java - 音乐服务在按下后退按钮时停止

Question

我有一个带有一个 fragment 的 actionbaractivity和一个服务类，它是从 url 流式传输音乐。下面我粘贴一些代码以供引用

TopTenFragment.java

public class ToptenFragment extends Fragment {

    private ListView TrackList;
    private CustomAdapter songadapter;
    private ArrayList<Song> songList;


    int currentduration;
    ArrayList<Integer> buttonposiotion = new ArrayList<Integer>();
    private int curBtnIndex = -1;
    // private boolean paused = false;
    private int lastpos;
    // service
    private MyService musicSrv;
    private Intent playIntent;
    // binding
    private boolean musicBound = false;
    // activity and playback pause flags
    private boolean paused = false, playbackPaused = false;

    int i = 0;
    int start = 0;
    String urlindex;
    public ImageView imageView;
    private ProgressBar bar;
    private WeakReference<Activity> mainActivityWeakRef;

    @Override
    public void onActivityCreated(Bundle savedInstanceState) {
        super.onActivityCreated(savedInstanceState);
        System.out.println("onActivityCreated");
        mainActivityWeakRef = new WeakReference<Activity>(
                (Activity) getActivity());
        if (mainActivityWeakRef.get() != null
                && !mainActivityWeakRef.get().isFinishing()) {
            getData();
        }
        SharedPreferences onStopPf = getActivity().getSharedPreferences(
                "On Stop", 0);
        Editor stEditor = onStopPf.edit();
        curBtnIndex = onStopPf.getInt("btnIndex", -1);
        stEditor.commit();
        System.out.println("curt index from top -> " + curBtnIndex);
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
            Bundle savedInstanceState) {
        System.out.println("onCreateView");
        View v = inflater.inflate(R.layout.main, container, false);
        initLayout(v);
        return v;
    }

    private void initLayout(View v) {
        TrackList = (ListView) v.findViewById(R.id.songList);
        // get image for ad
        imageView = (ImageView) v.findViewById(R.id.radio_adview);
        bar = (ProgressBar) v.findViewById(R.id.load);
    }

    public void getData() {
        Map<String, String> map = new HashMap<String, String>();
        map.put("url", getActivity().getString(R.string.get_song));
        new GetData(map);
    }

    public class CustomAdapter extends BaseAdapter {
        private ArrayList<Song> songListLocal;
        public Activity context;
        // Song s;

        public LayoutInflater inflater;

        public CustomAdapter(Activity context, ArrayList<Song> arr_calllog_name) {
            super();
            this.context = context;
            this.songListLocal = arr_calllog_name;
            inflater = (LayoutInflater) getActivity().getSystemService(
                    Context.LAYOUT_INFLATER_SERVICE);
        }

        @Override
        public int getCount() {
            return songListLocal.size();
        }

        @Override
        public Object getItem(int arg0) {
            return arg0;
        }

        @Override
        public long getItemId(int arg0) {
            return arg0;
        }

        @Override
        public View getView(final int position, View convertView,
                ViewGroup parent) {
            ImageView song_thumb;
            TextView txtName, songNumTxt;
            final Button playbutton;
            final Button stopbutton;
            final Button pausebutton;

            View view = convertView;
            final Song s = songListLocal.get(position);

            view = inflater.inflate(R.layout.list_item, null);
            song_thumb = (ImageView) view.findViewById(R.id.songthumb);
            txtName = (TextView) view.findViewById(R.id.songname);
            songNumTxt = (TextView) view.findViewById(R.id.songNum);
            playbutton = (Button) view.findViewById(R.id.playbutton);
            stopbutton = (Button) view.findViewById(R.id.stopbutton);
            pausebutton = (Button) view.findViewById(R.id.pausebutton);

            Picasso.with(getActivity()).load(s.getSong_icon()).into(song_thumb);

            txtName.setText(s.getName());
            songNumTxt.setText(String.valueOf(s.getSongNum()));
            playbutton.setOnClickListener(new View.OnClickListener() {

                @Override
                public void onClick(View v) {
                    curBtnIndex = position;

                    songPicked(position);
                    setlistview();
                    playbutton.setVisibility(View.INVISIBLE);
                    pausebutton.setVisibility(View.VISIBLE);
                    stopbutton.setVisibility(View.VISIBLE);
                }
            });
            pausebutton.setOnClickListener(new OnClickListener() {
                @Override
                public void onClick(View v) {
                    //pause
                }
            });
            stopbutton.setOnClickListener(new OnClickListener() {
                @Override
                public void onClick(View v1) {
                    try {
                        paused = false;
                        playbutton.setVisibility(View.VISIBLE);
                        pausebutton.setVisibility(View.INVISIBLE);
                        stopbutton.setVisibility(View.INVISIBLE);
                    } catch (Exception e) {
                        System.out.println("exception in pause");
                    }
                }
            });
            if (curBtnIndex == position) {
                pausebutton.setVisibility(View.VISIBLE);
                stopbutton.setVisibility(View.VISIBLE);
                playbutton.setVisibility(View.INVISIBLE);
            } else {
                pausebutton.setVisibility(View.INVISIBLE);
                stopbutton.setVisibility(View.INVISIBLE);
            }
            return view;
        }
    }

    // user song select
    public void songPicked(int pos) {
        musicSrv.setSong(pos);
        musicSrv.playSong();
        if (playbackPaused) {
            playbackPaused = false;
        }
    }

    public void setlistview() {
        TrackList.setAdapter(songadapter);
        TrackList.setSelection(curBtnIndex);
    }

    private class GetData {
        private final Map<String, String> map;

        public GetData(Map<String, String> map2) {
            this.map = map2;
            new AsynRequest().execute(map.get("url"));
        }

        class AsynRequest extends AsyncTask<String, Void, String> {

            @Override
            protected void onPreExecute() {
            }

            @Override
            protected String doInBackground(String... urls) {
                map.remove("url");
                HttpPost httppost = new HttpPost(urls[0]);

                try {

                    HttpClient httpclient = new DefaultHttpClient();

                    List<NameValuePair> nameValuePairs = new ArrayList<NameValuePair>();

                    for (String key : map.keySet()) {
                        System.out.println(key + "  < === >  " + map.get(key));

                        nameValuePairs.add(new BasicNameValuePair(key, map
                                .get(key)));
                    }

                    httppost.setEntity(new UrlEncodedFormEntity(nameValuePairs,
                            "UTF-8"));

                    HttpResponse response = httpclient.execute(httppost);

                    String responseBody = EntityUtils.toString(response
                            .getEntity());

                    return responseBody;
                } catch (UnknownHostException e) {
                    e.printStackTrace();
                } catch (ClientProtocolException e) {
                    e.printStackTrace();
                } catch (IOException e) {
                    e.printStackTrace();
                }

                return null;

            }

            @Override
            protected void onPostExecute(String result) {
                // System.out.println("result of songs -> " + result);
                bar.setVisibility(View.GONE);
                if (result != null) {
                    try {
                        JSONObject jObject = new JSONObject(result);
                        String result1 = jObject.getString("result");
                        if (result1.equals("success")) {
                            JSONArray jArray = jObject.getJSONArray("songs");
                            songList = null;
                            songList = new ArrayList<Song>();
                            for (int i = 0; i < jArray.length(); i++) {
                                JSONObject j = jArray.getJSONObject(i);
                                Song s = new Song();
                                String song_icon_path = j
                                        .getString("song_icon");
                                String name = j.getString("name");
                                String song_file_path = j.getString("song_url");

                                s.setSong_icon(song_icon_path);
                                s.setName(name);
                                s.setSong_url(song_file_path);

                                int n = i + 1;
                                s.setSongNum(n);
                                songList.add(s);
                            }
                            if (songList != null) {
                                System.out.println("song list size -> "
                                        + songList.size());
                                mainActivityWeakRef = new WeakReference<Activity>(
                                        (Activity) getActivity());
                                if (mainActivityWeakRef.get() != null
                                        && !mainActivityWeakRef.get()
                                                .isFinishing()) {
                                    songadapter = new CustomAdapter(
                                            getActivity(), songList);
                                    TrackList.setAdapter(songadapter);

                                    if (playIntent == null) {
                                        playIntent = new Intent(getActivity(),
                                                MyService.class);
                                        musicBound = getActivity().bindService(
                                                playIntent, musicConnection,
                                                Context.BIND_AUTO_CREATE);
                                        System.out.println("service bound -> "
                                                + musicBound);
                                        getActivity().startService(playIntent);
                                    }
                                }

                            } else {
                                System.out.println("song list null");
                            }
                        }
                    } catch (JSONException e) {
                        e.printStackTrace();
                        bar.setVisibility(View.GONE);
                    }
                }
                super.onPostExecute(result);
            }
        }
    }

    @Override
    public void onDestroyView() {
        System.out.println("onDestroyView()");
        boolean s = isMyServiceRunning(MyService.class);
        System.out.println("runnind ? " + s);
        if (musicBound) {
            musicBound = false;
            getActivity().unbindService(musicConnection);
        } else
            System.out.println("not bound");
        super.onDestroyView();
    }

    private boolean isMyServiceRunning(Class<?> serviceClass) {
        ActivityManager manager = (ActivityManager) getActivity()
                .getSystemService(Context.ACTIVITY_SERVICE);
        for (RunningServiceInfo service : manager
                .getRunningServices(Integer.MAX_VALUE)) {
            if (serviceClass.getName().equals(service.service.getClassName())) {
                return true;
            }
        }
        return false;
    }

    // connect to the service
    private ServiceConnection musicConnection = new ServiceConnection() {
        @Override
        public void onServiceConnected(ComponentName name, IBinder service) {
            MyBinder binder = (MyBinder) service;
            // get service
            musicSrv = binder.getService();
            // pass list
            musicSrv.setList(songList);
            musicBound = true;
        }

        @Override
        public void onServiceDisconnected(ComponentName name) {
            musicBound = false;
        }
    };

我的服务.java

public class MyService extends Service implements OnCompletionListener,
        OnErrorListener, OnPreparedListener {
    // media player
    private MediaPlayer player;
    // song list
    private ArrayList<Song> songs;
    // current position
    private int songPosn;
    // binder
    private final IBinder musicBind = new MyBinder();
    // title of current song
    private String songTitle = "";
    // notification id
    private static final int NOTIFY_ID = 1;

    @Override
    public void onCreate() {
        // create the service
        super.onCreate();
        // initialize position
        songPosn = 0;
        // create player
        player = new MediaPlayer();
        // initialize
        initMusicPlayer();
    }

    public void initMusicPlayer() {
        // set player properties
        player.setWakeMode(getApplicationContext(),
                PowerManager.PARTIAL_WAKE_LOCK);
        player.setAudioStreamType(AudioManager.STREAM_MUSIC);
        // set listeners
        player.setOnPreparedListener(this);
        player.setOnCompletionListener(this);
        player.setOnErrorListener(this);
    }

    @Override
    public int onStartCommand(Intent intent, int flags, int startId) {
        return START_STICKY;
    }

    // pass song list
    public void setList(ArrayList<Song> theSongs) {
        songs = theSongs;
    }

    // binder
    public class MyBinder extends Binder {
        MyService getService() {
            return MyService.this;
        }
    }

    // activity will bind to service
    @Override
    public IBinder onBind(Intent intent) {
        return musicBind;
    }

    // release resources when unbind
    @Override
    public boolean onUnbind(Intent intent) {
        player.stop();
        player.release();
        return false;
    }

    // play a song
    public void playSong() {
        // play
        player.reset();
        // get song
        Song playSong = songs.get(songPosn);
        // get title
        songTitle = playSong.getName();

        String trackUri = playSong.getSong_url();
        System.out.println("track uri -> " + trackUri);
        // set the data source
        try {
            player.setDataSource(trackUri);
        } catch (Exception e) {
            Log.e("MUSIC SERVICE", "Error setting data source", e);
        }
        player.prepareAsync();
    }

    // set the song
    public void setSong(int songIndex) {
        songPosn = songIndex;
    }

    @Override
    public void onCompletion(MediaPlayer mp) {
        // check if playback has reached the end of a track
        if (player.getCurrentPosition() > 0) {
            mp.reset();
        }
    }

    @Override
    public boolean onError(MediaPlayer mp, int what, int extra) {
        Log.v("MUSIC PLAYER", "Playback Error");
        mp.reset();
        return false;
    }

    @Override
    public void onPrepared(MediaPlayer mp) {
        playMusic();
    }

    @Override
    public void onDestroy() {
        Log.e("MUSIC PLAYER", "onDestroy()");
        stopForeground(true);
    }

    public void playMusic() {
        player.start();
        // notification
        Intent notIntent = new Intent(this, MainActivity.class);
        PendingIntent pendInt = PendingIntent.getActivity(this, 0, notIntent,
                PendingIntent.FLAG_UPDATE_CURRENT);

        Notification.Builder builder = new Notification.Builder(this);

        builder.setContentIntent(pendInt).setSmallIcon(R.drawable.ic_launcher)
                .setTicker(songTitle).setOngoing(true)
                .setContentTitle("Playing").setContentText(songTitle);
        Notification not = builder.build();
        startForeground(NOTIFY_ID, not);
    }

}

音乐播放效果很好，但当我在设备上按下时，它会停止播放音乐。我的问题是，如果用户按下硬件后退按钮，我想继续在后台播放音乐。

任何帮助将不胜感激谢谢

Answer 1

您正在解除与 onDestroyView 中服务的绑定(bind)。当最后一个 ServiceConnection 解除绑定(bind)时，将在 Service 上调用 onUnbind 方法。您的 onUnbind 实现停止播放。相反，您应该在前台通知中包含播放控件，并通过针对您的服务类的 PendingIntent 来控制播放。