android - 无法播放音乐文件

Question

我试图让用户选择一个文件，然后再播放。

case R.id.choose_ringtone_btn:
        isPaused = true;
        Intent intent = new Intent();
        intent.setType("audio/*");
        intent.setAction(Intent.ACTION_GET_CONTENT);
        startActivityForResult(Intent.createChooser(intent, "Select Audio "), REQUEST_ID);
        break;
    }
}

@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
    super.onActivityResult(requestCode, resultCode, data);
    if (requestCode == REQUEST_ID && data != null) {
        Uri uri = data.getData();
        savefile(uri);
        editor.putString(URI_STR, uri.toString()).commit();
    }
}

void savefile(Uri sourceuri)
{
    String sourceFilename= sourceuri.getPath();
    String destinationFilename = android.os.Environment.getExternalStorageDirectory().getPath()+File.separatorChar+"abc.mp3";

    BufferedInputStream bis = null;
    BufferedOutputStream bos = null;

    try {
      bis = new BufferedInputStream(new FileInputStream(sourceFilename));
      bos = new BufferedOutputStream(new FileOutputStream(destinationFilename, false));
      byte[] buf = new byte[1024];
      bis.read(buf);
      do {
        bos.write(buf);
      } while(bis.read(buf) != -1);
    } catch (IOException e) {

    } finally {
      try {
        if (bis != null) bis.close();
        if (bos != null) bos.close();
      } catch (IOException e) {

      }
    }
}

我不能通过这个： bis = new BufferedInputStream(new FileInputStream(sourceFilename)); 这是为什么？