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      1 /*
      2  * Copyright (C) 2016 The Android Open Source Project
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *      http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 package com.android.car.cluster.sample;
     17 
     18 import static com.android.car.cluster.sample.DebugUtil.DEBUG;
     19 
     20 import android.content.Context;
     21 import android.media.MediaMetadata;
     22 import android.media.session.MediaController;
     23 import android.media.session.MediaSessionManager;
     24 import android.media.session.MediaSessionManager.OnActiveSessionsChangedListener;
     25 import android.media.session.PlaybackState;
     26 import android.util.Log;
     27 
     28 import java.lang.ref.WeakReference;
     29 import java.util.List;
     30 
     31 /**
     32  * Reports current media status to instrument cluster renderer through {@link MediaStateListener}
     33  */
     34 public class MediaStateMonitor {
     35 
     36     private final static String TAG = DebugUtil.getTag(MediaStateMonitor.class);
     37 
     38     private final Context mContext;
     39     private final MediaListener mMediaListener;
     40     private MediaController mPrimaryMediaController;
     41     private OnActiveSessionsChangedListener mActiveSessionsChangedListener;
     42     private MediaSessionManager mMediaSessionManager;
     43     private MediaStateListener mListener;
     44 
     45     public MediaStateMonitor(Context context, MediaStateListener listener) {
     46         mListener = listener;
     47         mContext = context;
     48         mMediaListener = new MediaListener(this);
     49         mActiveSessionsChangedListener = controllers -> onActiveSessionsChanged(controllers);
     50         mMediaSessionManager = mContext.getSystemService(MediaSessionManager.class);
     51         mMediaSessionManager.addOnActiveSessionsChangedListener(
     52                 mActiveSessionsChangedListener, null);
     53 
     54         onActiveSessionsChanged(mMediaSessionManager.getActiveSessions(null));
     55     }
     56 
     57     private void onActiveSessionsChanged(List<MediaController> controllers) {
     58         if (DEBUG) {
     59             Log.d(TAG, "onActiveSessionsChanged, controllers found:  " + controllers.size());
     60         }
     61         MediaController newPrimaryController = null;
     62         if (!controllers.isEmpty()) {
     63             newPrimaryController = controllers.get(0);
     64             if (mPrimaryMediaController == newPrimaryController) {
     65                 // Primary media controller has not been changed.
     66                 return;
     67             }
     68         }
     69 
     70         releasePrimaryMediaController();
     71 
     72         if (newPrimaryController != null) {
     73             mPrimaryMediaController = newPrimaryController;
     74             mPrimaryMediaController.registerCallback(mMediaListener);
     75             mListener.onMediaAppChanged(
     76                     new MediaAppInfo(mContext, mPrimaryMediaController.getPackageName()));
     77         }
     78         updateRendererMediaStatusIfAvailable();
     79     }
     80 
     81     public void release() {
     82         releasePrimaryMediaController();
     83         if (mActiveSessionsChangedListener != null) {
     84             mMediaSessionManager.removeOnActiveSessionsChangedListener(
     85                     mActiveSessionsChangedListener);
     86             mActiveSessionsChangedListener = null;
     87         }
     88         mMediaSessionManager = null;
     89     }
     90 
     91     private void releasePrimaryMediaController() {
     92         if (mPrimaryMediaController != null) {
     93             mPrimaryMediaController.unregisterCallback(mMediaListener);
     94             mPrimaryMediaController = null;
     95         }
     96     }
     97 
     98     private void updateRendererMediaStatusIfAvailable() {
     99         mListener.onMetadataChanged(
    100                 mPrimaryMediaController == null ? null : mPrimaryMediaController.getMetadata());
    101         mListener.onPlaybackStateChanged(
    102                 mPrimaryMediaController == null
    103                 ? null : mPrimaryMediaController.getPlaybackState());
    104     }
    105 
    106     private void onPlaybackStateChanged(PlaybackState state) {
    107         mListener.onPlaybackStateChanged(state);
    108     }
    109 
    110     private void onMetadataChanged(MediaMetadata metadata) {
    111         mListener.onMetadataChanged(metadata);
    112     }
    113 
    114     public interface MediaStateListener {
    115         void onPlaybackStateChanged(PlaybackState playbackState);
    116         void onMetadataChanged(MediaMetadata metadata);
    117         void onMediaAppChanged(MediaAppInfo mediaAppPackage);
    118     }
    119 
    120     private static class MediaListener extends MediaController.Callback {
    121         private final WeakReference<MediaStateMonitor> mServiceRef;
    122 
    123         MediaListener(MediaStateMonitor service) {
    124             mServiceRef = new WeakReference<>(service);
    125         }
    126 
    127         @Override
    128         public void onPlaybackStateChanged(PlaybackState state) {
    129             MediaStateMonitor service = mServiceRef.get();
    130             if (service != null) {
    131                 service.onPlaybackStateChanged(state);
    132             }
    133         }
    134 
    135         @Override
    136         public void onMetadataChanged(MediaMetadata metadata) {
    137             MediaStateMonitor service = mServiceRef.get();
    138             if (service != null) {
    139                 service.onMetadataChanged(metadata);
    140             }
    141         }
    142     }
    143 }
    144