MediaLibraryService.MediaLibrarySession.Callback

default ListenableFuture<LibraryResult<ImmutableList<MediaItem>>> onGetChildren(
    MediaLibraryService.MediaLibrarySession session,
    MediaSession.ControllerInfo browser,
    String parentId,
    @IntRange(from = 0) int page,
    @IntRange(from = 1) int pageSize,
    @Nullable MediaLibraryService.LibraryParams params
)

Called when a MediaBrowser requests the child media items of the given parent id by getChildren.

Return a ListenableFuture to send a LibraryResult back to the browser asynchronously. You can also return a LibraryResult directly by using Guava's immediateFuture.

The params should be the same as the given params.

To allow getting the children, return a LibraryResult with RESULT_SUCCESS and a list of media items. Return an empty list for no children rather than using error codes.

default ListenableFuture<LibraryResult<MediaItem>> onGetItem(
    MediaLibraryService.MediaLibrarySession session,
    MediaSession.ControllerInfo browser,
    String mediaId
)

Called when a MediaBrowser requests a MediaItem by getItem.

Return a ListenableFuture to send a LibraryResult back to the browser asynchronously. You can also return a LibraryResult directly by using Guava's immediateFuture.

To allow getting the item, return a LibraryResult with RESULT_SUCCESS and a MediaItem with a valid mediaId.

default ListenableFuture<LibraryResult<MediaItem>> onGetLibraryRoot(
    MediaLibraryService.MediaLibrarySession session,
    MediaSession.ControllerInfo browser,
    @Nullable MediaLibraryService.LibraryParams params
)

Called when a MediaBrowser requests the root MediaItem by getLibraryRoot.

Return a ListenableFuture to send a LibraryResult back to the browser asynchronously. You can also return a LibraryResult directly by using Guava's immediateFuture.

The params may differ from the given params if the session can't provide a root that matches with the params.

To allow browsing the media library, return a LibraryResult with RESULT_SUCCESS and a root MediaItem with a valid mediaId. The media id is required for the browser to get the children under the root.

Interoperability: If this callback is called because a legacy android.support.v4.media.MediaBrowserCompat has requested a androidx.media.MediaBrowserServiceCompat.BrowserRoot, then the main thread may be blocked until the returned future is done. If your service may be queried by a legacy android.support.v4.media.MediaBrowserCompat, you should ensure that the future completes quickly to avoid blocking the main thread for a long period of time.

default ListenableFuture<LibraryResult<ImmutableList<MediaItem>>> onGetSearchResult(
    MediaLibraryService.MediaLibrarySession session,
    MediaSession.ControllerInfo browser,
    String query,
    @IntRange(from = 0) int page,
    @IntRange(from = 1) int pageSize,
    @Nullable MediaLibraryService.LibraryParams params
)

Called when a MediaBrowser requests a search result with getSearchResult.

Return a ListenableFuture to send a LibraryResult back to the browser asynchronously. You can also return a LibraryResult directly by using Guava's immediateFuture.

The params should be the same as the given params.

To allow getting the search result, return a LibraryResult with RESULT_SUCCESS and a list of media items. Return an empty list for no children rather than using error codes.

Typically, the query is requested through onSearch before, but it may not especially when android.support.v4.media.MediaBrowserCompat.search() is used.

default ListenableFuture<LibraryResult<Void>> onSearch(
    MediaLibraryService.MediaLibrarySession session,
    MediaSession.ControllerInfo browser,
    String query,
    @Nullable MediaLibraryService.LibraryParams params
)

Called when a MediaBrowser requests a search with search.

Return a ListenableFuture to send a LibraryResult back to the browser asynchronously. You can also return a LibraryResult directly by using Guava's immediateFuture.

The params should be the same as the given params.

Return LibraryResult with a result code for the search and notify the number of search result (media items) through notifySearchResultChanged. will ask the search result afterwards through onGetSearchResult.

default ListenableFuture<LibraryResult<Void>> onSubscribe(
    MediaLibraryService.MediaLibrarySession session,
    MediaSession.ControllerInfo browser,
    String parentId,
    @Nullable MediaLibraryService.LibraryParams params
)

Called when a MediaBrowser subscribes to the given parent id by subscribe.

See getSubscribedControllers also.

By default, the library calls onGetItem for the parentId that the browser requests to subscribe to. If onGetItem returns RESULT_SUCCESS with a browsable item, the subscription is accepted and notifyChildrenChanged is immediately called with an itemCount of MAX_VALUE. In all other cases, the subscription is rejected and a result value different to RESULT_SUCCESS is returned from this method.

To implement a different behavior, an app can safely override this method without calling super. Return a result code RESULT_SUCCESS to accept the subscription, or return a result different to RESULT_SUCCESS to prevent controllers from subscribing.

Return a ListenableFuture to send a LibraryResult back to the browser asynchronously. You can also return a LibraryResult directly by using Guava's immediateFuture.

The params returned to the caller should be the same as the params passed into this method.

Interoperability: This will be called by android.support.v4.media.MediaBrowserCompat.subscribe(), but won't be called by subscribe.

default ListenableFuture<LibraryResult<Void>> onUnsubscribe(
    MediaLibraryService.MediaLibrarySession session,
    MediaSession.ControllerInfo browser,
    String parentId
)

Called when a MediaBrowser unsubscribes from the given parent ID by unsubscribe.

Return a ListenableFuture to send a LibraryResult back to the browser asynchronously. You can also return a LibraryResult directly by using Guava's immediateFuture.

Apps normally don't need to implement this method, because the library maintains the subscribed controllers internally and an app can use getSubscribedControllers to get subscribed controllers for which to call notifyChildrenChanged.

Interoperability: This will be called by android.support.v4.media.MediaBrowserCompat.unsubscribe(), but won't be called by unsubscribe.