代码：

WXMusicObject muObj = new WXMusicObject();
muObj.musicUrl  = "http://music.baidu.com/song/546920050?pst=sug";
WXMediaMessage msg = new WXMediaMessage();
msg.mediaObject = muObj;
msg.title = "越过山丘";
msg.description = "演唱：123456";
Bitmap thumBitmap = BitmapFactory.decodeResource(getResources(), android.R.drawable.ic_input_add);
msg.thumbData = bitmapToByteArray(thumBitmap, true);
SendMessageToWX.Req req = new SendMessageToWX.Req();
req.transaction = buildTransction("music");
req.message = msg;
req.scene = send_friend.isChecked() ? SendMessageToWX.Req.WXSceneTimeline : SendMessageToWX.Req.WXSceneSession;
api.sendReq(req);