Android/app/src/main/java/com/moiseum/wolnelektury/view/player/service/MediaPlayerAdapter.java

   1 /*
   2  * Copyright 2017 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
  17 package com.moiseum.wolnelektury.view.player.service;
  18
  19 import android.content.Context;
  20 import android.content.res.AssetFileDescriptor;
  21 import android.media.MediaPlayer;
  22 import android.os.Bundle;
  23 import android.os.Handler;
  24 import android.os.SystemClock;
  25 import android.support.v4.media.MediaMetadataCompat;
  26 import android.support.v4.media.session.PlaybackStateCompat;
  27 import android.util.Log;
  28
  29 import com.moiseum.wolnelektury.connection.downloads.FileCacheUtils;
  30
  31 /**
  32  * Exposes the functionality of the {@link MediaPlayer} and implements the {@link PlayerAdapter}
  33  * so that MainActivity can control music playback.
  34  */
  35 public final class MediaPlayerAdapter extends PlayerAdapter {
  36
  37         private class MediaPlayerException extends Exception {
  38
  39                 private final int what;
  40                 private final int extra;
  41
  42                 public MediaPlayerException(int what, int extra) {
  43                         this.what = what;
  44                         this.extra = extra;
  45                 }
  46
  47                 @Override
  48                 public String getMessage() {
  49                         return "Media player failed with code (" + what + "," + extra + ")";
  50                 }
  51         }
  52
  53         private static final String TAG = MediaPlayerAdapter.class.getSimpleName();
  54         private static final int FIVE_SECONDS = 5000;
  55         private static final int CALLBACK_INTERVAL = 400;
  56
  57     private final Context mContext;
  58     private MediaPlayer mMediaPlayer;
  59     private String mFilename;
  60     private PlaybackInfoListener mPlaybackInfoListener;
  61     private MediaMetadataCompat mCurrentMedia;
  62     private int mState;
  63     private boolean mCurrentMediaPlayedToCompletion;
  64
  65         private Handler handler = new Handler();
  66         private Runnable positionUpdateRunnable = new Runnable() {
  67                 @Override
  68                 public void run() {
  69                         mPlaybackInfoListener.onPlaybackProgress(mMediaPlayer.getCurrentPosition());
  70                         handler.postDelayed(this, CALLBACK_INTERVAL);
  71                 }
  72         };
  73
  74     // Work-around for a MediaPlayer bug related to the behavior of MediaPlayer.seekTo()
  75     // while not playing.
  76     private int mSeekWhileNotPlaying = -1;
  77
  78     MediaPlayerAdapter(Context context, PlaybackInfoListener listener) {
  79         super(context);
  80         mContext = context.getApplicationContext();
  81         mPlaybackInfoListener = listener;
  82     }
  83
  84     /**
  85      * Once the {@link MediaPlayer} is released, it can't be used again, and another one has to be
  86      * created. In the onStop() method of the MainActivity the {@link MediaPlayer} is
  87      * released. Then in the onStart() of the MainActivity a new {@link MediaPlayer}
  88      * object has to be created. That's why this method is private, and called by load(int) and
  89      * not the constructor.
  90      */
  91     private void initializeMediaPlayer() {
  92         if (mMediaPlayer == null) {
  93             mMediaPlayer = new MediaPlayer();
  94             mMediaPlayer.setOnCompletionListener(mediaPlayer -> {
  95                 mPlaybackInfoListener.onPlaybackCompleted();
  96
  97                 // Set the state to "paused" because it most closely matches the state
  98                 // in MediaPlayer with regards to available state transitions compared
  99                 // to "stop".
 100                 // Paused allows: seekTo(), start(), pause(), stop()
 101                 // Stop allows: stop()
 102                 setNewState(PlaybackStateCompat.STATE_PAUSED);
 103             });
 104             mMediaPlayer.setOnErrorListener((mp, what, extra) -> {
 105                     Log.e(TAG, "Media player experienced failure: " + what + ", " + extra);
 106                 setNewState(PlaybackStateCompat.STATE_ERROR);
 107                     return false;
 108             });
 109         }
 110     }
 111
 112     // Implements PlaybackControl.
 113     @Override
 114     public void playFromMedia(MediaMetadataCompat metadata) {
 115         mCurrentMedia = metadata;
 116         final String mediaId = metadata.getDescription().getMediaId();
 117         playFile(AudiobookLibrary.getMusicFilename(mediaId));
 118     }
 119
 120     @Override
 121     public MediaMetadataCompat getCurrentMedia() {
 122         return mCurrentMedia;
 123     }
 124
 125     private void playFile(String filename) {
 126         boolean mediaChanged = (mFilename == null || !filename.equals(mFilename));
 127         if (mCurrentMediaPlayedToCompletion) {
 128             // Last audio file was played to completion, the resourceId hasn't changed, but the
 129             // player was released, so force a reload of the media file for playback.
 130             mediaChanged = true;
 131             mCurrentMediaPlayedToCompletion = false;
 132         }
 133         if (!mediaChanged) {
 134             if (!isPlaying()) {
 135                 play();
 136             }
 137             return;
 138         } else {
 139             release();
 140         }
 141
 142         mFilename = filename;
 143
 144         initializeMediaPlayer();
 145
 146         try {
 147             String cachedFileForUrl = FileCacheUtils.getCachedFileForUrl(mFilename);
 148             mMediaPlayer.setDataSource(cachedFileForUrl);
 149             mMediaPlayer.prepare();
 150             mPlaybackInfoListener.onPlaybackPrepared(mMediaPlayer.getDuration());
 151         } catch (Exception e) {
 152                 Log.e(TAG, "Failed to load file: " + mFilename, e);
 153                 setNewState(PlaybackStateCompat.STATE_ERROR);
 154         }
 155
 156         play();
 157     }
 158
 159     @Override
 160     public void onStop() {
 161         // Regardless of whether or not the MediaPlayer has been created / started, the state must
 162         // be updated, so that MediaNotificationManager can take down the notification.
 163         setNewState(PlaybackStateCompat.STATE_STOPPED);
 164         release();
 165     }
 166
 167     private void release() {
 168         if (mMediaPlayer != null) {
 169                 handler.removeCallbacks(positionUpdateRunnable);
 170             mMediaPlayer.release();
 171             mMediaPlayer = null;
 172         }
 173     }
 174
 175     @Override
 176     public boolean isPlaying() {
 177         return mMediaPlayer != null && mMediaPlayer.isPlaying();
 178     }
 179
 180     @Override
 181     protected void onPlay() {
 182         if (mMediaPlayer != null && !mMediaPlayer.isPlaying()) {
 183             mMediaPlayer.start();
 184                 handler.postDelayed(positionUpdateRunnable, CALLBACK_INTERVAL);
 185             setNewState(PlaybackStateCompat.STATE_PLAYING);
 186         }
 187     }
 188
 189     @Override
 190     protected void onPause() {
 191         if (mMediaPlayer != null && mMediaPlayer.isPlaying()) {
 192             mMediaPlayer.pause();
 193                 handler.removeCallbacks(positionUpdateRunnable);
 194             setNewState(PlaybackStateCompat.STATE_PAUSED);
 195         }
 196     }
 197
 198     // This is the main reducer for the player state machine.
 199     private void setNewState(@PlaybackStateCompat.State int newPlayerState) {
 200         mState = newPlayerState;
 201         if (mState == PlaybackStateCompat.STATE_ERROR) {
 202                 handler.removeCallbacks(positionUpdateRunnable);
 203                 mFilename = null;
 204         }
 205
 206         // Whether playback goes to completion, or whether it is stopped, the
 207         // mCurrentMediaPlayedToCompletion is set to true.
 208         if (mState == PlaybackStateCompat.STATE_STOPPED) {
 209             mCurrentMediaPlayedToCompletion = true;
 210         }
 211
 212         // Work around for MediaPlayer.getCurrentPosition() when it changes while not playing.
 213         final long reportPosition;
 214         if (mSeekWhileNotPlaying >= 0) {
 215             reportPosition = mSeekWhileNotPlaying;
 216
 217             if (mState == PlaybackStateCompat.STATE_PLAYING) {
 218                 mSeekWhileNotPlaying = -1;
 219             }
 220         } else {
 221             reportPosition = mMediaPlayer == null ? 0 : mMediaPlayer.getCurrentPosition();
 222         }
 223
 224         final PlaybackStateCompat.Builder stateBuilder = new PlaybackStateCompat.Builder();
 225         stateBuilder.setActions(getAvailableActions());
 226         stateBuilder.setState(mState,
 227                               reportPosition,
 228                               1.0f,
 229                               SystemClock.elapsedRealtime());
 230         if (mState == PlaybackStateCompat.STATE_PLAYING) {
 231                 Bundle extras = new Bundle();
 232                 extras.putInt(AudiobookService.EXTRA_PLAYBACK_TOTAL, mMediaPlayer.getDuration());
 233                 stateBuilder.setExtras(extras);
 234         }
 235         mPlaybackInfoListener.onPlaybackStateChange(stateBuilder.build());
 236     }
 237
 238     /**
 239      * Set the current capabilities available on this session. Note: If a capability is not
 240      * listed in the bitmask of capabilities then the MediaSession will not handle it. For
 241      * example, if you don't want ACTION_STOP to be handled by the MediaSession, then don't
 242      * included it in the bitmask that's returned.
 243      */
 244     @PlaybackStateCompat.Actions
 245     private long getAvailableActions() {
 246         long actions = PlaybackStateCompat.ACTION_PLAY_FROM_MEDIA_ID
 247                        | PlaybackStateCompat.ACTION_PLAY_FROM_SEARCH
 248                        | PlaybackStateCompat.ACTION_SKIP_TO_NEXT
 249                        | PlaybackStateCompat.ACTION_SKIP_TO_PREVIOUS;
 250         switch (mState) {
 251             case PlaybackStateCompat.STATE_STOPPED:
 252                 actions |= PlaybackStateCompat.ACTION_PLAY
 253                            | PlaybackStateCompat.ACTION_PAUSE;
 254                 break;
 255             case PlaybackStateCompat.STATE_PLAYING:
 256                 actions |= PlaybackStateCompat.ACTION_STOP
 257                            | PlaybackStateCompat.ACTION_PAUSE
 258                            | PlaybackStateCompat.ACTION_SEEK_TO;
 259                 break;
 260             case PlaybackStateCompat.STATE_PAUSED:
 261                 actions |= PlaybackStateCompat.ACTION_PLAY
 262                            | PlaybackStateCompat.ACTION_STOP;
 263                 break;
 264             default:
 265                 actions |= PlaybackStateCompat.ACTION_PLAY
 266                            | PlaybackStateCompat.ACTION_PLAY_PAUSE
 267                            | PlaybackStateCompat.ACTION_STOP
 268                            | PlaybackStateCompat.ACTION_PAUSE;
 269         }
 270         return actions;
 271     }
 272
 273     @Override
 274     public void seekTo(long position) {
 275         if (mMediaPlayer != null) {
 276             if (!mMediaPlayer.isPlaying()) {
 277                 mSeekWhileNotPlaying = (int) position;
 278             }
 279             mMediaPlayer.seekTo((int) position);
 280
 281             // Set the state (to the current state) because the position changed and should
 282             // be reported to clients.
 283             setNewState(mState);
 284         }
 285     }
 286
 287     @Override
 288     public void fastForward() {
 289             if (mMediaPlayer != null) {
 290                 int seekTo = mMediaPlayer.getCurrentPosition() + FIVE_SECONDS;
 291                 int newState = mState;
 292
 293                 if (seekTo > mMediaPlayer.getDuration()) {
 294                         seekTo = mMediaPlayer.getDuration();
 295                         newState = PlaybackStateCompat.STATE_PAUSED;
 296                         mMediaPlayer.pause();
 297                     }
 298
 299                     mMediaPlayer.seekTo(seekTo);
 300                     setNewState(newState);
 301             }
 302     }
 303
 304     @Override
 305     public void rewind() {
 306             if (mMediaPlayer != null) {
 307                     int seekTo = mMediaPlayer.getCurrentPosition() - FIVE_SECONDS;
 308                     int newState = mState;
 309
 310                     if (seekTo < 0) {
 311                             seekTo = 0;
 312                             newState = PlaybackStateCompat.STATE_PAUSED;
 313                             mMediaPlayer.pause();
 314                     }
 315
 316                     mMediaPlayer.seekTo(seekTo);
 317                     setNewState(newState);
 318             }
 319     }
 320
 321     @Override
 322     public void setVolume(float volume) {
 323         if (mMediaPlayer != null) {
 324             mMediaPlayer.setVolume(volume, volume);
 325         }
 326     }
 327 }