1. 程式人生 > >Android 使用MediaPlayer播放網路音訊

Android 使用MediaPlayer播放網路音訊

一、前言

MediaPlayer是Android自帶的一個多媒體播放類,可以播放音視訊流或者本地音視訊檔案。MediaPlayer方法的呼叫需要在一定的狀態下,下圖是一個MediaPlayer物件被支援的播放控制操作驅動的宣告週期和狀態。其中,橢圓代表MediaPlayer可能駐留的狀態,弧線表示驅動MediaPlayer在各個狀態之間遷移的播放控制操作。這裡有兩種型別的弧線。由單箭頭開始的弧線代表同步方法呼叫,而以雙箭頭開頭的弧線代表非同步方法呼叫。圖片介紹來源於官方文。
這裡寫圖片描述
詳細介紹可通過Android – 多媒體播放之MediaPlayer基礎簡介瞭解更多

二、播放網路音訊

現在寫一個支援本地快取的網路音訊播放器,並添加了喚醒鎖、WiFi鎖和音訊焦點等功能。

1、自定義MediaPlayer

直接通過MediaPlayer獲取播放狀態有時不夠準確,所以自定義ManagedMediaPlayer繼承MediaPlayer,拓展MediaPlayer的功能,控制播放狀態

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、喚醒鎖、WiFi鎖

app在長時間後臺執行時,手機有可能會進入休眠,這是CUP和WiFi可能會停止執行,影響到app的正常執行,所以我們需要加入喚醒鎖和WiFi鎖保證我們在後臺長時間播放音訊的穩定。
初始化時MediaPlayer時使用喚醒鎖並初始化WiFi鎖

// 使用喚醒鎖
mMediaPlayer.setWakeMode(MyApplication.getContext(), PowerManager.PARTIAL_WAKE_LOCK);
// 初始化wifi鎖
WifiManager.WifiLock wifiLock = ((WifiManager) MyApplication.getContext().getApplicationContext().getSystemService(Context.WIFI_SERVICE)).createWifiLock(WifiManager.WIFI_MODE_FULL, "mylock");

在開始播放的時候啟用WiFi鎖

// 啟用wifi鎖
wifiLock.acquire();

在暫定和釋放資源的時候關閉WiFi鎖

// 關閉wifi鎖
if (wifiLock.isHeld()) {
    wifiLock.release();
}

3、音訊焦點

Android系統是一個多工作業系統,因此同一時刻允許許多工同時工作。但是這對音訊類應用來說是個挑戰,因為如果多個音訊同時播放的話,很多情況下使用者體驗會相當的差。當你需要播放音樂或者傳送一個通知的時候,你可以去要求獲得音訊焦點。一旦獲得,就可以自由的使用音訊輸出裝置。但是同時它也在時時刻刻的監聽著音訊焦點的變化。當音訊焦點變化時,你需要去合適的處理你的音訊輸出。
自定義AudioFocusManager實現音訊焦點變化監聽

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) {
            // 重新獲得焦點
            case AudioManager.AUDIOFOCUS_GAIN:
                if (isPausedByFocusLossTransient) {
                    // 通話結束,恢復播放
                    AudioPlayer.getInstance().resume();
                }
                // 恢復音量
                AudioPlayer.getInstance().getMediaPlayer().setVolume(1f, 1f);
                isPausedByFocusLossTransient = false;
                Log.d(TAG, "重新獲得焦點");
                break;
            // 永久丟失焦點,如被其他播放器搶佔
            case AudioManager.AUDIOFOCUS_LOSS:
                PlayerService.stopPlayerService();
                abandonAudioFocus();
                Log.d(TAG, "永久丟失焦點,如被其他播放器搶佔");
                break;
            // 短暫丟失焦點,如來電
            case AudioManager.AUDIOFOCUS_LOSS_TRANSIENT:
                AudioPlayer.getInstance().pause();
                isPausedByFocusLossTransient = true;
                Log.d(TAG, "短暫丟失焦點,如來電");
                break;
            // 瞬間丟失焦點,如通知
            case AudioManager.AUDIOFOCUS_LOSS_TRANSIENT_CAN_DUCK:
                // 音量減小為一半
                AudioPlayer.getInstance().getMediaPlayer().setVolume(0.5f, 0.5f);
                Log.d(TAG, "瞬間丟失焦點,如通知");
                break;
            default:
                break;
        }

    }
}

在初始化MediaPlayer時初始化AudioFocusManager

// 初始化音訊焦點管理器
AudioFocusManager audioFocusManager = new AudioFocusManager(MyApplication.getContext());

在開始播放的時候獲取音訊焦點

 // 獲取音訊焦點
if (!audioFocusManager.requestAudioFocus()) {
    Log.e(TAG, "獲取音訊焦點失敗");
}

在暫定、停止和釋放資源的時候取消音訊焦點

// 取消音訊焦點
if (audioFocusManager != null) {
        audioFocusManager.abandonAudioFocus();
}

4、快取

這裡使用了AndroidVideoCache做本地快取。
新增AndroidVideoCache依賴

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

自定義快取檔案命名規則

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<String> 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;
    }
}

建立單例的AndroidVideoCache例項的方法

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) // 快取大小
                    .fileNameGenerator(new CacheFileNameGenerator())
                    .build();
        }
        return audioProxy;
    }
}

使用AndroidVideoCache進行快取,只要將url經過HttpProxyCacheServer轉化就可以了,AndroidVideoCache會處理快取

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

5、UI響應

監聽播放時不同的狀態,並通過廣播的形式通知UI做出響應。
建立一個基類的BasePlayReceiver,接收初始化資訊完成、資源準備完成、資源播放完成、播放狀態改變、緩衝進度和播放錯誤等廣播

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);
        //註冊
        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));
        }
    }

    /**
     * 初始化資訊
     *
     * @param source
     */
    protected abstract void onInitSource(AlbumProgramItemBean source);

    /**
     * 資源準備完成
     */
    protected abstract void onPrepared();

    /**
     * 資源播放完成
     */
    protected abstract void onCompletion();

    /**
     * 播放狀態的改變
     */
    protected abstract void onPlayStatus();

    /**
     * 快取進度
     *
     * @param percent
     */
    protected abstract void onBufferingUpdate(int percent);

    /**
     * 播放錯誤
     *
     * @param what
     * @param extra
     */
    protected abstract void onError(int what, int extra);
}

在需要改變UI的地方,繼承BasePlayReceiver,實現其中的方法並動態註冊即可。

6、播放控制類

新建單例的音訊播放控制類AudioPlayer,方便對音訊進行控制,並在操作音訊之前都做了狀態判斷,儘可能的減少錯誤的發生。在AudioPlayer中可設定播放模式(順序、列表迴圈、隨機和單曲迴圈),播放,暫停,上下曲,seekTo,停止,獲取播放總時間和獲取當前播放進度等功能,並儲存全域性的播放列表和當前播放的音訊,方便獲取相關資訊。

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 {
        /**
         * 順序
         */
        ORDER,
        /**
         * 列表迴圈
         */
        LOOP,
        /**
         * 隨機
         */
        RANDOM,
        /**
         * 單曲迴圈
         */
        REPEAT
    }

    private ManagedMediaPlayer mMediaPlayer;
    private List<AlbumProgramItemBean> 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();
        // 使用喚醒鎖
        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鎖
        wifiLock = ((WifiManager) MyApplication.getContext().getApplicationContext().getSystemService(Context.WIFI_SERVICE)).createWifiLock(WifiManager.WIFI_MODE_FULL, "mylock");
        // 初始化音訊焦點管理器
        audioFocusManager = new AudioFocusManager(MyApplication.getContext());
        // 初始化AndroidVideoCache
        proxy = HttpProxyCacheUtil.getAudioProxy();
    }


    public void setPlayIndex(int index) {
        this.mQueueIndex = index;
    }

    public void setQueue(List<AlbumProgramItemBean> mQueue) {
        this.mQueue = mQueue;
    }

    public void setQueueAndIndex(List<AlbumProgramItemBean> mQueue, int mQueueIndex) {
        this.mQueue = mQueue;
        this.mQueueIndex = mQueueIndex;
    }

    private void play(AlbumProgramItemBean source) {
        if (source == null) {
            Log.e(TAG, "沒有可用資源");
            return;
        }
        if (mMediaPlayer == null) {
            init();
        }
        if (getStatus() == ManagedMediaPlayer.Status.INITIALIZED) {
            Log.e(TAG, "正在準備上一個資源,請稍候");
            return;
        }
        // 更新播放器狀態
        mMediaPlayer.reset();

        nowPlaying = source;
        // 更新Notification
        Notifier.getInstance().showPlayInfo(source);
        // 向MainActivity傳送EventBus
        EventBus.getDefault().post(new MainActivityEvent());
        // 傳送初始化資源資訊的廣告
        BasePlayReceiver.sendBroadcastInitSource(MyApplication.getContext(), source);
        // 獲取音訊地址(音訊地址一般私有)
        Call<BaseCallBackVo<String>> call = HttpClientFactory.getAppApiClientInstance().getAlbumAddress(source.getId());
        call.enqueue(new Callback<BaseCallBackVo<String>>() {
            @Override
            public void onResponse(Call<BaseCallBackVo<String>> call, Response<BaseCallBackVo<String>> 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<BaseCallBackVo<String>> 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, "該資源無法播放");
            BasePlayReceiver.sendBroadcastPrepared(MyApplication.getContext());
        }
    }

    private void start() {
        // 獲取音訊焦點
        if (!audioFocusManager.requestAudioFocus()) {
            Log.e(TAG, "獲取音訊焦點失敗");
        }
        mMediaPlayer.start();
        // 啟用wifi鎖
        wifiLock.acquire();
        // 更新notification
        Notifier.getInstance().showPlayInfo(nowPlaying);
        // 向MainActivity傳送EventBus
        EventBus.getDefault().post(new MainActivityEvent());
        // 傳送播放狀態的廣播
        BasePlayReceiver.sendBroadcastPlayStatus(MyApplication.getContext());
    }

    public void pause() {
        if (getStatus() == ManagedMediaPlayer.Status.STARTED) {
            mMediaPlayer.pause();
            // 關閉wifi鎖
            if (wifiLock.isHeld()) {
                wifiLock.release();
            }
            // 傳送播放狀態的廣播
            BasePlayReceiver.sendBroadcastPlayStatus(MyApplication.getContext());
            // 更新notification
            Notifier.getInstance().showPlayInfo(nowPlaying);
            // 向MainActivity傳送EventBus
            EventBus.getDefault().post(new MainActivityEvent());
            // 取消音訊焦點
            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();
            // 傳送播放狀態的廣播
            BasePlayReceiver.sendBroadcastPlayStatus(MyApplication.getContext());
            // 更新notification
            Notifier.getInstance().showPlayInfo(nowPlaying);
            // 向MainActivity傳送EventBus
            EventBus.getDefault().post(new MainActivityEvent());
            // 取消音訊焦點
            if (audioFocusManager != null) {
                audioFocusManager.abandonAudioFocus();
            }
        }
    }

    public void release() {
        if (mMediaPlayer == null) {
            return;
        }
        nowPlaying = null;
        Log.d(TAG, "release");
        mMediaPlayer.release();
        mMediaPlayer = null;
        // 取消音訊焦點
        if (audioFocusManager != null) {
            audioFocusManager.abandonAudioFocus();
        }
        // 關閉wifi鎖
        if (wifiLock.isHeld()) {
            wifiLock.release();
        }
        wifiLock = null;
        audioFocusManager = null;
        proxy = null;
        // 向MainActivity傳送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<AlbumProgramItemBean> getQueue() {
        return mQueue == null ? new ArrayList<AlbumProgramItemBean>() : 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、通知欄

建立通知欄

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);
        // 前臺服務
        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);

        //適配安卓8.0的訊息渠道
        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, "資源名稱");
            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<Bitmap>(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;

    /**
     * 判斷是否Notification背景是否為黑色
     *
     * @param context
     * @return
     */
    public boolean isDarkNotificationBar(Context context) {
        return !isColorSimilar(Color.BLACK, getNotificationTitleColor(context));
    }

    /**
     * 獲取Notification 標題的顏色
     *
     * @param context
     * @return
     */
    private int getNotificationTitleColor(Context context) {
        int color = 0;
        if (context instanceof AppCompatActivity) {
            color = getNotificationColorCompat(context);
        } else {
            color = getNotificationColorInternal(context);
        }
        return color;
    }

    /**
     * 判斷顏色是否相似
     *
     * @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;

    }

    /**
     * 獲取標題顏色
     *
     * @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廠商更改了預設的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.getLayo