获取网络数据

新闻数据加载与更新机制

最新推荐文章于 2018-11-12 09:00:40 发布

原创最新推荐文章于 2018-11-12 09:00:40 发布 · 234 阅读

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CC 4.0 BY-SA版权

本文介绍了一种通过异步线程请求网络数据并解析JSON格式的新闻列表，然后使用Handler更新UI显示新闻数据的方法。具体步骤包括创建HTTP连接、发送GET请求、获取响应并转换为List对象，最后通过自定义适配器展示到ListView中。

private Handler handler = new Handler(){
    @Override
    public void handleMessage(Message msg) {
        List<RequestData.NewslistBean> newslist= (List<RequestData.NewslistBean>) msg.obj;
        MyAdapter adapter = new MyAdapter(newslist,getActivity());
        lv.setAdapter(adapter);
    }

};

private void requestNewData() {

    new Thread(){
        @Override
        public void run() {
            requestData();
        }
    }.start();

}

private void requestData() {

    try {
        URL url = new URL(urlpath);
        HttpURLConnection urlConnection = (HttpURLConnection) url.openConnection();
        urlConnection.setRequestMethod("GET");
        urlConnection.setConnectTimeout(5000);
        urlConnection.setReadTimeout(5000);
        int responseCode = urlConnection.getResponseCode();
        if (responseCode==200){
            InputStream inputStream = urlConnection.getInputStream();
            String json = toJson(inputStream);
            Gson gson = new Gson();
            RequestData requestData = gson.fromJson(json, RequestData.class);
            List<RequestData.NewslistBean> newslist = requestData.getNewslist();
            Message message = Message.obtain();
            message.obj=newslist;
            handler.sendMessage(message);

        }
    } catch (Exception e) {
        e.printStackTrace();
    }

}

private String toJson(InputStream inputStream) {
    StringBuilder builder = new StringBuilder();
    String string;
    InputStreamReader in = new InputStreamReader(inputStream);
    BufferedReader reader = new BufferedReader(in);
    try {
        while ((string=reader.readLine())!=null){
            builder.append(string);
        }
    } catch (Exception e) {
        e.printStackTrace();
    }
    return builder.toString();
}