MediaSession.SessionCallback

SessionCallback

public SessionCallback ()

onCommandRequest

public int onCommandRequest (MediaSession session, 
                MediaSession.ControllerInfo controller, 
                SessionCommand command)

Called when a controller sent a command which will be sent directly to one of the following:

• SessionPlayer
• AudioManager

Return SessionResult.RESULT_SUCCESS to proceed the command. If something else is returned, command wouldn't be sent and the controller would receive the code with it.

Parameters
session	MediaSession: the session for this event
controller	MediaSession.ControllerInfo: controller information.
command	SessionCommand: a command. This method will be called for every single command.

Returns
int	RESULT_SUCCESS if you want to proceed with incoming command. Another code for ignore.

onConnect

public SessionCommandGroup onConnect (MediaSession session, 
                MediaSession.ControllerInfo controller)

Called when a controller is created for this session. Return allowed commands for controller. By default it allows all connection requests and commands.

You can reject the connection by return null. In that case, the controller receives MediaController.ControllerCallback.onDisconnected(MediaController) and cannot be used.

The controller hasn't connected yet in this method, so calls to the controller (e.g. MediaSession.sendCustomCommand(MediaSession.ControllerInfo, SessionCommand, Bundle), MediaSession.setCustomLayout(MediaSession.ControllerInfo, List)) would be ignored. Override onPostConnect(MediaSession, MediaSession.ControllerInfo) for the custom initialization for the controller instead.

Parameters
session	MediaSession: the session for this event
controller	MediaSession.ControllerInfo: controller information.

Returns
SessionCommandGroup	allowed commands. Can be null to reject connection.

onCreateMediaItem

public MediaItem onCreateMediaItem (MediaSession session, 
                MediaSession.ControllerInfo controller, 
                String mediaId)

Called when a controller has sent a command with a MediaItem to add a new media item to this session. Being specific, this will be called for following APIs.

1. MediaController.addPlaylistItem(int, String)
2. MediaController.replacePlaylistItem(int, String)
3. MediaController.setPlaylist(List, MediaMetadata)
4. MediaController.setMediaItem(String)

Override this to translate incoming mediaId to a MediaItem to be understood by your player. For example, a player may only understand FileMediaItem, UriMediaItem, and CallbackMediaItem. Check the documentation of the player that you're using.

If the given media ID is valid, you should return the media item with the given media ID. If the ID doesn't match, an RuntimeException will be thrown. You may return null if the given item is invalid. Here's the behavior when it happens.

Controller command	Behavior when null is returned
addPlaylistItem	Ignore
replacePlaylistItem	Ignore
setPlaylist	Ignore null items, and build a list with non-null items. Call SessionPlayer.setPlaylist(List, MediaMetadata) with the list
setMediaItem	Ignore

This will be called on the same thread where onCommandRequest(MediaSession, MediaSession.ControllerInfo, SessionCommand) and commands with the media controller will be executed.

Default implementation returns the null.

Parameters
session	MediaSession: the session for this event
controller	MediaSession.ControllerInfo: controller information
mediaId	String: non-empty media id for creating item with

Returns
MediaItem	translated media item for player with the mediaId. Can be null to ignore.

onCustomCommand

public SessionResult onCustomCommand (MediaSession session, 
                MediaSession.ControllerInfo controller, 
                SessionCommand customCommand, 
                Bundle args)

Called when a controller sent a custom command through MediaController.sendCustomCommand(SessionCommand, Bundle).

Interoperability: This would be also called by #sendCustomAction(String, Bundle, CustomActionCallback). If so, extra from sendCustomAction will be considered as args and customCommand would have null extra.

Parameters
session	MediaSession: the session for this event
controller	MediaSession.ControllerInfo: controller information
customCommand	SessionCommand: custom command.
args	Bundle: optional arguments

Returns
SessionResult	result of handling custom command. A runtime exception will be thrown if null is returned.

onDisconnected

public void onDisconnected (MediaSession session, 
                MediaSession.ControllerInfo controller)

Called when a controller is disconnected.

Interoperability: For legacy controller, this is called when the controller doesn't send any command for a while. It's because there were no explicit disconnect API in legacy controller API.

Parameters
session	MediaSession: the session for this event
controller	MediaSession.ControllerInfo: controller information

onFastForward

public int onFastForward (MediaSession session, 
                MediaSession.ControllerInfo controller)

Called when a controller called MediaController.fastForward().

It can be implemented in many ways. For example, it can be implemented by seeking forward once, series of seeking forward, or increasing playback speed.

Parameters
session	MediaSession: the session for this event
controller	MediaSession.ControllerInfo: controller information

Returns
int

onPostConnect

public void onPostConnect (MediaSession session, 
                MediaSession.ControllerInfo controller)

Called immediately after a controller is connected. This is a convenient method to add custom initialization between the session and a controller.

Note that calls to the controller (e.g. MediaSession.sendCustomCommand(MediaSession.ControllerInfo, SessionCommand, Bundle), MediaSession.setCustomLayout(MediaSession.ControllerInfo, List)) work here but don't work in onConnect(MediaSession, MediaSession.ControllerInfo) because the controller hasn't connected yet in onConnect(MediaSession, MediaSession.ControllerInfo).

Parameters
session	MediaSession: the session for this event
controller	MediaSession.ControllerInfo: controller information.

onRewind

public int onRewind (MediaSession session, 
                MediaSession.ControllerInfo controller)

Called when a controller called MediaController.rewind().

It can be implemented in many ways. For example, it can be implemented by seeking backward once, series of seeking backward, or decreasing playback speed.

Parameters
session	MediaSession: the session for this event
controller	MediaSession.ControllerInfo: controller information

Returns
int

onSetMediaUri

public int onSetMediaUri (MediaSession session, 
                MediaSession.ControllerInfo controller, 
                Uri uri, 
                Bundle extras)

Called when a controller requested to set the specific media item(s) represented by a URI through MediaController.setMediaUri(Uri, Bundle).

The implementation should create proper media item(s) for the given uri and call SessionPlayer.setMediaItem(MediaItem) or SessionPlayer.setPlaylist(List, MediaMetadata).

When MediaControllerCompat is connected and sends commands with following methods, the uri would have the following patterns:

Method	Uri pattern
prepareFromUri	The uri passed as argument
prepareFromMediaId	androidx://media2-session/prepareFromMediaId?id=[mediaId]
prepareFromSearch	androidx://media2-session/prepareFromSearch?query=[query]
playFromUri	The uri passed as argument
playFromMediaId	androidx://media2-session/playFromMediaId?id=[mediaId]
playFromSearch	androidx://media2-session/playFromSearch?query=[query]

SessionPlayer.prepare() or SessionPlayer.play() would be followed if this is called by above methods.

Parameters
session	MediaSession: the session for this event
controller	MediaSession.ControllerInfo: controller information
uri	Uri: uri
extras	Bundle: optional extra bundle

Returns
int

onSetRating

public int onSetRating (MediaSession session, 
                MediaSession.ControllerInfo controller, 
                String mediaId, 
                Rating rating)

Called when a controller set rating of a media item through MediaController.setRating(String, Rating).

To allow setting user rating for a MediaItem, the media item's metadata should have Rating with the key MediaMetadata.METADATA_KEY_USER_RATING, in order to provide possible rating style for controller. Controller will follow the rating style.

Parameters
session	MediaSession: the session for this event
controller	MediaSession.ControllerInfo: controller information
mediaId	String: non-empty media id
rating	Rating: new rating from the controller

Returns
int

onSkipBackward

public int onSkipBackward (MediaSession session, 
                MediaSession.ControllerInfo controller)

Called when a controller called MediaController.skipBackward().

It's recommended to seek backward within the current media item, but its detail may vary. For example, it can be implemented by seeking backward for the fixed amount of seconds, or seeking backward to the nearest bookmark.

Parameters
session	MediaSession: the session for this event
controller	MediaSession.ControllerInfo: controller information

Returns
int

onSkipForward

public int onSkipForward (MediaSession session, 
                MediaSession.ControllerInfo controller)

Called when a controller called MediaController.skipForward().

It's recommended to seek forward within the current media item, but its detail may vary. For example, it can be implemented by seeking forward for the fixed amount of seconds, or seeking forward to the nearest bookmark.

Parameters
session	MediaSession: the session for this event
controller	MediaSession.ControllerInfo: controller information

Returns
int