Make MediaSession and MediaController constructors public

This makes the MediaSession/Controller constructors public and registers
with the system behind the scenes.

This also adds a bit about needing to call setActive(true) to start receiving
commands in MediaSession's docs.

Change-Id: If882d229b54c36bf0831aca0255052dda667a2bc

4 files changed, 72 insertions, 58 deletions

diff --git a/media/java/android/media/session/MediaController.java b/media/java/android/media/session/MediaController.java
index cc8b31a..ed45a08 100644
--- a/media/java/android/media/session/MediaController.java
+++ b/media/java/android/media/session/MediaController.java
@@ -66,28 +66,27 @@ public final class MediaController {
 
     private final TransportControls mTransportControls;
 
-    private MediaController(ISessionController sessionBinder) {
-        mSessionBinder = sessionBinder;
-        mTransportControls = new TransportControls();
-    }
-
     /**
+     * Call for creating a MediaController directly from a binder. Should only
+     * be used by framework code.
+     *
      * @hide
      */
-    public static MediaController fromBinder(ISessionController sessionBinder) {
-        return new MediaController(sessionBinder);
+    public MediaController(ISessionController sessionBinder) {
+        if (sessionBinder == null) {
+            throw new IllegalArgumentException("Session token cannot be null");
+        }
+        mSessionBinder = sessionBinder;
+        mTransportControls = new TransportControls();
     }
 
     /**
-     * Get a new media controller from a session token which may have
-     * been obtained from another process.  If successful the controller returned
-     * will be connected to the session that generated the token.
+     * Create a new MediaController from a session's token.
      *
-     * @param token The session token to control.
-     * @return A controller for the session or null if inaccessible.
+     * @param token The token for the session.
      */
-    public static MediaController fromToken(@NonNull MediaSession.Token token) {
-        return fromBinder(token.getBinder());
+    public MediaController(@NonNull MediaSession.Token token) {
+        this(token.getBinder());
     }
 
     /**
diff --git a/media/java/android/media/session/MediaSession.java b/media/java/android/media/session/MediaSession.java
index 34997bd..cdb61e1 100644
--- a/media/java/android/media/session/MediaSession.java
+++ b/media/java/android/media/session/MediaSession.java
@@ -20,6 +20,7 @@ import android.annotation.NonNull;
 import android.annotation.Nullable;
 import android.app.PendingIntent;
 import android.content.ComponentName;
+import android.content.Context;
 import android.content.Intent;
 import android.media.AudioManager;
 import android.media.MediaMetadata;
@@ -37,10 +38,13 @@ import android.os.Parcel;
 import android.os.Parcelable;
 import android.os.RemoteException;
 import android.os.ResultReceiver;
+import android.os.UserHandle;
 import android.text.TextUtils;
 import android.util.ArrayMap;
 import android.util.Log;
 
+import com.android.internal.telephony.DctConstants.Activity;
+
 import java.lang.ref.WeakReference;
 import java.util.ArrayList;
 import java.util.List;
@@ -59,8 +63,9 @@ import java.util.List;
  * create a {@link MediaController} to interact with the session.
  * <p>
  * To receive commands, media keys, and other events a {@link Callback} must be
- * set with {@link #addCallback(Callback)}. To receive transport control
- * commands a {@link TransportControlsCallback} must be set with
+ * set with {@link #addCallback(Callback)} and {@link #setActive(boolean)
+ * setActive(true)} must be called. To receive transport control commands a
+ * {@link TransportControlsCallback} must be set with
  * {@link #addTransportControlsCallback}.
  * <p>
  * When an app is finished performing playback it must call {@link #release()}
@@ -119,18 +124,45 @@ public final class MediaSession {
     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(ISession binder, CallbackStub cbStub) {
-        mBinder = binder;
-        mCbStub = cbStub;
-        ISessionController controllerBinder = null;
+    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");
+        }
+        mCbStub = new CallbackStub();
+        MediaSessionManager manager = (MediaSessionManager) context
+                .getSystemService(Context.MEDIA_SESSION_SERVICE);
         try {
-            controllerBinder = mBinder.getController();
+            mBinder = manager.createSession(mCbStub, tag, userId);
+            mSessionToken = new Token(mBinder.getController());
         } catch (RemoteException e) {
-            throw new RuntimeException("Dead object in MediaSessionController constructor: ", e);
+            throw new RuntimeException("Remote error creating session.", e);
         }
-        mSessionToken = new Token(controllerBinder);
     }
 
     /**
diff --git a/media/java/android/media/session/MediaSessionLegacyHelper.java b/media/java/android/media/session/MediaSessionLegacyHelper.java
index 11f7720..5af793f 100644
--- a/media/java/android/media/session/MediaSessionLegacyHelper.java
+++ b/media/java/android/media/session/MediaSessionLegacyHelper.java
@@ -28,6 +28,7 @@ import android.media.MediaMetadataRetriever;
 import android.os.Bundle;
 import android.os.Handler;
 import android.os.Looper;
+import android.os.RemoteException;
 import android.util.ArrayMap;
 import android.util.Log;
 import android.view.KeyEvent;
@@ -46,6 +47,7 @@ public class MediaSessionLegacyHelper {
     private static final Object sLock = new Object();
     private static MediaSessionLegacyHelper sInstance;
 
+    private Context mContext;
     private MediaSessionManager mSessionManager;
     private Handler mHandler = new Handler(Looper.getMainLooper());
     // The legacy APIs use PendingIntents to register/unregister media button
@@ -54,6 +56,7 @@ public class MediaSessionLegacyHelper {
             = new ArrayMap<PendingIntent, SessionHolder>();
 
     private MediaSessionLegacyHelper(Context context) {
+        mContext = context;
         mSessionManager = (MediaSessionManager) context
                 .getSystemService(Context.MEDIA_SESSION_SERVICE);
     }
@@ -225,6 +228,9 @@ public class MediaSessionLegacyHelper {
             return;
         }
         SessionHolder holder = getHolder(pi, true);
+        if (holder == null) {
+            return;
+        }
         if (holder.mRccListener != null) {
             if (holder.mRccListener == listener) {
                 if (DEBUG) {
@@ -270,6 +276,9 @@ public class MediaSessionLegacyHelper {
             return;
         }
         SessionHolder holder = getHolder(pi, true);
+        if (holder == null) {
+            return;
+        }
         if (holder.mMediaButtonListener != null) {
             // Already have this listener registered, but update it anyway as
             // the extras may have changed.
@@ -316,7 +325,8 @@ public class MediaSessionLegacyHelper {
     private SessionHolder getHolder(PendingIntent pi, boolean createIfMissing) {
         SessionHolder holder = mSessions.get(pi);
         if (holder == null && createIfMissing) {
-            MediaSession session = mSessionManager.createSession(TAG);
+            MediaSession session;
+            session = new MediaSession(mContext, TAG);
             session.setActive(true);
             holder = new SessionHolder(session, pi);
             mSessions.put(pi, holder);
diff --git a/media/java/android/media/session/MediaSessionManager.java b/media/java/android/media/session/MediaSessionManager.java
index c477406..12013b6 100644
--- a/media/java/android/media/session/MediaSessionManager.java
+++ b/media/java/android/media/session/MediaSessionManager.java
@@ -64,42 +64,15 @@ public final class MediaSessionManager {
     }
 
     /**
-     * Creates a new session.
+     * Create a new session in the system and get the binder for it.
      *
      * @param tag A short name for debugging purposes.
-     * @return A {@link MediaSession} for the new session.
-     */
-    public @NonNull MediaSession createSession(@NonNull String tag) {
-        return createSessionAsUser(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 tag A short name for debugging purposes.
-     * @param userId The user id to create the session as.
-     * @return A {@link MediaSession} for the new session.
+     * @return The binder object from the system
      * @hide
      */
-    public @NonNull MediaSession createSessionAsUser(@NonNull String tag, int userId) {
-        if (TextUtils.isEmpty(tag)) {
-            throw new IllegalArgumentException("tag must not be null or empty");
-        }
-
-        try {
-            MediaSession.CallbackStub cbStub = new MediaSession.CallbackStub();
-            MediaSession session = new MediaSession(mService
-                    .createSession(mContext.getPackageName(), cbStub, tag, userId), cbStub);
-            cbStub.setMediaSession(session);
-
-            return session;
-        } catch (RemoteException e) {
-            Log.e(TAG, "Failed to create session: ", e);
-            return null;
-        }
+    public @NonNull ISession createSession(@NonNull MediaSession.CallbackStub cbStub,
+            @NonNull String tag, int userId) throws RemoteException {
+        return mService.createSession(mContext.getPackageName(), cbStub, tag, userId);
     }
 
     /**
@@ -142,7 +115,7 @@ public final class MediaSessionManager {
             List<IBinder> binders = mService.getSessions(notificationListener, userId);
             int size = binders.size();
             for (int i = 0; i < size; i++) {
-                MediaController controller = MediaController.fromBinder(ISessionController.Stub
+                MediaController controller = new MediaController(ISessionController.Stub
                         .asInterface(binders.get(i)));
                 controllers.add(controller);
             }
@@ -295,7 +268,7 @@ public final class MediaSessionManager {
                 ArrayList<MediaController> controllers = new ArrayList<MediaController>();
                 int size = tokens.size();
                 for (int i = 0; i < size; i++) {
-                    controllers.add(MediaController.fromToken(tokens.get(i)));
+                    controllers.add(new MediaController(tokens.get(i)));
                 }
                 SessionListener.this.onActiveSessionsChanged(controllers);
             }