Question

How to load file from URL on every 2s (over and over )? Do I need to close connection or to stay connected ( I load one time with this code ) ? Do I need to use synchronized somewhere ?

public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);
    TextView txt=(TextView)this.findViewById(R.id.lbl);
    try {

            URL url = new URL("http://10.0.2.2/test/dynamic/test.json");
            URLConnection urlconnection = url.openConnection();
            long l = urlconnection.getContentLength();

            BufferedReader in = new BufferedReader(new InputStreamReader(url.openStream()));
            String line;
            StringBuffer buffer=new StringBuffer();
            while ((line = in.readLine()) != null)
            {
               buffer.append(line);
            }
            in.close();
            System.out.println("bufer="+buffer.toString());
            txt.setText(buffer.toString());
            Object obj = JSONValue.parse(buffer.toString());
            JSONArray array = (JSONArray) obj;


            for(Object o:array){
                JSONObject element_json = (JSONObject)o;

                int id=Integer.parseInt(""+element_json.get("id"));
                int type=Integer.parseInt(""+element_json.get("type"));
                int device_type=Integer.parseInt(""+element_json.get("device_type"));

            }

        } catch (Exception exc) {

           exc.printStackTrace();

        }  
}

Answer 1

You should be using an AsyncTask. The way you’re doing it you’re gonna get the “Application Is Not Responding” error because you’re blocking the UI thread. Any long-running operations (e.g. getting something from the cloud) should be done in the background. Once your asynctask completes, you can schedule another run in the onPostExecute method.

Also, I would recommend using RoboAsyncTask from the RoboGuice library, since it provides a much more developer (and newbie) friendly version of AsyncTask.