从GCM Broadcast Receiver更新列表视图

Question

我有一个自定义arrayadapter类，它有3个textviews：请求标题，日期和最新消息。我在我的主要活动中调用该类，并从位于手机内存中的文本文件中读取。当我从服务器收到消息时，如何将最新消息更改为服务器而不是文本文件？

我的主要活动

listView = (ListView)findViewById(R.id.lv_requests);

    ra = new RequestAdapter(getApplicationContext(),R.layout.request_adapter);
    listView.setAdapter(ra);

    Date date = new Date();


    if(fileExists("requests")==true){
        try{

            BufferedReader inputReader = new BufferedReader(new InputStreamReader(openFileInput("requests")));
            String in = null;
            while((in=inputReader.readLine())!=null){
                //localbroadcast manager update here

                String[] split = in.split(Pattern.quote("|"));
                String requestTitle = split[0];
                String requestDate = split[2];
                String latestMessage = split[3];
                String registrationID = split[1];
                String audioPath = split[4];
                String fileTitle = split[5];
                String textPath = "";
                Date convDate = convert(requestDate);
                Request newRequest = new Request(requestTitle,registrationID,convDate,latestMessage, audioPath,textPath,fileTitle);
                userReqs.add(newRequest);
                ra.add(newRequest);

            }

        }catch (IOException e){
            e.toString();
        }

同一活动的广播接收器

private BroadcastReceiver onNotice = new BroadcastReceiver() {
    @Override
    public void onReceive(Context context, Intent intent) {
            String str = intent.getStringExtra("msg");
            String requestTitle = intent.getStringExtra("requestTitle");
            String latestMessage = intent.getStringExtra("latestMsg");

    }
};

我是否重写文件中的行并刷新列表？