* A MediaSession should be created when an app wants to publish media playback * information or handle media keys. In general an app only needs one session * for all playback, though multiple sessions can be created to provide finer * grain controls of media. *
* Once a session is created the owner of the session may pass its * {@link #getSessionToken() session token} to other processes to allow them to * create a {@link MediaController} to interact with the session. *
* To receive commands, media keys, and other events a {@link Callback} must be * set with {@link #setCallback(Callback)} and {@link #setActive(boolean) * setActive(true)} must be called. *
* When an app is finished performing playback it must call {@link #release()} * to clean up the session and notify any controllers. *
* MediaSession objects are thread safe. */ public final class MediaSession { private static final String TAG = "MediaSession"; /** * Set this flag on the session to indicate that it can handle media button * events. */ public static final int FLAG_HANDLES_MEDIA_BUTTONS = 1 << 0; /** * Set this flag on the session to indicate that it handles transport * control commands through its {@link Callback}. */ public static final int FLAG_HANDLES_TRANSPORT_CONTROLS = 1 << 1; /** * System only flag for a session that needs to have priority over all other * sessions. This flag ensures this session will receive media button events * regardless of the current ordering in the system. * * @hide */ public static final int FLAG_EXCLUSIVE_GLOBAL_PRIORITY = 1 << 16; /** @hide */ @Retention(RetentionPolicy.SOURCE) @IntDef(flag = true, value = { FLAG_HANDLES_MEDIA_BUTTONS, FLAG_HANDLES_TRANSPORT_CONTROLS, FLAG_EXCLUSIVE_GLOBAL_PRIORITY }) public @interface SessionFlags { } private final Object mLock = new Object(); private final int mMaxBitmapSize; private final MediaSession.Token mSessionToken; private final MediaController mController; private final ISession mBinder; private final CallbackStub mCbStub; private CallbackMessageHandler mCallback; private VolumeProvider mVolumeProvider; private PlaybackState mPlaybackState; private boolean mActive = false; /** * Creates a new session. The session will automatically be registered with * the system but will not be published until {@link #setActive(boolean) * setActive(true)} is called. You must call {@link #release()} when * finished with the session. * * @param context The context to use to create the session. * @param tag A short name for debugging purposes. */ public MediaSession(@NonNull Context context, @NonNull String tag) { this(context, tag, UserHandle.myUserId()); } /** * Creates a new session as the specified user. To create a session as a * user other than your own you must hold the * {@link android.Manifest.permission#INTERACT_ACROSS_USERS_FULL} * permission. * * @param context The context to use to create the session. * @param tag A short name for debugging purposes. * @param userId The user id to create the session as. * @hide */ public MediaSession(@NonNull Context context, @NonNull String tag, int userId) { if (context == null) { throw new IllegalArgumentException("context cannot be null."); } if (TextUtils.isEmpty(tag)) { throw new IllegalArgumentException("tag cannot be null or empty"); } mMaxBitmapSize = context.getResources().getDimensionPixelSize( com.android.internal.R.dimen.config_mediaMetadataBitmapMaxSize); mCbStub = new CallbackStub(this); MediaSessionManager manager = (MediaSessionManager) context .getSystemService(Context.MEDIA_SESSION_SERVICE); try { mBinder = manager.createSession(mCbStub, tag, userId); mSessionToken = new Token(mBinder.getController()); mController = new MediaController(context, mSessionToken); } catch (RemoteException e) { throw new RuntimeException("Remote error creating session.", e); } } /** * Set the callback to receive updates for the MediaSession. This includes * media button events and transport controls. The caller's thread will be * used to post updates. *
* Set the callback to null to stop receiving updates. * * @param callback The callback object */ public void setCallback(@Nullable Callback callback) { setCallback(callback, null); } /** * Set the callback to receive updates for the MediaSession. This includes * media button events and transport controls. *
* Set the callback to null to stop receiving updates. * * @param callback The callback to receive updates on. * @param handler The handler that events should be posted on. */ public void setCallback(@Nullable Callback callback, @Nullable Handler handler) { synchronized (mLock) { if (callback == null) { if (mCallback != null) { mCallback.mCallback.mSession = null; } mCallback = null; return; } if (mCallback != null) { // We're updating the callback, clear the session from the old // one. mCallback.mCallback.mSession = null; } if (handler == null) { handler = new Handler(); } callback.mSession = this; CallbackMessageHandler msgHandler = new CallbackMessageHandler(handler.getLooper(), callback); mCallback = msgHandler; } } /** * Set an intent for launching UI for this Session. This can be used as a * quick link to an ongoing media screen. The intent should be for an * activity that may be started using {@link Activity#startActivity(Intent)}. * * @param pi The intent to launch to show UI for this Session. */ public void setSessionActivity(@Nullable PendingIntent pi) { try { mBinder.setLaunchPendingIntent(pi); } catch (RemoteException e) { Log.wtf(TAG, "Failure in setLaunchPendingIntent.", e); } } /** * Set a pending intent for your media button receiver to allow restarting * playback after the session has been stopped. If your app is started in * this way an {@link Intent#ACTION_MEDIA_BUTTON} intent will be sent via * the pending intent. * * @param mbr The {@link PendingIntent} to send the media button event to. */ public void setMediaButtonReceiver(@Nullable PendingIntent mbr) { try { mBinder.setMediaButtonReceiver(mbr); } catch (RemoteException e) { Log.wtf(TAG, "Failure in setMediaButtonReceiver.", e); } } /** * Set any flags for the session. * * @param flags The flags to set for this session. */ public void setFlags(@SessionFlags int flags) { try { mBinder.setFlags(flags); } catch (RemoteException e) { Log.wtf(TAG, "Failure in setFlags.", e); } } /** * Set the attributes for this session's audio. This will affect the * system's volume handling for this session. If * {@link #setPlaybackToRemote} was previously called it will stop receiving * volume commands and the system will begin sending volume changes to the * appropriate stream. *
* By default sessions use attributes for media. * * @param attributes The {@link AudioAttributes} for this session's audio. */ public void setPlaybackToLocal(AudioAttributes attributes) { if (attributes == null) { throw new IllegalArgumentException("Attributes cannot be null for local playback."); } try { mBinder.setPlaybackToLocal(attributes); } catch (RemoteException e) { Log.wtf(TAG, "Failure in setPlaybackToLocal.", e); } } /** * Configure this session to use remote volume handling. This must be called * to receive volume button events, otherwise the system will adjust the * appropriate stream volume for this session. If * {@link #setPlaybackToLocal} was previously called the system will stop * handling volume changes for this session and pass them to the volume * provider instead. * * @param volumeProvider The provider that will handle volume changes. May * not be null. */ public void setPlaybackToRemote(@NonNull VolumeProvider volumeProvider) { if (volumeProvider == null) { throw new IllegalArgumentException("volumeProvider may not be null!"); } synchronized (mLock) { mVolumeProvider = volumeProvider; } volumeProvider.setCallback(new VolumeProvider.Callback() { @Override public void onVolumeChanged(VolumeProvider volumeProvider) { notifyRemoteVolumeChanged(volumeProvider); } }); try { mBinder.setPlaybackToRemote(volumeProvider.getVolumeControl(), volumeProvider.getMaxVolume()); mBinder.setCurrentVolume(volumeProvider.getCurrentVolume()); } catch (RemoteException e) { Log.wtf(TAG, "Failure in setPlaybackToRemote.", e); } } /** * Set if this session is currently active and ready to receive commands. If * set to false your session's controller may not be discoverable. You must * set the session to active before it can start receiving media button * events or transport commands. * * @param active Whether this session is active or not. */ public void setActive(boolean active) { if (mActive == active) { return; } try { mBinder.setActive(active); mActive = active; } catch (RemoteException e) { Log.wtf(TAG, "Failure in setActive.", e); } } /** * Get the current active state of this session. * * @return True if the session is active, false otherwise. */ public boolean isActive() { return mActive; } /** * Send a proprietary event to all MediaControllers listening to this * Session. It's up to the Controller/Session owner to determine the meaning * of any events. * * @param event The name of the event to send * @param extras Any extras included with the event */ public void sendSessionEvent(@NonNull String event, @Nullable Bundle extras) { if (TextUtils.isEmpty(event)) { throw new IllegalArgumentException("event cannot be null or empty"); } try { mBinder.sendEvent(event, extras); } catch (RemoteException e) { Log.wtf(TAG, "Error sending event", e); } } /** * This must be called when an app has finished performing playback. If * playback is expected to start again shortly the session can be left open, * but it must be released if your activity or service is being destroyed. */ public void release() { try { mBinder.destroy(); } catch (RemoteException e) { Log.wtf(TAG, "Error releasing session: ", e); } } /** * Retrieve a token object that can be used by apps to create a * {@link MediaController} for interacting with this session. The owner of * the session is responsible for deciding how to distribute these tokens. * * @return A token that can be used to create a MediaController for this * session */ public @NonNull Token getSessionToken() { return mSessionToken; } /** * Get a controller for this session. This is a convenience method to avoid * having to cache your own controller in process. * * @return A controller for this session. */ public @NonNull MediaController getController() { return mController; } /** * Update the current playback state. * * @param state The current state of playback */ public void setPlaybackState(@Nullable PlaybackState state) { mPlaybackState = state; try { mBinder.setPlaybackState(state); } catch (RemoteException e) { Log.wtf(TAG, "Dead object in setPlaybackState.", e); } } /** * Update the current metadata. New metadata can be created using * {@link android.media.MediaMetadata.Builder}. * * @param metadata The new metadata */ public void setMetadata(@Nullable MediaMetadata metadata) { if (metadata != null ) { metadata = (new MediaMetadata.Builder(metadata, mMaxBitmapSize)).build(); } try { mBinder.setMetadata(metadata); } catch (RemoteException e) { Log.wtf(TAG, "Dead object in setPlaybackState.", e); } } /** * Update the list of items in the play queue. It is an ordered list and * should contain the current item, and previous or upcoming items if they * exist. Specify null if there is no current play queue. *
* The queue should be of reasonable size. If the play queue is unbounded
* within your app, it is better to send a reasonable amount in a sliding
* window instead.
*
* @param queue A list of items in the play queue.
*/
public void setQueue(@Nullable List
* The intent will be of type {@link Intent#ACTION_MEDIA_BUTTON} with a
* KeyEvent in {@link Intent#EXTRA_KEY_EVENT}
*
* @param mediaButtonIntent an intent containing the KeyEvent as an
* extra
* @return True if the event was handled, false otherwise.
*/
public boolean onMediaButtonEvent(@NonNull Intent mediaButtonIntent) {
if (mSession != null
&& Intent.ACTION_MEDIA_BUTTON.equals(mediaButtonIntent.getAction())) {
KeyEvent ke = mediaButtonIntent.getParcelableExtra(Intent.EXTRA_KEY_EVENT);
if (ke != null && ke.getAction() == KeyEvent.ACTION_DOWN) {
PlaybackState state = mSession.mPlaybackState;
long validActions = state == null ? 0 : state.getActions();
switch (ke.getKeyCode()) {
case KeyEvent.KEYCODE_MEDIA_PLAY:
if ((validActions & PlaybackState.ACTION_PLAY) != 0) {
onPlay();
return true;
}
break;
case KeyEvent.KEYCODE_MEDIA_PAUSE:
if ((validActions & PlaybackState.ACTION_PAUSE) != 0) {
onPause();
return true;
}
break;
case KeyEvent.KEYCODE_MEDIA_NEXT:
if ((validActions & PlaybackState.ACTION_SKIP_TO_NEXT) != 0) {
onSkipToNext();
return true;
}
break;
case KeyEvent.KEYCODE_MEDIA_PREVIOUS:
if ((validActions & PlaybackState.ACTION_SKIP_TO_PREVIOUS) != 0) {
onSkipToPrevious();
return true;
}
break;
case KeyEvent.KEYCODE_MEDIA_STOP:
if ((validActions & PlaybackState.ACTION_STOP) != 0) {
onStop();
return true;
}
break;
case KeyEvent.KEYCODE_MEDIA_FAST_FORWARD:
if ((validActions & PlaybackState.ACTION_FAST_FORWARD) != 0) {
onFastForward();
return true;
}
break;
case KeyEvent.KEYCODE_MEDIA_REWIND:
if ((validActions & PlaybackState.ACTION_REWIND) != 0) {
onRewind();
return true;
}
break;
case KeyEvent.KEYCODE_MEDIA_PLAY_PAUSE:
case KeyEvent.KEYCODE_HEADSETHOOK:
boolean isPlaying = state == null ? false
: state.getState() == PlaybackState.STATE_PLAYING;
boolean canPlay = (validActions & (PlaybackState.ACTION_PLAY_PAUSE
| PlaybackState.ACTION_PLAY)) != 0;
boolean canPause = (validActions & (PlaybackState.ACTION_PLAY_PAUSE
| PlaybackState.ACTION_PAUSE)) != 0;
if (isPlaying && canPause) {
onPause();
return true;
} else if (!isPlaying && canPlay) {
onPlay();
return true;
}
break;
}
}
}
return false;
}
/**
* Override to handle requests to prepare playback. During the preparation, a session should
* not hold audio focus in order to allow other sessions play seamlessly. The state of
* playback should be updated to {@link PlaybackState#STATE_PAUSED} after the preparation is
* done.
*/
public void onPrepare() {
}
/**
* Override to handle requests to prepare for playing a specific mediaId that was provided
* by your app's {@link MediaBrowserService}. During the preparation, a session should not
* hold audio focus in order to allow other sessions play seamlessly. The state of playback
* should be updated to {@link PlaybackState#STATE_PAUSED} after the preparation is done.
* The playback of the prepared content should start in the implementation of
* {@link #onPlay}. Override {@link #onPlayFromMediaId} to handle requests for starting
* playback without preparation.
*/
public void onPrepareFromMediaId(String mediaId, Bundle extras) {
}
/**
* Override to handle requests to prepare playback from a search query. An empty query
* indicates that the app may prepare any music. The implementation should attempt to make a
* smart choice about what to play. During the preparation, a session should not hold audio
* focus in order to allow other sessions play seamlessly. The state of playback should be
* updated to {@link PlaybackState#STATE_PAUSED} after the preparation is done. The playback
* of the prepared content should start in the implementation of {@link #onPlay}. Override
* {@link #onPlayFromSearch} to handle requests for starting playback without preparation.
*/
public void onPrepareFromSearch(String query, Bundle extras) {
}
/**
* Override to handle requests to prepare a specific media item represented by a URI.
* During the preparation, a session should not hold audio focus in order to allow
* other sessions play seamlessly. The state of playback should be updated to
* {@link PlaybackState#STATE_PAUSED} after the preparation is done.
* The playback of the prepared content should start in the implementation of
* {@link #onPlay}. Override {@link #onPlayFromUri} to handle requests
* for starting playback without preparation.
*/
public void onPrepareFromUri(Uri uri, Bundle extras) {
}
/**
* Override to handle requests to begin playback.
*/
public void onPlay() {
}
/**
* Override to handle requests to begin playback from a search query. An
* empty query indicates that the app may play any music. The
* implementation should attempt to make a smart choice about what to
* play.
*/
public void onPlayFromSearch(String query, Bundle extras) {
}
/**
* Override to handle requests to play a specific mediaId that was
* provided by your app's {@link MediaBrowserService}.
*/
public void onPlayFromMediaId(String mediaId, Bundle extras) {
}
/**
* Override to handle requests to play a specific media item represented by a URI.
*/
public void onPlayFromUri(Uri uri, Bundle extras) {
}
/**
* Override to handle requests to play an item with a given id from the
* play queue.
*/
public void onSkipToQueueItem(long id) {
}
/**
* Override to handle requests to pause playback.
*/
public void onPause() {
}
/**
* Override to handle requests to skip to the next media item.
*/
public void onSkipToNext() {
}
/**
* Override to handle requests to skip to the previous media item.
*/
public void onSkipToPrevious() {
}
/**
* Override to handle requests to fast forward.
*/
public void onFastForward() {
}
/**
* Override to handle requests to rewind.
*/
public void onRewind() {
}
/**
* Override to handle requests to stop playback.
*/
public void onStop() {
}
/**
* Override to handle requests to seek to a specific position in ms.
*
* @param pos New position to move to, in milliseconds.
*/
public void onSeekTo(long pos) {
}
/**
* Override to handle the item being rated.
*
* @param rating
*/
public void onSetRating(@NonNull Rating rating) {
}
/**
* Called when a {@link MediaController} wants a {@link PlaybackState.CustomAction} to be
* performed.
*
* @param action The action that was originally sent in the
* {@link PlaybackState.CustomAction}.
* @param extras Optional extras specified by the {@link MediaController}.
*/
public void onCustomAction(@NonNull String action, @Nullable Bundle extras) {
}
}
/**
* @hide
*/
public static class CallbackStub extends ISessionCallback.Stub {
private WeakReference
*
*/
public void setRatingType(@Rating.Style int type) {
try {
mBinder.setRatingType(type);
} catch (RemoteException e) {
Log.e(TAG, "Error in setRatingType.", e);
}
}
/**
* Set some extras that can be associated with the {@link MediaSession}. No assumptions should
* be made as to how a {@link MediaController} will handle these extras.
* Keys should be fully qualified (e.g. com.example.MY_EXTRA) to avoid conflicts.
*
* @param extras The extras associated with the {@link MediaSession}.
*/
public void setExtras(@Nullable Bundle extras) {
try {
mBinder.setExtras(extras);
} catch (RemoteException e) {
Log.wtf("Dead object in setExtras.", e);
}
}
/**
* Notify the system that the remote volume changed.
*
* @param provider The provider that is handling volume changes.
* @hide
*/
public void notifyRemoteVolumeChanged(VolumeProvider provider) {
synchronized (mLock) {
if (provider == null || provider != mVolumeProvider) {
Log.w(TAG, "Received update from stale volume provider");
return;
}
}
try {
mBinder.setCurrentVolume(provider.getCurrentVolume());
} catch (RemoteException e) {
Log.e(TAG, "Error in notifyVolumeChanged", e);
}
}
/**
* Returns the name of the package that sent the last media button, transport control, or
* command from controllers and the system. This is only valid while in a request callback, such
* as {@link Callback#onPlay}.
*
* @hide
*/
public String getCallingPackage() {
try {
return mBinder.getCallingPackage();
} catch (RemoteException e) {
Log.wtf(TAG, "Dead object in getCallingPackage.", e);
}
return null;
}
private void dispatchPrepare() {
postToCallback(CallbackMessageHandler.MSG_PREPARE);
}
private void dispatchPrepareFromMediaId(String mediaId, Bundle extras) {
postToCallback(CallbackMessageHandler.MSG_PREPARE_MEDIA_ID, mediaId, extras);
}
private void dispatchPrepareFromSearch(String query, Bundle extras) {
postToCallback(CallbackMessageHandler.MSG_PREPARE_SEARCH, query, extras);
}
private void dispatchPrepareFromUri(Uri uri, Bundle extras) {
postToCallback(CallbackMessageHandler.MSG_PREPARE_URI, uri, extras);
}
private void dispatchPlay() {
postToCallback(CallbackMessageHandler.MSG_PLAY);
}
private void dispatchPlayFromMediaId(String mediaId, Bundle extras) {
postToCallback(CallbackMessageHandler.MSG_PLAY_MEDIA_ID, mediaId, extras);
}
private void dispatchPlayFromSearch(String query, Bundle extras) {
postToCallback(CallbackMessageHandler.MSG_PLAY_SEARCH, query, extras);
}
private void dispatchPlayFromUri(Uri uri, Bundle extras) {
postToCallback(CallbackMessageHandler.MSG_PLAY_URI, uri, extras);
}
private void dispatchSkipToItem(long id) {
postToCallback(CallbackMessageHandler.MSG_SKIP_TO_ITEM, id);
}
private void dispatchPause() {
postToCallback(CallbackMessageHandler.MSG_PAUSE);
}
private void dispatchStop() {
postToCallback(CallbackMessageHandler.MSG_STOP);
}
private void dispatchNext() {
postToCallback(CallbackMessageHandler.MSG_NEXT);
}
private void dispatchPrevious() {
postToCallback(CallbackMessageHandler.MSG_PREVIOUS);
}
private void dispatchFastForward() {
postToCallback(CallbackMessageHandler.MSG_FAST_FORWARD);
}
private void dispatchRewind() {
postToCallback(CallbackMessageHandler.MSG_REWIND);
}
private void dispatchSeekTo(long pos) {
postToCallback(CallbackMessageHandler.MSG_SEEK_TO, pos);
}
private void dispatchRate(Rating rating) {
postToCallback(CallbackMessageHandler.MSG_RATE, rating);
}
private void dispatchCustomAction(String action, Bundle args) {
postToCallback(CallbackMessageHandler.MSG_CUSTOM_ACTION, action, args);
}
private void dispatchMediaButton(Intent mediaButtonIntent) {
postToCallback(CallbackMessageHandler.MSG_MEDIA_BUTTON, mediaButtonIntent);
}
private void dispatchAdjustVolume(int direction) {
postToCallback(CallbackMessageHandler.MSG_ADJUST_VOLUME, direction);
}
private void dispatchSetVolumeTo(int volume) {
postToCallback(CallbackMessageHandler.MSG_SET_VOLUME, volume);
}
private void postToCallback(int what) {
postToCallback(what, null);
}
private void postCommand(String command, Bundle args, ResultReceiver resultCb) {
Command cmd = new Command(command, args, resultCb);
postToCallback(CallbackMessageHandler.MSG_COMMAND, cmd);
}
private void postToCallback(int what, Object obj) {
postToCallback(what, obj, null);
}
private void postToCallback(int what, Object obj, Bundle extras) {
synchronized (mLock) {
if (mCallback != null) {
mCallback.post(what, obj, extras);
}
}
}
/**
* Return true if this is considered an active playback state.
*
* @hide
*/
public static boolean isActiveState(int state) {
switch (state) {
case PlaybackState.STATE_FAST_FORWARDING:
case PlaybackState.STATE_REWINDING:
case PlaybackState.STATE_SKIPPING_TO_PREVIOUS:
case PlaybackState.STATE_SKIPPING_TO_NEXT:
case PlaybackState.STATE_BUFFERING:
case PlaybackState.STATE_CONNECTING:
case PlaybackState.STATE_PLAYING:
return true;
}
return false;
}
/**
* Represents an ongoing session. This may be passed to apps by the session
* owner to allow them to create a {@link MediaController} to communicate with
* the session.
*/
public static final class Token implements Parcelable {
private ISessionController mBinder;
/**
* @hide
*/
public Token(ISessionController binder) {
mBinder = binder;
}
@Override
public int describeContents() {
return 0;
}
@Override
public void writeToParcel(Parcel dest, int flags) {
dest.writeStrongBinder(mBinder.asBinder());
}
@Override
public int hashCode() {
final int prime = 31;
int result = 1;
result = prime * result + ((mBinder == null) ? 0 : mBinder.asBinder().hashCode());
return result;
}
@Override
public boolean equals(Object obj) {
if (this == obj)
return true;
if (obj == null)
return false;
if (getClass() != obj.getClass())
return false;
Token other = (Token) obj;
if (mBinder == null) {
if (other.mBinder != null)
return false;
} else if (!mBinder.asBinder().equals(other.mBinder.asBinder()))
return false;
return true;
}
ISessionController getBinder() {
return mBinder;
}
public static final Parcelable.Creator