Java tutorial
/* * Copyright (C) 2014 The Android Open Source Project * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ package android.media.browse; import android.annotation.IntDef; import android.annotation.NonNull; import android.annotation.Nullable; import android.content.ComponentName; import android.content.Context; import android.content.Intent; import android.content.ServiceConnection; import android.content.pm.ParceledListSlice; import android.media.MediaDescription; import android.media.session.MediaController; import android.media.session.MediaSession; import android.os.Binder; import android.os.Bundle; import android.os.Handler; import android.os.IBinder; import android.os.Parcel; import android.os.Parcelable; import android.os.RemoteException; import android.os.ResultReceiver; import android.service.media.IMediaBrowserService; import android.service.media.IMediaBrowserServiceCallbacks; import android.service.media.MediaBrowserService; import android.text.TextUtils; import android.util.ArrayMap; import android.util.Log; import java.lang.annotation.Retention; import java.lang.annotation.RetentionPolicy; import java.lang.ref.WeakReference; import java.util.ArrayList; import java.util.List; import java.util.Map.Entry; /** * Browses media content offered by a link MediaBrowserService. * <p> * This object is not thread-safe. All calls should happen on the thread on which the browser * was constructed. * </p> * <h3>Standard Extra Data</h3> * * <p>These are the current standard fields that can be used as extra data via * {@link #subscribe(String, Bundle, SubscriptionCallback)}, * {@link #unsubscribe(String, SubscriptionCallback)}, and * {@link SubscriptionCallback#onChildrenLoaded(String, List, Bundle)}. * * <ul> * <li> {@link #EXTRA_PAGE} * <li> {@link #EXTRA_PAGE_SIZE} * </ul> */ public final class MediaBrowser { private static final String TAG = "MediaBrowser"; private static final boolean DBG = false; /** * Used as an int extra field to denote the page number to subscribe. * The value of {@code EXTRA_PAGE} should be greater than or equal to 0. * * @see #EXTRA_PAGE_SIZE */ public static final String EXTRA_PAGE = "android.media.browse.extra.PAGE"; /** * Used as an int extra field to denote the number of media items in a page. * The value of {@code EXTRA_PAGE_SIZE} should be greater than or equal to 1. * * @see #EXTRA_PAGE */ public static final String EXTRA_PAGE_SIZE = "android.media.browse.extra.PAGE_SIZE"; private static final int CONNECT_STATE_DISCONNECTING = 0; private static final int CONNECT_STATE_DISCONNECTED = 1; private static final int CONNECT_STATE_CONNECTING = 2; private static final int CONNECT_STATE_CONNECTED = 3; private static final int CONNECT_STATE_SUSPENDED = 4; private final Context mContext; private final ComponentName mServiceComponent; private final ConnectionCallback mCallback; private final Bundle mRootHints; private final Handler mHandler = new Handler(); private final ArrayMap<String, Subscription> mSubscriptions = new ArrayMap<>(); private volatile int mState = CONNECT_STATE_DISCONNECTED; private volatile String mRootId; private volatile MediaSession.Token mMediaSessionToken; private volatile Bundle mExtras; private MediaServiceConnection mServiceConnection; private IMediaBrowserService mServiceBinder; private IMediaBrowserServiceCallbacks mServiceCallbacks; /** * Creates a media browser for the specified media browser service. * * @param context The context. * @param serviceComponent The component name of the media browser service. * @param callback The connection callback. * @param rootHints An optional bundle of service-specific arguments to send * to the media browser service when connecting and retrieving the root id * for browsing, or null if none. The contents of this bundle may affect * the information returned when browsing. * @see android.service.media.MediaBrowserService.BrowserRoot#EXTRA_RECENT * @see android.service.media.MediaBrowserService.BrowserRoot#EXTRA_OFFLINE * @see android.service.media.MediaBrowserService.BrowserRoot#EXTRA_SUGGESTED */ public MediaBrowser(Context context, ComponentName serviceComponent, ConnectionCallback callback, Bundle rootHints) { if (context == null) { throw new IllegalArgumentException("context must not be null"); } if (serviceComponent == null) { throw new IllegalArgumentException("service component must not be null"); } if (callback == null) { throw new IllegalArgumentException("connection callback must not be null"); } mContext = context; mServiceComponent = serviceComponent; mCallback = callback; mRootHints = rootHints == null ? null : new Bundle(rootHints); } /** * Connects to the media browser service. * <p> * The connection callback specified in the constructor will be invoked * when the connection completes or fails. * </p> */ public void connect() { if (mState != CONNECT_STATE_DISCONNECTING && mState != CONNECT_STATE_DISCONNECTED) { throw new IllegalStateException("connect() called while neither disconnecting nor " + "disconnected (state=" + getStateLabel(mState) + ")"); } mState = CONNECT_STATE_CONNECTING; mHandler.post(new Runnable() { @Override public void run() { if (mState == CONNECT_STATE_DISCONNECTING) { return; } mState = CONNECT_STATE_CONNECTING; // TODO: remove this extra check. if (DBG) { if (mServiceConnection != null) { throw new RuntimeException( "mServiceConnection should be null. Instead it" + " is " + mServiceConnection); } } if (mServiceBinder != null) { throw new RuntimeException("mServiceBinder should be null. Instead it is " + mServiceBinder); } if (mServiceCallbacks != null) { throw new RuntimeException( "mServiceCallbacks should be null. Instead it is " + mServiceCallbacks); } final Intent intent = new Intent(MediaBrowserService.SERVICE_INTERFACE); intent.setComponent(mServiceComponent); mServiceConnection = new MediaServiceConnection(); boolean bound = false; try { bound = mContext.bindService(intent, mServiceConnection, Context.BIND_AUTO_CREATE); } catch (Exception ex) { Log.e(TAG, "Failed binding to service " + mServiceComponent); } if (!bound) { // Tell them that it didn't work. forceCloseConnection(); mCallback.onConnectionFailed(); } if (DBG) { Log.d(TAG, "connect..."); dump(); } } }); } /** * Disconnects from the media browser service. * After this, no more callbacks will be received. */ public void disconnect() { // It's ok to call this any state, because allowing this lets apps not have // to check isConnected() unnecessarily. They won't appreciate the extra // assertions for this. We do everything we can here to go back to a sane state. mState = CONNECT_STATE_DISCONNECTING; mHandler.post(new Runnable() { @Override public void run() { // connect() could be called before this. Then we will disconnect and reconnect. if (mServiceCallbacks != null) { try { mServiceBinder.disconnect(mServiceCallbacks); } catch (RemoteException ex) { // We are disconnecting anyway. Log, just for posterity but it's not // a big problem. Log.w(TAG, "RemoteException during connect for " + mServiceComponent); } } int state = mState; forceCloseConnection(); // If the state was not CONNECT_STATE_DISCONNECTING, keep the state so that // the operation came after disconnect() can be handled properly. if (state != CONNECT_STATE_DISCONNECTING) { mState = state; } if (DBG) { Log.d(TAG, "disconnect..."); dump(); } } }); } /** * Null out the variables and unbind from the service. This doesn't include * calling disconnect on the service, because we only try to do that in the * clean shutdown cases. * <p> * Everywhere that calls this EXCEPT for disconnect() should follow it with * a call to mCallback.onConnectionFailed(). Disconnect doesn't do that callback * for a clean shutdown, but everywhere else is a dirty shutdown and should * notify the app. * <p> * Also, mState should be updated properly. Mostly it should be CONNECT_STATE_DIACONNECTED * except for disconnect(). */ private void forceCloseConnection() { if (mServiceConnection != null) { try { mContext.unbindService(mServiceConnection); } catch (IllegalArgumentException e) { if (DBG) { Log.d(TAG, "unbindService failed", e); } } } mState = CONNECT_STATE_DISCONNECTED; mServiceConnection = null; mServiceBinder = null; mServiceCallbacks = null; mRootId = null; mMediaSessionToken = null; } /** * Returns whether the browser is connected to the service. */ public boolean isConnected() { return mState == CONNECT_STATE_CONNECTED; } /** * Gets the service component that the media browser is connected to. */ public @NonNull ComponentName getServiceComponent() { if (!isConnected()) { throw new IllegalStateException( "getServiceComponent() called while not connected" + " (state=" + mState + ")"); } return mServiceComponent; } /** * Gets the root id. * <p> * Note that the root id may become invalid or change when the * browser is disconnected. * </p> * * @throws IllegalStateException if not connected. */ public @NonNull String getRoot() { if (!isConnected()) { throw new IllegalStateException( "getRoot() called while not connected (state=" + getStateLabel(mState) + ")"); } return mRootId; } /** * Gets any extras for the media service. * * @throws IllegalStateException if not connected. */ public @Nullable Bundle getExtras() { if (!isConnected()) { throw new IllegalStateException( "getExtras() called while not connected (state=" + getStateLabel(mState) + ")"); } return mExtras; } /** * Gets the media session token associated with the media browser. * <p> * Note that the session token may become invalid or change when the * browser is disconnected. * </p> * * @return The session token for the browser, never null. * * @throws IllegalStateException if not connected. */ public @NonNull MediaSession.Token getSessionToken() { if (!isConnected()) { throw new IllegalStateException("getSessionToken() called while not connected (state=" + mState + ")"); } return mMediaSessionToken; } /** * Queries for information about the media items that are contained within * the specified id and subscribes to receive updates when they change. * <p> * The list of subscriptions is maintained even when not connected and is * restored after the reconnection. It is ok to subscribe while not connected * but the results will not be returned until the connection completes. * </p> * <p> * If the id is already subscribed with a different callback then the new * callback will replace the previous one and the child data will be * reloaded. * </p> * * @param parentId The id of the parent media item whose list of children * will be subscribed. * @param callback The callback to receive the list of children. */ public void subscribe(@NonNull String parentId, @NonNull SubscriptionCallback callback) { subscribeInternal(parentId, null, callback); } /** * Queries with service-specific arguments for information about the media items * that are contained within the specified id and subscribes to receive updates * when they change. * <p> * The list of subscriptions is maintained even when not connected and is * restored after the reconnection. It is ok to subscribe while not connected * but the results will not be returned until the connection completes. * </p> * <p> * If the id is already subscribed with a different callback then the new * callback will replace the previous one and the child data will be * reloaded. * </p> * * @param parentId The id of the parent media item whose list of children * will be subscribed. * @param options The bundle of service-specific arguments to send to the media * browser service. The contents of this bundle may affect the * information returned when browsing. * @param callback The callback to receive the list of children. */ public void subscribe(@NonNull String parentId, @NonNull Bundle options, @NonNull SubscriptionCallback callback) { if (options == null) { throw new IllegalArgumentException("options cannot be null"); } subscribeInternal(parentId, new Bundle(options), callback); } /** * Unsubscribes for changes to the children of the specified media id. * <p> * The query callback will no longer be invoked for results associated with * this id once this method returns. * </p> * * @param parentId The id of the parent media item whose list of children * will be unsubscribed. */ public void unsubscribe(@NonNull String parentId) { unsubscribeInternal(parentId, null); } /** * Unsubscribes for changes to the children of the specified media id through a callback. * <p> * The query callback will no longer be invoked for results associated with * this id once this method returns. * </p> * * @param parentId The id of the parent media item whose list of children * will be unsubscribed. * @param callback A callback sent to the media browser service to subscribe. */ public void unsubscribe(@NonNull String parentId, @NonNull SubscriptionCallback callback) { if (callback == null) { throw new IllegalArgumentException("callback cannot be null"); } unsubscribeInternal(parentId, callback); } /** * Retrieves a specific {@link MediaItem} from the connected service. Not * all services may support this, so falling back to subscribing to the * parent's id should be used when unavailable. * * @param mediaId The id of the item to retrieve. * @param cb The callback to receive the result on. */ public void getItem(final @NonNull String mediaId, @NonNull final ItemCallback cb) { if (TextUtils.isEmpty(mediaId)) { throw new IllegalArgumentException("mediaId cannot be empty."); } if (cb == null) { throw new IllegalArgumentException("cb cannot be null."); } if (mState != CONNECT_STATE_CONNECTED) { Log.i(TAG, "Not connected, unable to retrieve the MediaItem."); mHandler.post(new Runnable() { @Override public void run() { cb.onError(mediaId); } }); return; } ResultReceiver receiver = new ResultReceiver(mHandler) { @Override protected void onReceiveResult(int resultCode, Bundle resultData) { if (!isConnected()) { return; } if (resultCode != 0 || resultData == null || !resultData.containsKey(MediaBrowserService.KEY_MEDIA_ITEM)) { cb.onError(mediaId); return; } Parcelable item = resultData.getParcelable(MediaBrowserService.KEY_MEDIA_ITEM); if (item != null && !(item instanceof MediaItem)) { cb.onError(mediaId); return; } cb.onItemLoaded((MediaItem) item); } }; try { mServiceBinder.getMediaItem(mediaId, receiver, mServiceCallbacks); } catch (RemoteException e) { Log.i(TAG, "Remote error getting media item."); mHandler.post(new Runnable() { @Override public void run() { cb.onError(mediaId); } }); } } private void subscribeInternal(String parentId, Bundle options, SubscriptionCallback callback) { // Check arguments. if (TextUtils.isEmpty(parentId)) { throw new IllegalArgumentException("parentId cannot be empty."); } if (callback == null) { throw new IllegalArgumentException("callback cannot be null"); } // Update or create the subscription. Subscription sub = mSubscriptions.get(parentId); if (sub == null) { sub = new Subscription(); mSubscriptions.put(parentId, sub); } sub.putCallback(mContext, options, callback); // If we are connected, tell the service that we are watching. If we aren't connected, // the service will be told when we connect. if (isConnected()) { try { if (options == null) { mServiceBinder.addSubscriptionDeprecated(parentId, mServiceCallbacks); } mServiceBinder.addSubscription(parentId, callback.mToken, options, mServiceCallbacks); } catch (RemoteException ex) { // Process is crashing. We will disconnect, and upon reconnect we will // automatically reregister. So nothing to do here. Log.d(TAG, "addSubscription failed with RemoteException parentId=" + parentId); } } } private void unsubscribeInternal(String parentId, SubscriptionCallback callback) { // Check arguments. if (TextUtils.isEmpty(parentId)) { throw new IllegalArgumentException("parentId cannot be empty."); } Subscription sub = mSubscriptions.get(parentId); if (sub == null) { return; } // Tell the service if necessary. try { if (callback == null) { if (isConnected()) { mServiceBinder.removeSubscriptionDeprecated(parentId, mServiceCallbacks); mServiceBinder.removeSubscription(parentId, null, mServiceCallbacks); } } else { final List<SubscriptionCallback> callbacks = sub.getCallbacks(); final List<Bundle> optionsList = sub.getOptionsList(); for (int i = callbacks.size() - 1; i >= 0; --i) { if (callbacks.get(i) == callback) { if (isConnected()) { mServiceBinder.removeSubscription(parentId, callback.mToken, mServiceCallbacks); } callbacks.remove(i); optionsList.remove(i); } } } } catch (RemoteException ex) { // Process is crashing. We will disconnect, and upon reconnect we will // automatically reregister. So nothing to do here. Log.d(TAG, "removeSubscription failed with RemoteException parentId=" + parentId); } if (sub.isEmpty() || callback == null) { mSubscriptions.remove(parentId); } } /** * For debugging. */ private static String getStateLabel(int state) { switch (state) { case CONNECT_STATE_DISCONNECTING: return "CONNECT_STATE_DISCONNECTING"; case CONNECT_STATE_DISCONNECTED: return "CONNECT_STATE_DISCONNECTED"; case CONNECT_STATE_CONNECTING: return "CONNECT_STATE_CONNECTING"; case CONNECT_STATE_CONNECTED: return "CONNECT_STATE_CONNECTED"; case CONNECT_STATE_SUSPENDED: return "CONNECT_STATE_SUSPENDED"; default: return "UNKNOWN/" + state; } } private final void onServiceConnected(final IMediaBrowserServiceCallbacks callback, final String root, final MediaSession.Token session, final Bundle extra) { mHandler.post(new Runnable() { @Override public void run() { // Check to make sure there hasn't been a disconnect or a different // ServiceConnection. if (!isCurrent(callback, "onConnect")) { return; } // Don't allow them to call us twice. if (mState != CONNECT_STATE_CONNECTING) { Log.w(TAG, "onConnect from service while mState=" + getStateLabel(mState) + "... ignoring"); return; } mRootId = root; mMediaSessionToken = session; mExtras = extra; mState = CONNECT_STATE_CONNECTED; if (DBG) { Log.d(TAG, "ServiceCallbacks.onConnect..."); dump(); } mCallback.onConnected(); // we may receive some subscriptions before we are connected, so re-subscribe // everything now for (Entry<String, Subscription> subscriptionEntry : mSubscriptions.entrySet()) { String id = subscriptionEntry.getKey(); Subscription sub = subscriptionEntry.getValue(); List<SubscriptionCallback> callbackList = sub.getCallbacks(); List<Bundle> optionsList = sub.getOptionsList(); for (int i = 0; i < callbackList.size(); ++i) { try { mServiceBinder.addSubscription(id, callbackList.get(i).mToken, optionsList.get(i), mServiceCallbacks); } catch (RemoteException ex) { // Process is crashing. We will disconnect, and upon reconnect we will // automatically reregister. So nothing to do here. Log.d(TAG, "addSubscription failed with RemoteException parentId=" + id); } } } } }); } private final void onConnectionFailed(final IMediaBrowserServiceCallbacks callback) { mHandler.post(new Runnable() { @Override public void run() { Log.e(TAG, "onConnectFailed for " + mServiceComponent); // Check to make sure there hasn't been a disconnect or a different // ServiceConnection. if (!isCurrent(callback, "onConnectFailed")) { return; } // Don't allow them to call us twice. if (mState != CONNECT_STATE_CONNECTING) { Log.w(TAG, "onConnect from service while mState=" + getStateLabel(mState) + "... ignoring"); return; } // Clean up forceCloseConnection(); // Tell the app. mCallback.onConnectionFailed(); } }); } private final void onLoadChildren(final IMediaBrowserServiceCallbacks callback, final String parentId, final ParceledListSlice list, final Bundle options) { mHandler.post(new Runnable() { @Override public void run() { // Check that there hasn't been a disconnect or a different // ServiceConnection. if (!isCurrent(callback, "onLoadChildren")) { return; } if (DBG) { Log.d(TAG, "onLoadChildren for " + mServiceComponent + " id=" + parentId); } // Check that the subscription is still subscribed. final Subscription subscription = mSubscriptions.get(parentId); if (subscription != null) { // Tell the app. SubscriptionCallback subscriptionCallback = subscription.getCallback(mContext, options); if (subscriptionCallback != null) { List<MediaItem> data = list == null ? null : list.getList(); if (options == null) { if (data == null) { subscriptionCallback.onError(parentId); } else { subscriptionCallback.onChildrenLoaded(parentId, data); } } else { if (data == null) { subscriptionCallback.onError(parentId, options); } else { subscriptionCallback.onChildrenLoaded(parentId, data, options); } } return; } } if (DBG) { Log.d(TAG, "onLoadChildren for id that isn't subscribed id=" + parentId); } } }); } /** * Return true if {@code callback} is the current ServiceCallbacks. Also logs if it's not. */ private boolean isCurrent(IMediaBrowserServiceCallbacks callback, String funcName) { if (mServiceCallbacks != callback || mState == CONNECT_STATE_DISCONNECTING || mState == CONNECT_STATE_DISCONNECTED) { if (mState != CONNECT_STATE_DISCONNECTING && mState != CONNECT_STATE_DISCONNECTED) { Log.i(TAG, funcName + " for " + mServiceComponent + " with mServiceConnection=" + mServiceCallbacks + " this=" + this); } return false; } return true; } private ServiceCallbacks getNewServiceCallbacks() { return new ServiceCallbacks(this); } /** * Log internal state. * @hide */ void dump() { Log.d(TAG, "MediaBrowser..."); Log.d(TAG, " mServiceComponent=" + mServiceComponent); Log.d(TAG, " mCallback=" + mCallback); Log.d(TAG, " mRootHints=" + mRootHints); Log.d(TAG, " mState=" + getStateLabel(mState)); Log.d(TAG, " mServiceConnection=" + mServiceConnection); Log.d(TAG, " mServiceBinder=" + mServiceBinder); Log.d(TAG, " mServiceCallbacks=" + mServiceCallbacks); Log.d(TAG, " mRootId=" + mRootId); Log.d(TAG, " mMediaSessionToken=" + mMediaSessionToken); } /** * A class with information on a single media item for use in browsing/searching media. * MediaItems are application dependent so we cannot guarantee that they contain the * right values. */ public static class MediaItem implements Parcelable { private final int mFlags; private final MediaDescription mDescription; /** @hide */ @Retention(RetentionPolicy.SOURCE) @IntDef(flag = true, value = { FLAG_BROWSABLE, FLAG_PLAYABLE }) public @interface Flags { } /** * Flag: Indicates that the item has children of its own. */ public static final int FLAG_BROWSABLE = 1 << 0; /** * Flag: Indicates that the item is playable. * <p> * The id of this item may be passed to * {@link MediaController.TransportControls#playFromMediaId(String, Bundle)} * to start playing it. * </p> */ public static final int FLAG_PLAYABLE = 1 << 1; /** * Create a new MediaItem for use in browsing media. * @param description The description of the media, which must include a * media id. * @param flags The flags for this item. */ public MediaItem(@NonNull MediaDescription description, @Flags int flags) { if (description == null) { throw new IllegalArgumentException("description cannot be null"); } if (TextUtils.isEmpty(description.getMediaId())) { throw new IllegalArgumentException("description must have a non-empty media id"); } mFlags = flags; mDescription = description; } /** * Private constructor. */ private MediaItem(Parcel in) { mFlags = in.readInt(); mDescription = MediaDescription.CREATOR.createFromParcel(in); } @Override public int describeContents() { return 0; } @Override public void writeToParcel(Parcel out, int flags) { out.writeInt(mFlags); mDescription.writeToParcel(out, flags); } @Override public String toString() { final StringBuilder sb = new StringBuilder("MediaItem{"); sb.append("mFlags=").append(mFlags); sb.append(", mDescription=").append(mDescription); sb.append('}'); return sb.toString(); } public static final Parcelable.Creator<MediaItem> CREATOR = new Parcelable.Creator<MediaItem>() { @Override public MediaItem createFromParcel(Parcel in) { return new MediaItem(in); } @Override public MediaItem[] newArray(int size) { return new MediaItem[size]; } }; /** * Gets the flags of the item. */ public @Flags int getFlags() { return mFlags; } /** * Returns whether this item is browsable. * @see #FLAG_BROWSABLE */ public boolean isBrowsable() { return (mFlags & FLAG_BROWSABLE) != 0; } /** * Returns whether this item is playable. * @see #FLAG_PLAYABLE */ public boolean isPlayable() { return (mFlags & FLAG_PLAYABLE) != 0; } /** * Returns the description of the media. */ public @NonNull MediaDescription getDescription() { return mDescription; } /** * Returns the media id in the {@link MediaDescription} for this item. * @see android.media.MediaMetadata#METADATA_KEY_MEDIA_ID */ public @Nullable String getMediaId() { return mDescription.getMediaId(); } } /** * Callbacks for connection related events. */ public static class ConnectionCallback { /** * Invoked after {@link MediaBrowser#connect()} when the request has successfully completed. */ public void onConnected() { } /** * Invoked when the client is disconnected from the media browser. */ public void onConnectionSuspended() { } /** * Invoked when the connection to the media browser failed. */ public void onConnectionFailed() { } } /** * Callbacks for subscription related events. */ public static abstract class SubscriptionCallback { Binder mToken; public SubscriptionCallback() { mToken = new Binder(); } /** * Called when the list of children is loaded or updated. * * @param parentId The media id of the parent media item. * @param children The children which were loaded. */ public void onChildrenLoaded(@NonNull String parentId, @NonNull List<MediaItem> children) { } /** * Called when the list of children is loaded or updated. * * @param parentId The media id of the parent media item. * @param children The children which were loaded. * @param options The bundle of service-specific arguments sent to the media * browser service. The contents of this bundle may affect the * information returned when browsing. */ public void onChildrenLoaded(@NonNull String parentId, @NonNull List<MediaItem> children, @NonNull Bundle options) { } /** * Called when the id doesn't exist or other errors in subscribing. * <p> * If this is called, the subscription remains until {@link MediaBrowser#unsubscribe} * called, because some errors may heal themselves. * </p> * * @param parentId The media id of the parent media item whose children could * not be loaded. */ public void onError(@NonNull String parentId) { } /** * Called when the id doesn't exist or other errors in subscribing. * <p> * If this is called, the subscription remains until {@link MediaBrowser#unsubscribe} * called, because some errors may heal themselves. * </p> * * @param parentId The media id of the parent media item whose children could * not be loaded. * @param options The bundle of service-specific arguments sent to the media * browser service. */ public void onError(@NonNull String parentId, @NonNull Bundle options) { } } /** * Callback for receiving the result of {@link #getItem}. */ public static abstract class ItemCallback { /** * Called when the item has been returned by the connected service. * * @param item The item that was returned or null if it doesn't exist. */ public void onItemLoaded(MediaItem item) { } /** * Called there was an error retrieving it or the connected service doesn't support * {@link #getItem}. * * @param mediaId The media id of the media item which could not be loaded. */ public void onError(@NonNull String mediaId) { } } /** * ServiceConnection to the other app. */ private class MediaServiceConnection implements ServiceConnection { @Override public void onServiceConnected(final ComponentName name, final IBinder binder) { postOrRun(new Runnable() { @Override public void run() { if (DBG) { Log.d(TAG, "MediaServiceConnection.onServiceConnected name=" + name + " binder=" + binder); dump(); } // Make sure we are still the current connection, and that they haven't called // disconnect(). if (!isCurrent("onServiceConnected")) { return; } // Save their binder mServiceBinder = IMediaBrowserService.Stub.asInterface(binder); // We make a new mServiceCallbacks each time we connect so that we can drop // responses from previous connections. mServiceCallbacks = getNewServiceCallbacks(); mState = CONNECT_STATE_CONNECTING; // Call connect, which is async. When we get a response from that we will // say that we're connected. try { if (DBG) { Log.d(TAG, "ServiceCallbacks.onConnect..."); dump(); } mServiceBinder.connect(mContext.getPackageName(), mRootHints, mServiceCallbacks); } catch (RemoteException ex) { // Connect failed, which isn't good. But the auto-reconnect on the service // will take over and we will come back. We will also get the // onServiceDisconnected, which has all the cleanup code. So let that do // it. Log.w(TAG, "RemoteException during connect for " + mServiceComponent); if (DBG) { Log.d(TAG, "ServiceCallbacks.onConnect..."); dump(); } } } }); } @Override public void onServiceDisconnected(final ComponentName name) { postOrRun(new Runnable() { @Override public void run() { if (DBG) { Log.d(TAG, "MediaServiceConnection.onServiceDisconnected name=" + name + " this=" + this + " mServiceConnection=" + mServiceConnection); dump(); } // Make sure we are still the current connection, and that they haven't called // disconnect(). if (!isCurrent("onServiceDisconnected")) { return; } // Clear out what we set in onServiceConnected mServiceBinder = null; mServiceCallbacks = null; // And tell the app that it's suspended. mState = CONNECT_STATE_SUSPENDED; mCallback.onConnectionSuspended(); } }); } private void postOrRun(Runnable r) { if (Thread.currentThread() == mHandler.getLooper().getThread()) { r.run(); } else { mHandler.post(r); } } /** * Return true if this is the current ServiceConnection. Also logs if it's not. */ private boolean isCurrent(String funcName) { if (mServiceConnection != this || mState == CONNECT_STATE_DISCONNECTING || mState == CONNECT_STATE_DISCONNECTED) { if (mState != CONNECT_STATE_DISCONNECTING && mState != CONNECT_STATE_DISCONNECTED) { // Check mState, because otherwise this log is noisy. Log.i(TAG, funcName + " for " + mServiceComponent + " with mServiceConnection=" + mServiceConnection + " this=" + this); } return false; } return true; } } /** * Callbacks from the service. */ private static class ServiceCallbacks extends IMediaBrowserServiceCallbacks.Stub { private WeakReference<MediaBrowser> mMediaBrowser; public ServiceCallbacks(MediaBrowser mediaBrowser) { mMediaBrowser = new WeakReference<MediaBrowser>(mediaBrowser); } /** * The other side has acknowledged our connection. The parameters to this function * are the initial data as requested. */ @Override public void onConnect(String root, MediaSession.Token session, final Bundle extras) { MediaBrowser mediaBrowser = mMediaBrowser.get(); if (mediaBrowser != null) { mediaBrowser.onServiceConnected(this, root, session, extras); } } /** * The other side does not like us. Tell the app via onConnectionFailed. */ @Override public void onConnectFailed() { MediaBrowser mediaBrowser = mMediaBrowser.get(); if (mediaBrowser != null) { mediaBrowser.onConnectionFailed(this); } } @Override public void onLoadChildren(String parentId, ParceledListSlice list) { onLoadChildrenWithOptions(parentId, list, null); } @Override public void onLoadChildrenWithOptions(String parentId, ParceledListSlice list, final Bundle options) { MediaBrowser mediaBrowser = mMediaBrowser.get(); if (mediaBrowser != null) { mediaBrowser.onLoadChildren(this, parentId, list, options); } } } private static class Subscription { private final List<SubscriptionCallback> mCallbacks; private final List<Bundle> mOptionsList; public Subscription() { mCallbacks = new ArrayList<>(); mOptionsList = new ArrayList<>(); } public boolean isEmpty() { return mCallbacks.isEmpty(); } public List<Bundle> getOptionsList() { return mOptionsList; } public List<SubscriptionCallback> getCallbacks() { return mCallbacks; } public SubscriptionCallback getCallback(Context context, Bundle options) { if (options != null) { options.setClassLoader(context.getClassLoader()); } for (int i = 0; i < mOptionsList.size(); ++i) { if (MediaBrowserUtils.areSameOptions(mOptionsList.get(i), options)) { return mCallbacks.get(i); } } return null; } public void putCallback(Context context, Bundle options, SubscriptionCallback callback) { if (options != null) { options.setClassLoader(context.getClassLoader()); } for (int i = 0; i < mOptionsList.size(); ++i) { if (MediaBrowserUtils.areSameOptions(mOptionsList.get(i), options)) { mCallbacks.set(i, callback); return; } } mCallbacks.add(callback); mOptionsList.add(options); } } }