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 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); } }