Android-恢復活動中的服務並銷燬它們銷燬

Question

我目前有一個Activty，當創建時開始並綁定service。這service有一個mediaplayer。我想要做的是如果活動是resumed然後service繼續播放等。當activity被銷燬時，它應該stopservice。到目前爲止，我可以同時獲得服務，以便在重新激活活動時繼續玩，並且在創建新活動時停止服務，但不能同時停止。任何建議或想法？謝謝。下面的代碼：

活動類：

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(); 
    } 

} 

服務類：

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/24535120/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(); 
    } 



} 

Answer 1

我說你很幸運，它停止了 - 只有onPause()保證當你的活動被稱爲中背景。唯一的一次onDestroy()被稱爲是當系統決定收回你的應用程序使用

唯一可以保證的生命週期調用內存是：只有

• onCreate()當應用程序是白手起家;
• onResume()每次運行，無論是暫停還是首次創建;
• onPause()每次系統將您的應用程序移動到背景時，週期。