Android(安卓)使用MediaPlayer播放网络音频

一、前言

MediaPlayer是Android自带的一个多媒体播放类，可以播放音视频流或者本地音视频文件。MediaPlayer方法的调用需要在一定的状态下，下图是一个MediaPlayer对象被支持的播放控制操作驱动的声明周期和状态。其中，椭圆代表MediaPlayer可能驻留的状态，弧线表示驱动MediaPlayer在各个状态之间迁移的播放控制操作。这里有两种类型的弧线。由单箭头开始的弧线代表同步方法调用，而以双箭头开头的弧线代表异步方法调用。图片介绍来源于官方文。

详细介绍可通过Android – 多媒体播放之MediaPlayer基础简介了解更多

二、播放网络音频

现在写一个支持本地缓存的网络音频播放器,并添加了唤醒锁、WiFi锁和音频焦点等功能。

1、自定义MediaPlayer

直接通过MediaPlayer获取播放状态有时不够准确，所以自定义ManagedMediaPlayer继承MediaPlayer，拓展MediaPlayer的功能，控制播放状态

public class ManagedMediaPlayer extends MediaPlayer implements MediaPlayer.OnCompletionListener {    public enum Status {        IDLE, INITIALIZED, STARTED, PAUSED, STOPPED, COMPLETED    }    private Status mState;    private OnCompletionListener mOnCompletionListener;    public ManagedMediaPlayer() {        super();        mState = Status.IDLE;        super.setOnCompletionListener(this);    }    @Override    public void reset() {        super.reset();        mState = Status.IDLE;    }    @Override    public void setDataSource(String path) throws IOException, IllegalArgumentException, SecurityException, IllegalStateException {        super.setDataSource(path);        mState = Status.INITIALIZED;    }    @Override    public void start() {        super.start();        mState = Status.STARTED;    }    @Override    public void setOnCompletionListener(OnCompletionListener listener) {        this.mOnCompletionListener = listener;    }    @Override    public void onCompletion(MediaPlayer mp) {        mState = Status.COMPLETED;        if (mOnCompletionListener != null) {            mOnCompletionListener.onCompletion(mp);        }    }    @Override    public void stop() throws IllegalStateException {        super.stop();        mState = Status.STOPPED;    }    @Override    public void pause() throws IllegalStateException {        super.pause();        mState = Status.PAUSED;    }    public void setState(Status mState) {        this.mState = mState;    }    public Status getState() {        return mState;    }    public boolean isComplete() {        return mState == Status.COMPLETED;    }}

2、唤醒锁、WiFi锁

app在长时间后台运行时，手机有可能会进入休眠，这是CUP和WiFi可能会停止运行，影响到app的正常运行，所以我们需要加入唤醒锁和WiFi锁保证我们在后台长时间播放音频的稳定。
初始化时MediaPlayer时使用唤醒锁并初始化WiFi锁

// 使用唤醒锁mMediaPlayer.setWakeMode(MyApplication.getContext(), PowerManager.PARTIAL_WAKE_LOCK);// 初始化wifi锁WifiManager.WifiLock wifiLock = ((WifiManager) MyApplication.getContext().getApplicationContext().getSystemService(Context.WIFI_SERVICE)).createWifiLock(WifiManager.WIFI_MODE_FULL, "mylock");

在开始播放的时候启用WiFi锁

// 启用wifi锁wifiLock.acquire();

在暂定和释放资源的时候关闭WiFi锁

// 关闭wifi锁if (wifiLock.isHeld()) {    wifiLock.release();}

3、音频焦点

Android系统是一个多任务操作系统，因此同一时刻允许许多任务同时工作。但是这对音频类应用来说是个挑战，因为如果多个音频同时播放的话，很多情况下用户体验会相当的差。当你需要播放音乐或者发送一个通知的时候，你可以去要求获得音频焦点。一旦获得，就可以自由的使用音频输出设备。但是同时它也在时时刻刻的监听着音频焦点的变化。当音频焦点变化时，你需要去合适的处理你的音频输出。
自定义AudioFocusManager实现音频焦点变化监听

public class AudioFocusManager implements AudioManager.OnAudioFocusChangeListener{    private static final String TAG = "AudioFocusManager";    private AudioManager audioManager;    private boolean isPausedByFocusLossTransient;    public AudioFocusManager(Context context) {        audioManager = (AudioManager) context.getSystemService(AUDIO_SERVICE);    }    public boolean requestAudioFocus() {        return audioManager.requestAudioFocus(this, AudioManager.STREAM_MUSIC, AudioManager.AUDIOFOCUS_GAIN)                == AudioManager.AUDIOFOCUS_REQUEST_GRANTED;    }    public void abandonAudioFocus() {        audioManager.abandonAudioFocus(this);    }    @Override    public void onAudioFocusChange(int focusChange) {        switch (focusChange) {            // 重新获得焦点            case AudioManager.AUDIOFOCUS_GAIN:                if (isPausedByFocusLossTransient) {                    // 通话结束，恢复播放                    AudioPlayer.getInstance().resume();                }                // 恢复音量                AudioPlayer.getInstance().getMediaPlayer().setVolume(1f, 1f);                isPausedByFocusLossTransient = false;                Log.d(TAG, "重新获得焦点");                break;            // 永久丢失焦点，如被其他播放器抢占            case AudioManager.AUDIOFOCUS_LOSS:                PlayerService.stopPlayerService();                abandonAudioFocus();                Log.d(TAG, "永久丢失焦点，如被其他播放器抢占");                break;            // 短暂丢失焦点，如来电            case AudioManager.AUDIOFOCUS_LOSS_TRANSIENT:                AudioPlayer.getInstance().pause();                isPausedByFocusLossTransient = true;                Log.d(TAG, "短暂丢失焦点，如来电");                break;            // 瞬间丢失焦点，如通知            case AudioManager.AUDIOFOCUS_LOSS_TRANSIENT_CAN_DUCK:                // 音量减小为一半                AudioPlayer.getInstance().getMediaPlayer().setVolume(0.5f, 0.5f);                Log.d(TAG, "瞬间丢失焦点，如通知");                break;            default:                break;        }    }}

在初始化MediaPlayer时初始化AudioFocusManager

// 初始化音频焦点管理器AudioFocusManager audioFocusManager = new AudioFocusManager(MyApplication.getContext());

在开始播放的时候获取音频焦点

 // 获取音频焦点if (!audioFocusManager.requestAudioFocus()) {    Log.e(TAG, "获取音频焦点失败");}

在暂定、停止和释放资源的时候取消音频焦点

// 取消音频焦点if (audioFocusManager != null) {        audioFocusManager.abandonAudioFocus();}

4、缓存

这里使用了AndroidVideoCache做本地缓存。
添加AndroidVideoCache依赖

dependencies {    implementation'com.danikula:videocache:2.7.0'}

自定义缓存文件命名规则

public class CacheFileNameGenerator implements FileNameGenerator {    private static final String TAG = "CacheFileNameGenerator";    /**     * @param url     * @return     */    @Override    public String generate(String url) {        Uri uri = Uri.parse(url);        List pathSegList = uri.getPathSegments();        String path = null;        if (pathSegList != null && pathSegList.size() > 0) {            path = pathSegList.get(pathSegList.size() - 1);        } else {            path = url;        }        Log.d(TAG, "generate return " + path);        return path;    }}

创建单例的AndroidVideoCache实例的方法

public class HttpProxyCacheUtil {    private static HttpProxyCacheServer audioProxy;    public static HttpProxyCacheServer getAudioProxy() {        if (audioProxy== null) {            audioProxy= new HttpProxyCacheServer.Builder(MyApplication.getContext())                    .cacheDirectory(CachesUtil.getMediaCacheFile(CachesUtil.AUDIO))                    .maxCacheSize(1024 * 1024 * 1024) // 缓存大小                    .fileNameGenerator(new CacheFileNameGenerator())                    .build();        }        return audioProxy;    }}

使用AndroidVideoCache进行缓存，只要将url经过HttpProxyCacheServer转化就可以了，AndroidVideoCache会处理缓存

String url = "XXXXXXXXXXX";HttpProxyCacheServer proxy = HttpProxyCacheUtil.getAudioProxy()url = proxy.getProxyUrl(url);

5、UI响应

监听播放时不同的状态，并通过广播的形式通知UI做出响应。
创建一个基类的BasePlayReceiver，接收初始化信息完成、资源准备完成、资源播放完成、播放状态改变、缓冲进度和播放错误等广播

public abstract class BasePlayReceiver extends BroadcastReceiver {    public static String ACTION = "com.example.android.myapplication.PLAY_RECEIVER";    public static String EXTRA_TYPE = "type";    public static String TYPE_ON_INIT_SOURCE = "onInitSource";    public static String EXTRA_SOURCE = "source";    public static String TYPE_ON_PREPARED = "onPrepared";    public static String TYPE_ON_COMPLETION = "onCompletion";    public static String TYPE_ON_PLAY_STATUS = "onPlayStatus";    public static String TYPE_ON_BUFFERING_UPDATE = "onBufferingUpdate";    public static String EXTRA_PERCENT = "percent";    public static String TYPE_ON_ERROR = "onError";    public static String EXTRA_WHAT = "what";    public static String EXTRA_EXTRA = "extra";    public static void registerReceiver(Context context, BasePlayReceiver basePlayReceiver) {        IntentFilter filter = new IntentFilter();        filter.addAction(BasePlayReceiver.ACTION);        //注册        context.registerReceiver(basePlayReceiver, filter);    }    public static void unregisterReceiver(Context context, BasePlayReceiver basePlayReceiver) {        if (basePlayReceiver != null) {            context.unregisterReceiver(basePlayReceiver);        }    }    public static void sendBroadcastInitSource(Context context, AlbumProgramItemBean song) {        Intent intent = new Intent();        intent.setAction(BasePlayReceiver.ACTION);        intent.putExtra(BasePlayReceiver.EXTRA_TYPE, TYPE_ON_INIT_SOURCE);        intent.putExtra(BasePlayReceiver.EXTRA_SOURCE, song);        context.sendBroadcast(intent);    }    public static void sendBroadcastPrepared(Context context) {        Intent intent = new Intent();        intent.setAction(BasePlayReceiver.ACTION);        intent.putExtra(BasePlayReceiver.EXTRA_TYPE, TYPE_ON_PREPARED);        context.sendBroadcast(intent);    }    public static void sendBroadcastCompletion(Context context) {        Intent intent = new Intent();        intent.setAction(BasePlayReceiver.ACTION);        intent.putExtra(BasePlayReceiver.EXTRA_TYPE, TYPE_ON_COMPLETION);        context.sendBroadcast(intent);    }    public static void sendBroadcastPlayStatus(Context context) {        Intent intent = new Intent();        intent.setAction(BasePlayReceiver.ACTION);        intent.putExtra(BasePlayReceiver.EXTRA_TYPE, TYPE_ON_PLAY_STATUS);        context.sendBroadcast(intent);    }    public static void sendBroadcastBufferingUpdate(Context context, int percent) {        Intent intent = new Intent();        intent.setAction(BasePlayReceiver.ACTION);        intent.putExtra(BasePlayReceiver.EXTRA_TYPE, TYPE_ON_BUFFERING_UPDATE);        intent.putExtra(BasePlayReceiver.EXTRA_PERCENT, percent);        context.sendBroadcast(intent);    }    public static void sendBroadcastError(Context context, int what, int extra) {        Intent intent = new Intent();        intent.setAction(BasePlayReceiver.ACTION);        intent.putExtra(BasePlayReceiver.EXTRA_TYPE, TYPE_ON_ERROR);        intent.putExtra(BasePlayReceiver.EXTRA_WHAT, what);        intent.putExtra(BasePlayReceiver.EXTRA_EXTRA, extra);        context.sendBroadcast(intent);    }    @Override    public void onReceive(Context context, Intent intent) {        if (!BasePlayReceiver.ACTION.equals(intent.getAction()) || intent.getExtras() == null) {            return;        }        Bundle bundle = intent.getExtras();        String type = bundle.getString(EXTRA_TYPE);        if (TYPE_ON_INIT_SOURCE.equals(type)) {            onInitSource((AlbumProgramItemBean) bundle.getParcelable(EXTRA_SOURCE));        } else if (TYPE_ON_PREPARED.equals(type)) {            onPrepared();        } else if (TYPE_ON_COMPLETION.equals(type)) {            onCompletion();        } else if (TYPE_ON_PLAY_STATUS.equals(type)) {            onPlayStatus();        } else if (TYPE_ON_BUFFERING_UPDATE.equals(type)) {            onBufferingUpdate(bundle.getInt(EXTRA_PERCENT));        } else if (TYPE_ON_ERROR.equals(type)) {            onError(bundle.getInt(EXTRA_WHAT), bundle.getInt(EXTRA_EXTRA));        }    }    /**     * 初始化信息     *     * @param source     */    protected abstract void onInitSource(AlbumProgramItemBean source);    /**     * 资源准备完成     */    protected abstract void onPrepared();    /**     * 资源播放完成     */    protected abstract void onCompletion();    /**     * 播放状态的改变     */    protected abstract void onPlayStatus();    /**     * 缓存进度     *     * @param percent     */    protected abstract void onBufferingUpdate(int percent);    /**     * 播放错误     *     * @param what     * @param extra     */    protected abstract void onError(int what, int extra);}

在需要改变UI的地方，继承BasePlayReceiver，实现其中的方法并动态注册即可。

6、播放控制类

新建单例的音频播放控制类AudioPlayer，方便对音频进行控制，并在操作音频之前都做了状态判断，尽可能的减少错误的发生。在AudioPlayer中可设置播放模式（顺序、列表循环、随机和单曲循环），播放，暂停，上下曲，seekTo，停止,获取播放总时间和获取当前播放进度等功能，并保存全局的播放列表和当前播放的音频，方便获取相关信息。

public class AudioPlayer implements MediaPlayer.OnCompletionListener, MediaPlayer.OnPreparedListener, MediaPlayer.OnBufferingUpdateListener, MediaPlayer.OnErrorListener {    private static final String TAG = "AudioPlayer";    /**     * 播放方式     */    public enum PlayMode {        /**         * 顺序         */        ORDER,        /**         * 列表循环         */        LOOP,        /**         * 随机         */        RANDOM,        /**         * 单曲循环         */        REPEAT    }    private ManagedMediaPlayer mMediaPlayer;    private List mQueue;    private int mQueueIndex;    private PlayMode mPlayMode = PlayMode.ORDER;    private AlbumProgramItemBean nowPlaying;    private WifiManager.WifiLock wifiLock;    private AudioFocusManager audioFocusManager;    private HttpProxyCacheServer proxy;    private static class SingletonHolder {        private static AudioPlayer instance = new AudioPlayer();    }    public static AudioPlayer getInstance() {        return SingletonHolder.instance;    }    @Override    public void onCompletion(MediaPlayer mp) {        BasePlayReceiver.sendBroadcastCompletion(MyApplication.getContext());    }    @Override    public void onPrepared(MediaPlayer mp) {        start();        BasePlayReceiver.sendBroadcastPrepared(MyApplication.getContext());    }    @Override    public void onBufferingUpdate(MediaPlayer mp, int percent) {        BasePlayReceiver.sendBroadcastBufferingUpdate(MyApplication.getContext(), percent);    }    @Override    public boolean onError(MediaPlayer mp, int what, int extra) {        Log.e(TAG, "MediaPlayer onError what " + what + " extra " + extra);        release();        next();        BasePlayReceiver.sendBroadcastError(MyApplication.getContext(), what, extra);        return false;    }    public void init() {        mMediaPlayer = new ManagedMediaPlayer();        // 使用唤醒锁        mMediaPlayer.setWakeMode(MyApplication.getContext(), PowerManager.PARTIAL_WAKE_LOCK);        mMediaPlayer.setAudioStreamType(AudioManager.STREAM_MUSIC);        mMediaPlayer.setOnCompletionListener(this);        mMediaPlayer.setOnPreparedListener(this);        mMediaPlayer.setOnBufferingUpdateListener(this);        mMediaPlayer.setOnErrorListener(this);        // 初始化wifi锁        wifiLock = ((WifiManager) MyApplication.getContext().getApplicationContext().getSystemService(Context.WIFI_SERVICE)).createWifiLock(WifiManager.WIFI_MODE_FULL, "mylock");        // 初始化音频焦点管理器        audioFocusManager = new AudioFocusManager(MyApplication.getContext());        // 初始化AndroidVideoCache        proxy = HttpProxyCacheUtil.getAudioProxy();    }    public void setPlayIndex(int index) {        this.mQueueIndex = index;    }    public void setQueue(List mQueue) {        this.mQueue = mQueue;    }    public void setQueueAndIndex(List mQueue, int mQueueIndex) {        this.mQueue = mQueue;        this.mQueueIndex = mQueueIndex;    }    private void play(AlbumProgramItemBean source) {        if (source == null) {            Log.e(TAG, "没有可用资源");            return;        }        if (mMediaPlayer == null) {            init();        }        if (getStatus() == ManagedMediaPlayer.Status.INITIALIZED) {            Log.e(TAG, "正在准备上一个资源，请稍候");            return;        }        // 更新播放器状态        mMediaPlayer.reset();        nowPlaying = source;        // 更新Notification        Notifier.getInstance().showPlayInfo(source);        // 向MainActivity发送EventBus        EventBus.getDefault().post(new MainActivityEvent());        // 发送初始化资源信息的广告        BasePlayReceiver.sendBroadcastInitSource(MyApplication.getContext(), source);        // 获取音频地址（音频地址一般私有）        Call> call = HttpClientFactory.getAppApiClientInstance().getAlbumAddress(source.getId());        call.enqueue(new Callback>() {            @Override            public void onResponse(Call> call, Response> response) {                if (response.code() == 200 && response.body() != null) {                    if (response.body().getStatus() == 200) {                        String url = response.body().getData();                        url = proxy.getProxyUrl(url);                        play(url);                    }                }            }            @Override            public void onFailure(Call> call, Throwable t) {                BasePlayReceiver.sendBroadcastPrepared(MyApplication.getContext());            }        });    }    private void play(String dataSource) {//        mMediaPlayer.reset();        try {            mMediaPlayer.setDataSource(dataSource);            mMediaPlayer.prepareAsync();        } catch (IOException e) {            e.printStackTrace();            Log.e(TAG, "该资源无法播放");            BasePlayReceiver.sendBroadcastPrepared(MyApplication.getContext());        }    }    private void start() {        // 获取音频焦点        if (!audioFocusManager.requestAudioFocus()) {            Log.e(TAG, "获取音频焦点失败");        }        mMediaPlayer.start();        // 启用wifi锁        wifiLock.acquire();        // 更新notification        Notifier.getInstance().showPlayInfo(nowPlaying);        // 向MainActivity发送EventBus        EventBus.getDefault().post(new MainActivityEvent());        // 发送播放状态的广播        BasePlayReceiver.sendBroadcastPlayStatus(MyApplication.getContext());    }    public void pause() {        if (getStatus() == ManagedMediaPlayer.Status.STARTED) {            mMediaPlayer.pause();            // 关闭wifi锁            if (wifiLock.isHeld()) {                wifiLock.release();            }            // 发送播放状态的广播            BasePlayReceiver.sendBroadcastPlayStatus(MyApplication.getContext());            // 更新notification            Notifier.getInstance().showPlayInfo(nowPlaying);            // 向MainActivity发送EventBus            EventBus.getDefault().post(new MainActivityEvent());            // 取消音频焦点            if (audioFocusManager != null) {                audioFocusManager.abandonAudioFocus();            }        }    }    public void resume() {        if (getStatus() == ManagedMediaPlayer.Status.PAUSED) {            start();        }    }    public void stop() {        if (getStatus() == ManagedMediaPlayer.Status.STARTED                || getStatus() == ManagedMediaPlayer.Status.PAUSED                || getStatus() == ManagedMediaPlayer.Status.COMPLETED) {            mMediaPlayer.stop();            // 发送播放状态的广播            BasePlayReceiver.sendBroadcastPlayStatus(MyApplication.getContext());            // 更新notification            Notifier.getInstance().showPlayInfo(nowPlaying);            // 向MainActivity发送EventBus            EventBus.getDefault().post(new MainActivityEvent());            // 取消音频焦点            if (audioFocusManager != null) {                audioFocusManager.abandonAudioFocus();            }        }    }    public void release() {        if (mMediaPlayer == null) {            return;        }        nowPlaying = null;        Log.d(TAG, "release");        mMediaPlayer.release();        mMediaPlayer = null;        // 取消音频焦点        if (audioFocusManager != null) {            audioFocusManager.abandonAudioFocus();        }        // 关闭wifi锁        if (wifiLock.isHeld()) {            wifiLock.release();        }        wifiLock = null;        audioFocusManager = null;        proxy = null;        // 向MainActivity发送EventBus        EventBus.getDefault().post(new MainActivityEvent());    }    public void seekTo(int msec) {        if (getStatus() == ManagedMediaPlayer.Status.STARTED                || getStatus() == ManagedMediaPlayer.Status.PAUSED                || getStatus() == ManagedMediaPlayer.Status.COMPLETED) {            mMediaPlayer.seekTo(msec);        }    }    /**     * 播放     */    public void play() {        AlbumProgramItemBean albumProgramItemBean = getPlaying(mQueueIndex);        play(albumProgramItemBean);    }    public void next() {        AlbumProgramItemBean albumProgramItemBean = getNextPlaying();        play(albumProgramItemBean);    }    public void previous() {        AlbumProgramItemBean albumProgramItemBean = getPreviousPlaying();        play(albumProgramItemBean);    }    public AlbumProgramItemBean getNowPlaying() {        if (nowPlaying != null) {            return nowPlaying;        } else {            return getPlaying(mQueueIndex);        }    }    public int getCurrentPosition() {        if (getStatus() == ManagedMediaPlayer.Status.STARTED                || getStatus() == ManagedMediaPlayer.Status.PAUSED) {            return mMediaPlayer.getCurrentPosition();        }        return 0;    }    public int getDuration() {        if (getStatus() == ManagedMediaPlayer.Status.STARTED                || getStatus() == ManagedMediaPlayer.Status.PAUSED) {            return mMediaPlayer.getDuration();        }        return 0;    }    public ManagedMediaPlayer.Status getStatus() {        if (mMediaPlayer != null) {            return mMediaPlayer.getState();        } else {            return ManagedMediaPlayer.Status.STOPPED;        }    }    public MediaPlayer getMediaPlayer() {        return mMediaPlayer;    }    public PlayMode getPlayMode() {        return mPlayMode;    }    public void setPlayMode(PlayMode playMode) {        mPlayMode = playMode;    }    public int getQueueIndex() {        return mQueueIndex;    }    public List getQueue() {        return mQueue == null ? new ArrayList() : mQueue;    }    private AlbumProgramItemBean getNextPlaying() {        switch (mPlayMode) {            case ORDER:                mQueueIndex = mQueueIndex + 1;                return getPlaying(mQueueIndex);            case LOOP:                mQueueIndex = (mQueueIndex + 1) % mQueue.size();                return getPlaying(mQueueIndex);            case RANDOM:                mQueueIndex = new Random().nextInt(mQueue.size()) % mQueue.size();                return getPlaying(mQueueIndex);            case REPEAT:                return getPlaying(mQueueIndex);            default:                break;        }        return null;    }    private AlbumProgramItemBean getPreviousPlaying() {        switch (mPlayMode) {            case ORDER:                mQueueIndex = mQueueIndex - 1;                return getPlaying(mQueueIndex);            case LOOP:                mQueueIndex = (mQueueIndex + mQueue.size() - 1) % mQueue.size();                return getPlaying(mQueueIndex);            case RANDOM:                mQueueIndex = new Random().nextInt(mQueue.size()) % mQueue.size();                return getPlaying(mQueueIndex);            case REPEAT:                return getPlaying(mQueueIndex);            default:                break;        }        return null;    }    private AlbumProgramItemBean getPlaying(int index) {        if (mQueue != null && !mQueue.isEmpty() && index >= 0 && index < mQueue.size()) {            return mQueue.get(index);        } else {            return null;        }    }}

7、通知栏

创建通知栏

public class Notifier {    public static final String CHANNEL_ID = "channel_id_audio";    public static final String CHANNEL_NAME = "channel_name_audio";    public static final String CHANNEL_ID_DEFAULT = "channel_id_default";    public static final String EXTRA_NOTIFICATION = "com.sktcm.app.doctor.utils.audio.notification_dark";    private static final int NOTIFICATION_ID = 0x111;    private PlayerService playerService;    private NotificationManager notificationManager;    private boolean isDark;    private String packageName;    public static Notifier getInstance() {        return SingletonHolder.instance;    }    private static class SingletonHolder {        private static Notifier instance = new Notifier();    }    private Notifier() {    }    public void init(PlayerService playerService) {        this.playerService = playerService;        this.notificationManager = (NotificationManager) playerService.getSystemService(NOTIFICATION_SERVICE);        // 前台服务        this.playerService.startForeground(NOTIFICATION_ID, buildNotification(playerService, AudioPlayer.getInstance().getNowPlaying()));        this.packageName = MyApplication.getContext().getPackageName();        this.isDark = isDarkNotificationBar(playerService);    }    public void stopForeground() {        this.playerService.stopForeground(true);    }    public void showPlayInfo(AlbumProgramItemBean source) {        this.notificationManager.notify(NOTIFICATION_ID, buildNotification(playerService, source));    }    private Notification buildNotification(Context context, AlbumProgramItemBean source) {        Intent intent = context.getPackageManager().getLaunchIntentForPackage(packageName);        PendingIntent pendingIntent = PendingIntent.getActivity(context, 0, intent, PendingIntent.FLAG_UPDATE_CURRENT);        //适配安卓8.0的消息渠道        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {            NotificationChannel channel = new NotificationChannel(CHANNEL_ID, CHANNEL_NAME, NotificationManager.IMPORTANCE_LOW);            channel.enableLights(false);            channel.enableVibration(false);            notificationManager.createNotificationChannel(channel);        }        NotificationCompat.Builder builder = new NotificationCompat.Builder(context, CHANNEL_ID)                .setContentIntent(pendingIntent)                .setSmallIcon(R.mipmap.ic_launcher)                .setContent(getRemoteViews(playerService, source));        return builder.build();    }    private RemoteViews getRemoteViews(Context context, AlbumProgramItemBean source) {        int layoutId = isDark ? R.layout.notification_dark : R.layout.notification_light;        final RemoteViews remoteViews = new RemoteViews(context.getPackageName(), layoutId);        if (source == null) {            remoteViews.setTextViewText(R.id.tvTitle, "资源名称");            remoteViews.setViewVisibility(R.id.tvSubtitle, View.GONE);            remoteViews.setViewVisibility(R.id.btnPlay, View.GONE);            remoteViews.setViewVisibility(R.id.btnNext, View.GONE);            remoteViews.setImageViewResource(R.id.ivIcon, R.mipmap.ic_launcher);        } else {            remoteViews.setTextViewText(R.id.tvTitle, source.getName());            remoteViews.setViewVisibility(R.id.btnPlay, View.VISIBLE);            remoteViews.setViewVisibility(R.id.btnNext, View.VISIBLE);            remoteViews.setImageViewResource(R.id.btnPlay, getPlayIconRes());            if (Variables.nowPlayingAlbumData != null && !TextUtils.isEmpty(Variables.nowPlayingAlbumData.getName())) {                remoteViews.setViewVisibility(R.id.tvSubtitle, View.VISIBLE);                remoteViews.setTextViewText(R.id.tvSubtitle, Variables.nowPlayingAlbumData.getName());                Glide.with(context).load(Variables.nowPlayingAlbumData.getHead()).asBitmap().placeholder(R.mipmap.ic_launcher)                        .error(R.drawable.icon_img_err).into(new SimpleTarget(128, 128) {                    @Override                    public void onResourceReady(Bitmap bitmap, GlideAnimation glideAnimation) {                        remoteViews.setImageViewBitmap(R.id.ivIcon, bitmap);                    }                });            } else {                remoteViews.setViewVisibility(R.id.tvSubtitle, View.GONE);                remoteViews.setImageViewResource(R.id.ivIcon, R.mipmap.ic_launcher);            }            Intent playIntent = new Intent(NotificationReceiver.ACTION_STATUS_BAR);            playIntent.putExtra(NotificationReceiver.EXTRA, NotificationReceiver.EXTRA_PLAY);            PendingIntent playPendingIntent = PendingIntent.getBroadcast(context, 1, playIntent, PendingIntent.FLAG_UPDATE_CURRENT);            remoteViews.setOnClickPendingIntent(R.id.btnPlay, playPendingIntent);            Intent nextIntent = new Intent(NotificationReceiver.ACTION_STATUS_BAR);            nextIntent.putExtra(NotificationReceiver.EXTRA, NotificationReceiver.EXTRA_NEXT);            PendingIntent nextPendingIntent = PendingIntent.getBroadcast(context, 2, nextIntent, PendingIntent.FLAG_UPDATE_CURRENT);            remoteViews.setOnClickPendingIntent(R.id.btnNext, nextPendingIntent);        }        return remoteViews;    }    private int getPlayIconRes() {        if (AudioPlayer.getInstance().getStatus() == ManagedMediaPlayer.Status.STARTED) {            return getStartIcon();        } else {            return getPauseIcon();        }    }    private int getStartIcon() {        return isDark ? R.drawable.selector_play : R.drawable.selector_play_light;    }    private int getPauseIcon() {        return isDark ? R.drawable.selector_pause : R.drawable.selector_pause_light;    }    /**********************************************************************************************/    private static final double COLOR_THRESHOLD = 180.0;    private String DUMMY_TITLE = "DUMMY_TITLE";    private int titleColor = 0;    /**     * 判断是否Notification背景是否为黑色     *     * @param context     * @return     */    public boolean isDarkNotificationBar(Context context) {        return !isColorSimilar(Color.BLACK, getNotificationTitleColor(context));    }    /**     * 获取Notification 标题的颜色     *     * @param context     * @return     */    private int getNotificationTitleColor(Context context) {        int color = 0;        if (context instanceof AppCompatActivity) {            color = getNotificationColorCompat(context);        } else {            color = getNotificationColorInternal(context);        }        return color;    }    /**     * 判断颜色是否相似     *     * @param baseColor     * @param color     * @return     */    public boolean isColorSimilar(int baseColor, int color) {        int simpleBaseColor = baseColor | 0xff000000;        int simpleColor = color | 0xff000000;        int baseRed = Color.red(simpleBaseColor) - Color.red(simpleColor);        int baseGreen = Color.green(simpleBaseColor) - Color.green(simpleColor);        int baseBlue = Color.blue(simpleBaseColor) - Color.blue(simpleColor);        double value = Math.sqrt(baseRed * baseRed + baseGreen * baseGreen + baseBlue * baseBlue);        return value < COLOR_THRESHOLD;    }    /**     * 获取标题颜色     *     * @param context     * @return     */    private int getNotificationColorInternal(Context context) {        NotificationCompat.Builder builder = new NotificationCompat.Builder(context, CHANNEL_ID_DEFAULT);        builder.setContentTitle(DUMMY_TITLE);        Notification notification = builder.build();        RemoteViews contentView = notification.contentView;        if (contentView != null) {            ViewGroup notificationRoot = (ViewGroup) contentView.apply(context, new FrameLayout(context));            TextView title = (TextView) notificationRoot.findViewById(android.R.id.title);            if (title == null) {                //如果ROM厂商更改了默认的id                iteratorView(notificationRoot, new Filter() {                    @Override                    public void filter(View view) {                        if (view instanceof TextView) {                            TextView textView = (TextView) view;                            if (DUMMY_TITLE.equals(textView.getText().toString())) {                                titleColor = textView.getCurrentTextColor();                            }                        }                    }                });                return titleColor == 0 ? Color.WHITE : titleColor;            } else {                return title.getCurrentTextColor();            }        } else {            return Color.BLACK;        }    }    private int getNotificationColorCompat(Context context) {        NotificationCompat.Builder builder = new NotificationCompat.Builder(context);        Notification notification = builder.build();        int layoutId = notification.contentView.getLayoutId();        ViewGroup notificationRoot = (ViewGroup) LayoutInflater.from(context).inflate(layoutId, null);        TextView title = (TextView) notificationRoot.findViewById(android.R.id.title);        if (title == null) {            final List textViews = new ArrayList<>();            iteratorView(notificationRoot, new Filter() {                @Override                public void filter(View view) {                    if (view instanceof TextView) {                        textViews.add((TextView) view);                    }                }            });            float minTextSize = Integer.MIN_VALUE;            int index = 0;            for (int i = 0, j = textViews.size(); i < j; i++) {                float currentSize = textViews.get(i).getTextSize();                if (currentSize > minTextSize) {                    minTextSize = currentSize;                    index = i;                }            }            textViews.get(index).setText(DUMMY_TITLE);            return textViews.get(index).getCurrentTextColor();        } else {            return title.getCurrentTextColor();        }    }    private void iteratorView(View view, Filter filter) {        if (view == null || filter == null) {            return;        }        filter.filter(view);        if (view instanceof ViewGroup) {            ViewGroup container = (ViewGroup) view;            for (int i = 0, j = container.getChildCount(); i < j; i++) {                View child = container.getChildAt(i);                iteratorView(child, filter);            }        }    }    interface Filter {        void filter(View view);    }}

操作通知栏的按钮时发送广播，自定义NotificationReceiver,并静态注册，在NotificationReceiver中控制音频播放

public class NotificationReceiver extends BroadcastReceiver {    public static final String ACTION_STATUS_BAR = "com.sktcm.app.doctor.utils.audio.NOTIFICATION_ACTIONS";    public static final String EXTRA = "extra";    public static final String EXTRA_PLAY = "play_pause";    public static final String EXTRA_NEXT= "play_next";    @Override    public void onReceive(Context context, Intent intent) {        if (intent == null || TextUtils.isEmpty(intent.getAction())) {            return;        }        String extra = intent.getStringExtra(EXTRA);        if (EXTRA_PLAY.equals(extra)) {            if (AudioPlayer.getInstance().getStatus() == ManagedMediaPlayer.Status.STARTED) {                AudioPlayer.getInstance().pause();            } else if (AudioPlayer.getInstance().getStatus() == ManagedMediaPlayer.Status.PAUSED){                AudioPlayer.getInstance().resume();            }        } else if (EXTRA_NEXT.equals(extra)){            AudioPlayer.getInstance().next();        }    }}

8、前台服务

使用前台服务开始播放音频

public class PlayerService extends Service {    private static String ACTION_START = "ACTION_START";    private static String ACTION_PREVIOUS = "ACTION_PREVIOUS";    private static String ACTION_NEXT = "ACTION_NEXT";    private static String ACTION_GONE = "ACTION_GONE";    private static String ACTION_STOP = "ACTION_STOP";    public static void startPlayerService() {        Intent intent = new Intent(MyApplication.getContext(), PlayerService.class);        intent.setAction(ACTION_START);        MyApplication.getContext().startService(intent);    }    public static void playerPreviousService() {        Intent intent = new Intent(MyApplication.getContext(), PlayerService.class);        intent.setAction(ACTION_PREVIOUS);        MyApplication.getContext().startService(intent);    }    public static void playerNextService() {        Intent intent = new Intent(MyApplication.getContext(), PlayerService.class);        intent.setAction(ACTION_NEXT);        MyApplication.getContext().startService(intent);    }    public static void stopPlayerService() {        Intent intent = new Intent(MyApplication.getContext(), PlayerService.class);        MyApplication.getContext().stopService(intent);    }    @Override    public void onCreate() {        super.onCreate();        // 开始前台服务        Notifier.getInstance().init(this);    }    @Nullable    @Override    public IBinder onBind(Intent intent) {        return null;    }    @Override    public int onStartCommand(Intent intent, int flags, int startId) {        if (intent != null && intent.getAction() != null) {            if (ACTION_START.equals(intent.getAction())) {                AudioPlayer.getInstance().play ();            } else if (ACTION_PREVIOUS.equals(intent.getAction())) {                AudioPlayer.getInstance().previous();            } else if (ACTION_NEXT.equals(intent.getAction())) {                AudioPlayer.getInstance().next();            }        }        return START_NOT_STICKY;    }    @Override    public void onDestroy() {        super.onDestroy();        AudioPlayer.getInstance().release();        Notifier.getInstance().stopForeground();    }}

9、开始播放

传入播放列表，并开始服务即可播放

AudioPlayer.getInstance().setQueueAndIndex(list, 0);PlayerService.startPlayerService();