Android- Resuming Service in Activity and destroying them on destroy_问答_开发者

I currently have an Activty that when created starts and binds with a service. This service has a mediaplayer. What I would like to do is if the activity is resumed then the service keeps playing, etc. When the activity is destroyed, it should stop the service. So far I can get both the service to keep playing when activity is re-activated and the service to stop when a new activity is created but not both together. Any suggestions or ideas? Thanks. Code below:

Activity class:

public class DUBAudioActivity extends Activity{

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

    Button playPauseButtonDUB;
    Intent playbackServiceIntentDUB;


    public void onCreate(Bundle savedInstanceState){
        super.onCreate(savedInstanceState);
        setContentView(R.layout.sdrplaylist_dubstep);

        playPauseButtonDUB = (Button)findViewById(R.id.playpausebuttonDUB);

        playbackServiceIntentDUB = new Intent(this, DUBAudioService.class);
        Log.d(TAG, "created intent");

        startService(playbackServiceIntentDUB);

        Log.d(TAG, "bound service");
        //
        //set button text
         playPauseButtonDUB.setText("Pause");
         //set button tag
        playPauseButtonDUB.setTag(1);



        playPauseButtonDUB.setOnClickListener(new OnClickListener(){

            @Override
            public void onClick(View v) {
                //set the tag stuff
                final int status = (Integer) v.getTag();
                //create if statement for the button to do play and pause
                if(status==1){
                    playPauseButtonDUB.setText("Play");
                    v.setTag(0);
                    Log.d(TAG, "set tag to 0");
                    baServiceDUB.pauseSong();
                    Log.d(TAG, "pause song");   
                }else{
                    playPauseButtonDUB.setText("Pause");
                    v.setTag(1);
                    Log.d(TAG, "set tag to 1");
                    baServiceDUB.playSong();
                    Log.d(TAG, "song play'd");
                }

            }

        });
    //
    }
    private DUBAudioService baServiceDUB;

    private ServiceConnection serviceConnectionDUB = new ServiceConnection(){
        public void onServiceConnected(ComponentName className, IBinder baBinder) {
            baServiceDUB =
            ((DUBAudioService.DUBBackgroundAudioServiceBinder)baBinder).getService();
        }

        public void onServiceDisconnected(ComponentName className){
            baServiceDUB = null;
        }
//
    };

    void doBindService(){
        getApplicationContext().bindService(playbackServiceIntentDUB, serviceConnectionDUB,
                Context.BIND_AUTO_CREATE);
        Log.d(TAG, "do bind service");

    }

    @Override
    public void onResume() {
        getApplicationContext().bindService(playbackServiceIntentDUB, serviceConnectionDUB,
                Context.BIND_AUTO_CREATE);
            Log.d(TAG, "on resume + re-bound service");
        super.onResume();
    }

    @Override
    public void onDestroy(){
        stopService(playbackServiceIntentDUB);
        getApplicationContext().unbindService(serviceConnectionDUB);

        Log.d(TAG, "destroy'd + unbind service");
        //finish();
        super.onDestroy();
    }

}

Service Class:

public class DUBAudioService extends Service implements OnPreparedListener, OnCompletionListener{

Toast loadingMessage;

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

    public boolean isRunning;

    //to keep track of the playlist item
    Vector<PlaylistFile> playlistItems;

    MediaPlayer mediaPlayer;

    String baseURL = "";

    //keep track of which item from the vector we are on
    int currentPlaylistltemNumber = 0;

    public class DUBBackgroundAudioServiceBinder extends Binder {
        DUBAudioService getService() {
        return DUBAudioService.this;
        }
    }

    private final IBinder basBinderDUB = new DUBBackgroundAudioServiceBinder();



    @Override
    public IBinder onBind(Intent intent) {
        return basBinderDUB;
    }

    @Override
    public void onCreate() {
        Log.v("PLAYERSERVICE", "onCreate");
        mediaPlayer = new MediaPlayer();
        new MusicAsync().execute();
            Log.d(TAG, "execute'd async");
        mediaPlayer.setOnPreparedListener(this);
            Log.d(TAG, "set on prepared listener");
        mediaPlayer.setOnCompletionListener(this);
            Log.d(TAG, "set on completion listener");
    }

    @Override
    public int onStartCommand(Intent intent, int flags, int startId) {
        //if (!mediaPlayer.isPlaying()) {
        //  mediaPlayer.start();
        //}
        return START_STICKY;
    }

    class MusicAsync extends AsyncTask<Void,Void,Void>{
        @Override
        protected void onPreExecute(){
        }
        @Override
        protected Void doInBackground(Void... arg0) {
            // TODO Auto-generated method stub

            //create empty vector 
            playlistItems = new Vector<PlaylistFile>();

            //HTTP client library
            HttpClient httpClient = new DefaultHttpClient();
            HttpGet getRequest = new HttpGet ("http://dl.dropbox.com/u/245开发者_运维百科35120/m3u%20playlist/DubstepPlaylist.m3u"); //i think you could add the m3u thing in here 

            Log.v("URI",getRequest.getURI().toString());

            try {
            HttpResponse httpResponse = httpClient.execute(getRequest);
            if (httpResponse.getStatusLine().getStatusCode() != HttpStatus.SC_OK) {
            // ERROR MESSAGE
            Log.v("HTTP ERROR",httpResponse.getStatusLine().getReasonPhrase());
            }
            else {
                InputStream inputStream = httpResponse.getEntity().getContent(); 
                BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(inputStream));

                String line;
                while ((line = bufferedReader.readLine()) != null) { 
                    Log.v("PLAYLISTLINE","ORIG: " + line);

                    if (line.startsWith("#")) {
                        //Metadata
                        //Could do more with this but not fo now
                    } else if (line.length() > 0) {
                        String filePath = "";
                            if (line.startsWith("http://")) {
                            // Assume its a full URL 
                                filePath = line;
                            } else {
                            //Assume it’s relative
                            filePath = getRequest.getURI().resolve(line).toString();
                            }

                            PlaylistFile playlistFile = new PlaylistFile(filePath);
                            playlistItems.add (playlistFile);
                            }
                            }
                            inputStream.close();
                            }
                            } catch (ClientProtocolException e) { 
                                e.printStackTrace();
                            } catch (IOException e) {
                            e. printStackTrace();
                            }


                            currentPlaylistltemNumber = 0;
                            if (playlistItems.size() > 0)
                            {
                            String path = ((PlaylistFile)playlistItems.get(currentPlaylistltemNumber)).getFilePath();
                            try {
                                mediaPlayer.setDataSource(path);

                            mediaPlayer.prepareAsync();}
                            catch (IllegalArgumentException e) 
                            { e.printStackTrace();
                            }catch (IllegalStateException e) { 
                                e.printStackTrace();
                            }catch (IOException e) {
                            e.printStackTrace();}
                            }



            return null;
        }
        //
        protected void onPostExecute(Void result){
            //playButton. setEnabled (false);
        }
    }



    @Override
    public void onStart(Intent intent, int startId) {
        // TODO Auto-generated method stub

        super.onStart(intent, startId);
    }

    public void onDestroy() {
        if (mediaPlayer.isPlaying()) {
            mediaPlayer.stop();
            Log.d(TAG, "music stopp'd");
        }
        //mediaPlayer.release();
        Log.d(TAG, "onDestroy");
    }

    @Override
    public void onPrepared(MediaPlayer mediaPlayer) {
        // TODO Auto-generated method stub\
        Log.d(TAG, "music is prepared and will start");
        mediaPlayer.start();
    }

    public void onCompletion(MediaPlayer _mediaPlayer) {
        Log.d(TAG, "Song completed, next song");
        mediaPlayer.stop();
        mediaPlayer.reset();
            if (playlistItems.size() > currentPlaylistltemNumber + 1) { 
                currentPlaylistltemNumber++;
            String path =
                ((PlaylistFile)playlistItems.get(currentPlaylistltemNumber)).getFilePath();
                try {
                    mediaPlayer.setDataSource(path);
                    mediaPlayer.prepareAsync();
                } catch (IllegalArgumentException e) { 
                    e. printStackTrace();
                } catch (IllegalStateException e) { 
                    e.printStackTrace();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }   
    }

    class PlaylistFile {
        String filePath;
            public PlaylistFile(String _filePath) {
                filePath = _filePath;
            }
            public void setFilePath(String _filePath) {
                filePath = _filePath;
            }
            public String getFilePath() {
                return filePath;
            }
        }


    public void playSong(){
        Log.d(TAG, "start'd");
        mediaPlayer.start();
    }

    public void pauseSong(){
        Log.d(TAG, "pause'd");
        mediaPlayer.pause();
    }



}

I'd say you got lucky that it stopped -- only onPause() is guaranteed to be called when your Activity is backgrounded. The only time onDestroy() is called is when the system decides to reclaim the memory your app is using

The only guaranteed lifecycle calls are: