com.allthatseries.RNAudioPlayer.Playback.java Source code

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/*
 * 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 com.allthatseries.RNAudioPlayer;

import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.media.AudioManager;
import android.media.MediaPlayer;
import android.net.Uri;
import android.net.wifi.WifiManager;
import android.os.Bundle;
import android.os.Handler;
import android.os.PowerManager;
import android.support.v4.content.LocalBroadcastManager;
import android.support.v4.media.MediaMetadataCompat;
import android.support.v4.media.session.PlaybackStateCompat;
import android.util.Log;

import java.io.IOException;

import static android.media.MediaPlayer.OnCompletionListener;
import static android.media.MediaPlayer.OnErrorListener;
import static android.media.MediaPlayer.OnPreparedListener;
import static android.media.MediaPlayer.OnSeekCompleteListener;

/**
 * A class that implements local media playback using {@link MediaPlayer}
 */
public class Playback implements AudioManager.OnAudioFocusChangeListener, OnCompletionListener, OnErrorListener,
        OnPreparedListener, OnSeekCompleteListener {

    private static final String TAG = Playback.class.getSimpleName();

    // The volume we set the media player to when we lose audio focus, but are
    // allowed to reduce the volume instead of stopping playback.
    public static final float VOLUME_DUCK = 0.2f;
    // The volume we set the media player when we have audio focus.
    public static final float VOLUME_NORMAL = 1.0f;

    // we don't have audio focus, and can't duck (play at a low volume)
    private static final int AUDIO_NO_FOCUS_NO_DUCK = 0;
    // we don't have focus, but can duck (play at a low volume)
    private static final int AUDIO_NO_FOCUS_CAN_DUCK = 1;
    // we have full audio focus
    private static final int AUDIO_FOCUSED = 2;

    private final Context mContext;
    private final WifiManager.WifiLock mWifiLock;
    private int mState;
    private boolean mPlayOnFocusGain;
    private Callback mCallback;
    private volatile boolean mAudioNoisyReceiverRegistered;
    private volatile int mCurrentPosition;

    // Type of audio focus we have:
    private int mAudioFocus = AUDIO_NO_FOCUS_NO_DUCK;
    private final AudioManager mAudioManager;
    private MediaPlayer mMediaPlayer;

    private final IntentFilter mAudioNoisyIntentFilter = new IntentFilter(AudioManager.ACTION_AUDIO_BECOMING_NOISY);
    private Handler mHandler = new Handler();

    private final BroadcastReceiver mAudioNoisyReceiver = new BroadcastReceiver() {
        @Override
        public void onReceive(Context context, Intent intent) {
            if (AudioManager.ACTION_AUDIO_BECOMING_NOISY.equals(intent.getAction())) {
                if (isPlaying()) {
                    Intent i = new Intent(context, AudioPlayerService.class);
                    i.setAction(AudioPlayerService.ACTION_CMD);
                    i.putExtra(AudioPlayerService.CMD_NAME, AudioPlayerService.CMD_PAUSE);
                    mContext.startService(i);
                }
            }
        }
    };

    public Playback(Context context) {
        this.mContext = context;
        this.mAudioManager = (AudioManager) context.getSystemService(Context.AUDIO_SERVICE);
        // Create the Wifi lock (this does not acquire the lock, this just creates it)
        this.mWifiLock = ((WifiManager) context.getSystemService(Context.WIFI_SERVICE))
                .createWifiLock(WifiManager.WIFI_MODE_FULL, "playback_lock");
        this.mState = PlaybackStateCompat.STATE_NONE;
    }

    public void setState(int state) {
        this.mState = state;
    }

    public int getState() {
        return mState;
    }

    public boolean isPlaying() {
        return mPlayOnFocusGain || (mMediaPlayer != null && mMediaPlayer.isPlaying());
    }

    public int getCurrentPosition() {
        return mMediaPlayer != null ? mMediaPlayer.getCurrentPosition() : mCurrentPosition;
    }

    public void setCurrentPosition(int pos) {
        this.mCurrentPosition = pos;
    }

    public int getDuration() {
        return mMediaPlayer != null ? mMediaPlayer.getDuration() : 0;
    }

    public void playFromUri(Uri uri, Bundle bundle) {
        mPlayOnFocusGain = true;
        tryToGetAudioFocus();
        registerAudioNoisyReceiver();

        mState = PlaybackStateCompat.STATE_STOPPED;
        relaxResources(true);

        try {
            createMediaPlayerIfNeeded();

            mState = PlaybackStateCompat.STATE_BUFFERING;
            mCurrentPosition = 0;

            mMediaPlayer.setAudioStreamType(AudioManager.STREAM_MUSIC);
            mMediaPlayer.setDataSource(uri.toString());

            // Starts preparing the media player in the background. When
            // it's done, it will call our OnPreparedListener (that is,
            // the onPrepared() method on this class, since we set the
            // listener to 'this'). Until the media player is prepared,
            // we *cannot* call start() on it!
            mMediaPlayer.prepareAsync();

            // If we are streaming from the internet, we want to hold a
            // Wifi lock, which prevents the Wifi radio from going to
            // sleep while the song is playing.
            mWifiLock.acquire();

            if (mCallback != null) {
                mCallback.onPlaybackStateChanged(mState);

                MediaMetadataCompat.Builder metaBuilder = new MediaMetadataCompat.Builder();
                metaBuilder.putString(MediaMetadataCompat.METADATA_KEY_ARTIST,
                        bundle.getString(MediaMetadataCompat.METADATA_KEY_ARTIST));
                metaBuilder.putString(MediaMetadataCompat.METADATA_KEY_TITLE,
                        bundle.getString(MediaMetadataCompat.METADATA_KEY_TITLE));
                metaBuilder.putString(MediaMetadataCompat.METADATA_KEY_ALBUM_ART_URI,
                        bundle.getString(MediaMetadataCompat.METADATA_KEY_ALBUM_ART_URI));
                mCallback.onMediaMetadataChanged(metaBuilder.build());
            }

        } catch (IOException ex) {
            Log.e(TAG, ex + "Exception playing song");
            if (mCallback != null) {
                mCallback.onError(ex.getMessage());
            }
        }
    }

    public void resume() {
        mPlayOnFocusGain = true;
        tryToGetAudioFocus();
        registerAudioNoisyReceiver();

        configMediaPlayerState();
    }

    public void pause() {
        if (mState == PlaybackStateCompat.STATE_PLAYING) {
            // Pause media player and cancel the 'foreground service' state.
            if (mMediaPlayer != null && mMediaPlayer.isPlaying()) {
                mMediaPlayer.pause();
                mCurrentPosition = mMediaPlayer.getCurrentPosition();
            }
            // while paused, retain the MediaPlayer but give up audio focus
            relaxResources(false);
        }
        mState = PlaybackStateCompat.STATE_PAUSED;
        if (mCallback != null) {
            mCallback.onPlaybackStateChanged(mState);
        }

        unregisterAudioNoisyReceiver();
    }

    public void seekTo(int position) {
        if (mMediaPlayer == null) {
            // If we do not have a current media player, simply update the current position
            mCurrentPosition = position;
        } else {
            if (mMediaPlayer.isPlaying()) {
                mState = PlaybackStateCompat.STATE_BUFFERING;
            }
            registerAudioNoisyReceiver();
            mMediaPlayer.seekTo(position);
            if (mCallback != null) {
                mCallback.onPlaybackStateChanged(mState);
            }
        }
    }

    public void stop() {
        mState = PlaybackStateCompat.STATE_STOPPED;
        if (mCallback != null) {
            mCallback.onPlaybackStateChanged(mState);
        }
        mCurrentPosition = 0;
        // Give up Audio focus
        giveUpAudioFocus();
        unregisterAudioNoisyReceiver();
        // Relax all resources
        relaxResources(true);
    }

    public void setCallback(Callback callback) {
        this.mCallback = callback;
    }

    /**
     * Try to get the system audio focus.
     */
    private void tryToGetAudioFocus() {
        int result = mAudioManager.requestAudioFocus(this, AudioManager.STREAM_MUSIC, AudioManager.AUDIOFOCUS_GAIN);
        if (result == AudioManager.AUDIOFOCUS_REQUEST_GRANTED) {
            mAudioFocus = AUDIO_FOCUSED;
        } else {
            mAudioFocus = AUDIO_NO_FOCUS_NO_DUCK;
        }
    }

    /**
     * Give up the audio focus.
     */
    private void giveUpAudioFocus() {
        if (mAudioManager.abandonAudioFocus(this) == AudioManager.AUDIOFOCUS_REQUEST_GRANTED) {
            mAudioFocus = AUDIO_NO_FOCUS_NO_DUCK;
        }
    }

    /**
     * Reconfigures MediaPlayer according to audio focus settings and
     * starts/restarts it. This method starts/restarts the MediaPlayer
     * respecting the current audio focus state. So if we have focus, it will
     * play normally; if we don't have focus, it will either leave the
     * MediaPlayer paused or set it to a low volume, depending on what is
     * allowed by the current focus settings. This method assumes mPlayer !=
     * null, so if you are calling it, you have to do so from a context where
     * you are sure this is the case.
     */
    private void configMediaPlayerState() {
        if (mAudioFocus == AUDIO_NO_FOCUS_NO_DUCK) {
            // If we don't have audio focus and can't duck, we have to pause,
            if (mState == PlaybackStateCompat.STATE_PLAYING) {
                pause();
            }
        } else { // we have audio focus:
            registerAudioNoisyReceiver();
            if (mAudioFocus == AUDIO_NO_FOCUS_CAN_DUCK) {
                mMediaPlayer.setVolume(VOLUME_DUCK, VOLUME_DUCK); // we'll be relatively quiet
            } else {
                if (mMediaPlayer != null) {
                    mMediaPlayer.setVolume(VOLUME_NORMAL, VOLUME_NORMAL); // we can be loud again
                } // else do something for remote client.
            }
            // If we were playing when we lost focus, we need to resume playing.
            if (mPlayOnFocusGain) {
                if (mMediaPlayer != null && !mMediaPlayer.isPlaying()) {
                    if (mCurrentPosition == mMediaPlayer.getCurrentPosition()) {
                        mMediaPlayer.start();
                        mState = PlaybackStateCompat.STATE_PLAYING;
                    } else {
                        mMediaPlayer.seekTo(mCurrentPosition);
                        mState = PlaybackStateCompat.STATE_BUFFERING;
                    }
                }
                mPlayOnFocusGain = false;
            }
        }
        if (mCallback != null) {
            mCallback.onPlaybackStateChanged(mState);
        }
    }

    /**
     * Called by AudioManager on audio focus changes.
     * Implementation of {@link AudioManager.OnAudioFocusChangeListener}
     */
    @Override
    public void onAudioFocusChange(int focusChange) {
        if (focusChange == AudioManager.AUDIOFOCUS_GAIN) {
            // We have gained focus:
            mAudioFocus = AUDIO_FOCUSED;

        } else if (focusChange == AudioManager.AUDIOFOCUS_LOSS
                || focusChange == AudioManager.AUDIOFOCUS_LOSS_TRANSIENT
                || focusChange == AudioManager.AUDIOFOCUS_LOSS_TRANSIENT_CAN_DUCK) {
            // We have lost focus. If we can duck (low playback volume), we can keep playing.
            // Otherwise, we need to pause the playback.
            boolean canDuck = focusChange == AudioManager.AUDIOFOCUS_LOSS_TRANSIENT_CAN_DUCK;
            mAudioFocus = canDuck ? AUDIO_NO_FOCUS_CAN_DUCK : AUDIO_NO_FOCUS_NO_DUCK;

            // If we are playing, we need to reset media player by calling configMediaPlayerState
            // with mAudioFocus properly set.
            if (mState == PlaybackStateCompat.STATE_PLAYING && !canDuck) {
                // If we don't have audio focus and can't duck, we save the information that
                // we were playing, so that we can resume playback once we get the focus back.
                mPlayOnFocusGain = true;
            }
        } else {
            Log.e(TAG, "onAudioFocusChange: Ignoring unsupported focusChange: " + focusChange);
        }
        configMediaPlayerState();
    }

    /**
     * Called when MediaPlayer has completed a seek
     *
     * @see OnSeekCompleteListener
     */
    @Override
    public void onSeekComplete(MediaPlayer mp) {
        mCurrentPosition = mp.getCurrentPosition();
        if (mState == PlaybackStateCompat.STATE_BUFFERING) {
            registerAudioNoisyReceiver();
            mMediaPlayer.start();
            mState = PlaybackStateCompat.STATE_PLAYING;
        }
        if (mCallback != null) {
            mCallback.onPlaybackStateChanged(mState);
        }
    }

    /**
     * Called when media player is done playing current song.
     *
     * @see OnCompletionListener
     */
    @Override
    public void onCompletion(MediaPlayer player) {
        if (mCallback != null) {
            mState = PlaybackStateCompat.STATE_PAUSED;
            mCallback.onCompletion();
        }
    }

    /**
     * Called when media player is done preparing.
     *
     * @see OnPreparedListener
     */
    @Override
    public void onPrepared(MediaPlayer player) {
        // The media player is done preparing. That means we can start playing if we have audio focus.
        configMediaPlayerState();
    }

    /**
     * Called when there's an error playing media. When this happens, the media
     * player goes to the Error state. We warn the user about the error and
     * reset the media player.
     *
     * @see OnErrorListener
     */
    @Override
    public boolean onError(MediaPlayer mp, int what, int extra) {
        if (mCallback != null) {
            mCallback.onError("MediaPlayer error " + what + " (" + extra + ")");
        }

        return true; // true indicates we handled the error
    }

    /**
     * Makes sure the media player exists and has been reset. This will create
     * the media player if needed, or reset the existing media player if one
     * already exists.
     */
    private void createMediaPlayerIfNeeded() {
        if (mMediaPlayer == null) {
            mMediaPlayer = new MediaPlayer();

            // Make sure the media player will acquire a wake-lock while
            // playing. If we don't do that, the CPU might go to sleep while the
            // song is playing, causing playback to stop.
            mMediaPlayer.setWakeMode(mContext.getApplicationContext(), PowerManager.PARTIAL_WAKE_LOCK);

            // we want the media player to notify us when it's ready preparing,
            // and when it's done playing:
            mMediaPlayer.setOnPreparedListener(this);
            mMediaPlayer.setOnCompletionListener(this);
            mMediaPlayer.setOnErrorListener(this);
            mMediaPlayer.setOnSeekCompleteListener(this);

            new Thread(new Runnable() {
                @Override
                public void run() {
                    while (mMediaPlayer != null) {
                        try {
                            Thread.sleep(500);
                            mHandler.post(new Runnable() {
                                @Override
                                public void run() {
                                    if (mMediaPlayer != null && mMediaPlayer.isPlaying()) {
                                        Intent intent = new Intent("update-position-event");
                                        intent.putExtra("currentPosition", mMediaPlayer.getCurrentPosition());
                                        LocalBroadcastManager.getInstance(mContext).sendBroadcast(intent);
                                    }
                                }
                            });

                        } catch (Exception e) {
                            e.printStackTrace();
                        }
                    }
                }
            }).start();

        } else {
            mMediaPlayer.reset();
        }
    }

    /**
     * Releases resources used by the service for playback. This includes the
     * "foreground service" status, the wake locks and possibly the MediaPlayer.
     *
     * @param releaseMediaPlayer Indicates whether the Media Player should also
     *            be released or not
     */
    private void relaxResources(boolean releaseMediaPlayer) {
        // stop and release the Media Player, if it's available
        if (releaseMediaPlayer && mMediaPlayer != null) {
            mMediaPlayer.reset();
            mMediaPlayer.release();
            mMediaPlayer = null;
        }

        // we can also release the Wifi lock, if we're holding it
        if (mWifiLock.isHeld()) {
            mWifiLock.release();
        }
    }

    private void registerAudioNoisyReceiver() {
        if (!mAudioNoisyReceiverRegistered) {
            mContext.registerReceiver(mAudioNoisyReceiver, mAudioNoisyIntentFilter);
            mAudioNoisyReceiverRegistered = true;
        }
    }

    private void unregisterAudioNoisyReceiver() {
        if (mAudioNoisyReceiverRegistered) {
            mContext.unregisterReceiver(mAudioNoisyReceiver);
            mAudioNoisyReceiverRegistered = false;
        }
    }

    public interface Callback {
        /**
         * On current music completed.
         */
        void onCompletion();

        /**
         * on PlaybackState changed
         * Implementations can use this callback to update
         * playback state on the media sessions.
         */
        void onPlaybackStateChanged(int state);

        /**
         * on MediaMetadata changed
         * @param metadata
         */
        void onMediaMetadataChanged(MediaMetadataCompat metadata);

        /**
         * @param error to be added to the PlaybackState
         */
        void onError(String error);
    }
}