMediaPlaylist;
      playlist->addMedia(QUrl("http://example.com/movie1.mp4"));
      playlist->addMedia(QUrl("http://example.com/movie2.mp4"));
      playlist->addMedia(QUrl("http://example.com/movie3.mp4"));
      playlist->setCurrentIndex(1);

      player = new QMediaPlayer;
      player->setPlaylist(playlist);

      videoWidget = new QVideoWidget;
      player->setVideoOutput(videoWidget);
      videoWidget->show();

      player->play();

Depending on playlist source implementation, most of the playlist mutating operations can be asynchronous.

See also QMediaContent.

## Member Type Documentation

### enum QMediaPlaylist::Error

This enum describes the QMediaPlaylist error codes.

Constant | Value | Description
--- | --- | ---
`QMediaPlaylist::NoError` | `0` | No errors.
`QMediaPlaylist::FormatError` | `1` | Format error.
`QMediaPlaylist::FormatNotSupportedError` | `2` | Format not supported.
`QMediaPlaylist::NetworkError` | `3` | Network error.
`QMediaPlaylist::AccessDeniedError` | `4` | Access denied error.

### enum QMediaPlaylist::PlaybackMode

The QMediaPlaylist::PlaybackMode describes the order items in playlist are played.

Constant | Value | Description
--- | --- | ---
`QMediaPlaylist::CurrentItemOnce` | `0` | The current item is played only once.
`QMediaPlaylist::CurrentItemInLoop` | `1` | The current item is played repeatedly in a loop.
`QMediaPlaylist::Sequential` | `2` | Playback starts from the current and moves through each successive item until the last is reached and then stops. The next item is a null item when the last one is currently playing.
`QMediaPlaylist::Loop` | `3` | Playback restarts at the first item after the last has finished playing.
`QMediaPlaylist::Random` | `4` | Play items in random order.

## Property Documentation

### currentIndex : int

Current position.

Access functions:

int | currentIndex() const
void | setCurrentIndex(int playlistPosition)

Notifier signal:

void | currentIndexChanged(int position)

### currentMedia : const QMediaContent

Current media content.

Access functions:

QMediaContent | currentMedia() const

Notifier signal:

void | currentMediaChanged(const QMediaContent &content)

### playbackMode : QMediaPlaylist::PlaybackMode

This property defines the order that items in the playlist are played.

Access functions:

PlaybackMode | playbackMode() const
void | setPlaybackMode(PlaybackMode mode)

Notifier signal:

void | playbackModeChanged(QMediaPlaylist::PlaybackMode mode)

See also QMediaPlaylist::PlaybackMode.

## Member Function Documentation

### QMediaPlaylist::QMediaPlaylist(QObject *parent = Q_NULLPTR)

Create a new playlist object with the given parent.

### `[virtual]` QMediaPlaylist::~QMediaPlaylist()

Destroys the playlist.

### bool QMediaPlaylist::addMedia(const QMediaContent &content)

Append the media content to the playlist.

Returns true if the operation is successful, otherwise returns false.

### bool QMediaPlaylist::addMedia(const QList<QMediaContent> &items)

Append multiple media content items to the playlist.

Returns true if the operation is successful, otherwise returns false.

### bool QMediaPlaylist::clear()

Remove all the items from the playlist.

Returns true if the operation is successful, otherwise return false.

### int QMediaPlaylist::currentIndex() const

Returns position of the current media content in the playlist.

Note: Getter function for property currentIndex.

See also setCurrentIndex().

### `[signal]` void QMediaPlaylist::currentIndexChanged(int position)

Signal emitted when playlist position changed to position.

Note: Notifier signal for property currentIndex.

### QMediaContent QMediaPlaylist::currentMedia() const

Returns the current media content.

Note: Getter function for property currentMedia.

### `[signal]` void QMediaPlaylist::currentMediaChanged(const QMediaContent &content)

Signal emitted when current media changes to content.

Note: Notifier signal for property currentMedia.

### Error QMediaPlaylist::error() const

Returns the last error condition.

### QString QMediaPlaylist::errorString() const

Returns the string describing the last error condition.

### bool QMediaPlaylist::insertMedia(int pos, const QMediaContent &content)

Insert the media content to the playlist at position pos.

Returns true if the operation is successful, otherwise returns false.

### bool QMediaPlaylist::insertMedia(int pos, const QList<QMediaContent> &items)

Insert multiple media content items to the playlist at position pos.

Returns true if the operation is successful, otherwise returns false.

### bool QMediaPlaylist::isEmpty() const

Returns true if the playlist contains no items, otherwise returns false.

See also mediaCount().

### bool QMediaPlaylist::isReadOnly() const

Returns true if the playlist can be modified, otherwise returns false.

See also mediaCount().

### void QMediaPlaylist::load(const QNetworkRequest &request, const char *format = Q_NULLPTR)

Load playlist using network request. If format is specified, it is used, otherwise format is guessed from playlist name and data.

New items are appended to playlist.

QMediaPlaylist::loaded() signal is emitted if playlist was loaded successfully, otherwise the playlist emits loadFailed().

### void QMediaPlaylist::load(const QUrl &location, const char *format = Q_NULLPTR)

Load playlist from location. If format is specified, it is used, otherwise format is guessed from location name and data.

New items are appended to playlist.

QMediaPlaylist::loaded() signal is emitted if playlist was loaded successfully, otherwise the playlist emits loadFailed().

### void QMediaPlaylist::load(QIODevice *device, const char *format = Q_NULLPTR)

Load playlist from QIODevice device. If format is specified, it is used, otherwise format is guessed from device data.

New items are appended to playlist.

QMediaPlaylist::loaded() signal is emitted if playlist was loaded successfully, otherwise the playlist emits loadFailed().

### `[signal]` void QMediaPlaylist::loadFailed()

Signal emitted if failed to load playlist.

### `[signal]` void QMediaPlaylist::loaded()

Signal emitted when playlist finished loading.

### QMediaContent QMediaPlaylist::media(int index) const

Returns the media content at index in the playlist.

### `[signal]` void QMediaPlaylist::mediaAboutToBeInserted(int start, int end)

Signal emitted when items are to be inserted at start and ending at end.

### `[signal]` void QMediaPlaylist::mediaAboutToBeRemoved(int start, int end)

Signal emitted when item are to be deleted at start and ending at end.

### `[signal]` void QMediaPlaylist::mediaChanged(int start, int end)

This signal is emitted after media has been changed in the playlist between start and end positions inclusive.

### int QMediaPlaylist::mediaCount() const

Returns the number of items in the playlist.

See also isEmpty().

### `[signal]` void QMediaPlaylist::mediaInserted(int start, int end)

This signal is emitted after media has been inserted into the playlist. The new items are those between start and end inclusive.

### `[override virtual]` QMediaObject *QMediaPlaylist::mediaObject() const

Reimplemented from QMediaBindableInterface::mediaObject().

Returns the QMediaObject instance that this QMediaPlaylist is bound too, or 0 otherwise.

### `[signal]` void QMediaPlaylist::mediaRemoved(int start, int end)

This signal is emitted after media has been removed from the playlist. The removed items are those between start and end inclusive.

### bool QMediaPlaylist::moveMedia(int from, int to)

Move the item from position from to position to.

Returns true if the operation is successful, otherwise false.

This function was introduced in Qt 5.7.

### `[slot]` void QMediaPlaylist::next()

Advance to the next media content in playlist.

### int QMediaPlaylist::nextIndex(int steps = 1) const

Returns the index of the item, which would be current after calling next() steps times.

Returned value depends on the size of playlist, current position and playback mode.

See also QMediaPlaylist::playbackMode() and previousIndex().

### `[signal]` void QMediaPlaylist::playbackModeChanged(QMediaPlaylist::PlaybackMode mode)

Signal emitted when playback mode changed to mode.

Note: Notifier signal for property playbackMode.

### `[slot]` void QMediaPlaylist::previous()

Return to the previous media content in playlist.

### int QMediaPlaylist::previousIndex(int steps = 1) const

Returns the index of the item, which would be current after calling previous() steps times.

See also QMediaPlaylist::playbackMode() and nextIndex().

### bool QMediaPlaylist::removeMedia(int pos)

Remove the item from the playlist at position pos.

Returns true if the operation is successful, otherwise return false.

### bool QMediaPlaylist::removeMedia(int start, int end)

Remove items in the playlist from start to end inclusive.

Returns true if the operation is successful, otherwise return false.

### bool QMediaPlaylist::save(const QUrl &location, const char *format = Q_NULLPTR)

Save playlist to location. If format is specified, it is used, otherwise format is guessed from location name.

Returns true if playlist was saved successfully, otherwise returns false.

### bool QMediaPlaylist::save(QIODevice *device, const char *format)

Save playlist to QIODevice device using format format.

Returns true if playlist was saved successfully, otherwise returns false.

### `[slot]` void QMediaPlaylist::setCurrentIndex(int playlistPosition)

Activate media content from playlist at position playlistPosition.

Note: Setter function for property currentIndex.

See also currentIndex().

### `[slot]` void QMediaPlaylist::shuffle()

Shuffle items in the playlist.