Android下載mp3文件並播放它

Question

我試圖從Dropbox下載一些音頻文件供用戶下次沒有互聯網時使用，所以代碼實際上下載文件，但我有麻煩播放該音頻我不知道如果我要解析下載的文件什麼的，希望你能幫助

下載文件，併發揮它的類，它發揮它在後執行，或至少它試圖

class DownloadFileFromURL extends AsyncTask<String, String, String> { 

     /** 
     * Before starting background thread Show Progress Bar Dialog 
     */ 
     @Override 
     protected void onPreExecute() { 
      super.onPreExecute(); 
      showDialog(progress_bar_type); 
     } 

     /** 
     * Downloading file in background thread 
     */ 
     @Override 
     protected String doInBackground(String... f_url) { 
      int count; 
      try { 
       URL url = new URL(f_url[0]); 
       URLConnection conection = url.openConnection(); 
       conection.connect(); 

       // this will be useful so that you can show a tipical 0-100% 
       // progress bar 
       int lenghtOfFile = conection.getContentLength(); 

       // download the file 
       InputStream input = new BufferedInputStream(url.openStream(), 
         8192); 

       // Output stream 
       OutputStream output = new FileOutputStream(Environment.getExternalStorageDirectory().getPath()+"/workout.mp3"); 

       byte data[] = new byte[1024]; 

       long total = 0; 

       while ((count = input.read(data)) != -1) { 
        total += count; 
        // publishing the progress.... 
        // After this onProgressUpdate will be called 
        publishProgress("" + (int) ((total * 100)/lenghtOfFile)); 

        // writing data to file 
        output.write(data, 0, count); 
       } 

       // flushing output 
       output.flush(); 

       // closing streams 
       output.close(); 
       input.close(); 

      } catch (Exception e) { 
       Log.e("Error: ", e.getMessage()); 
      } 
      return null; 
     } 
     /** 
     * Updating progress bar 
     */ 
     protected void onProgressUpdate(String... progress) { 
      // setting progress percentage 
      pDialog.setProgress(Integer.parseInt(progress[0])); 
     } 
     /** 
     * After completing background task Dismiss the progress dialog 
     **/ 
     @Override 
     protected void onPostExecute(String file_url) { 
      // dismiss the dialog after the file was downloaded 
      dismissDialog(progress_bar_type); 
      Uri u = Uri.parse(Environment.getExternalStorageDirectory().getPath()+"/workout.mp3"); 

      MediaPlayer mediaPlayer = new MediaPlayer(); 
      try { 
       mediaPlayer.setAudioStreamType(AudioManager.STREAM_MUSIC); 
       mediaPlayer.setDataSource(Environment.getExternalStorageDirectory().getPath()+"/workout.mp3"); 
       mediaPlayer.prepare(); 
      } catch (IOException e) { 
       e.printStackTrace(); 
      } 
      mediaPlayer.setOnPreparedListener(new MediaPlayer.OnPreparedListener() { 
       @Override 
       public void onPrepared(MediaPlayer mp) { 
        mp.start(); 
       } 
      }); 
     } 
    } 

IM實際上得到的日誌

05-31 11:46:11.605 4638-4650/com.example.project.calisthenic E/MediaPlayer: error (1, -2147483648) 

這個錯誤

問題是試圖播放下載的文件，即使嘗試播放它與Android本地播放器它說「播放器不支持這種類型的音頻文件」，所以我不知道如果我' m以錯誤的方式下載文件o嘗試以錯誤的方式播放文件。

我會檢查和文件大小爲10KB和下載後是400B所以肯定有什麼不對勁的下載

Answer 1

我不知道這個問題從它來了，但你應該準備設置在調用準備函數之前的偵聽器。