使用的AsyncTask来显示的ListView数据

问题描述

我需要我的一点点帮助。我需要在ListView中使用的AsyncTask 以显示数据。但我不知道该怎么becouse我是新的机器人编程......非常感谢你的帮助。

I need me a little help. I need to use asynctask to display data in ListView. But I don't know how becouse I'm new in Android programming ... thank you very much for any help.

public class Main extends ListActivity {
Button buttonbg;
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
   setContentView(R.layout.listplaceholder);

    ArrayList<HashMap<String, String>> mylist = new ArrayList<HashMap<String, String>>();

    JSONObject json = JSONfunctions.getJSONfromURL("http://10.10.10.10/data.php");

    try{

        JSONArray  ip = json.getJSONArray("ip");

        for(int i=0;i<ip.length();i++){
            HashMap<String, String> map = new HashMap<String, String>();
            JSONObject e = ip.getJSONObject(i);

            map.put("id",  String.valueOf(i));
            map.put("data1", e.getString("date"));
            map.put("data2", "Location:" +  e.getString("location") + "   Status:" + e.getString("status"));
            mylist.add(map);
        }
    }catch(JSONException e)        {
         Log.e("log_tag", "Error parsing data "+e.toString());
    }

    ListAdapter adapter = new SimpleAdapter(this, mylist , R.layout.main,
                    new String[] { "data1", "data2" },
                    new int[] { R.id.item_title, R.id.item_subtitle });

    setListAdapter(adapter);

    final ListView lv = getListView();
    lv.setTextFilterEnabled(true);

}}

推荐答案

试试这个

new MyAsyncTask.execute("http://10.10.10.10/data.php");

声明的任务，因为

Declare the task as

class MyAsyncTask extends AsyncTask<String, Integer, ArrayList<HashMap<String, String>> > {

    ArrayList<HashMap<String, String>> mylist = new ArrayList<HashMap<String, String>>();

    @Override
    protected ArrayList<HashMap<String, String>> doInBackground(String... params) {

        JSONObject json = JSONfunctions.getJSONfromURL(params[0]);

        try {
            JSONArray  ip = json.getJSONArray("ip");

            for (int i=0;i<ip.length();i++) {
                HashMap<String, String> map = new HashMap<String, String>();
                JSONObject e = ip.getJSONObject(i);

                map.put("id",  String.valueOf(i));
                map.put("data1", e.getString("date"));
                map.put("data2", "Location:" +  e.getString("location") + "   Status:" + e.getString("status"));
                mylist.add(map);
            }
            return mylist
        } catch (JSONException e) {
            Log.e("log_tag", "Error parsing data "+e.toString());
        }
        return null;
    }

    @Override
    protected void onPostExecute(ArrayList<HashMap<String, String>> result) {
        ListAdapter adapter = new SimpleAdapter(YourActivity.this, result , R.layout.main,
                new String[] { "data1", "data2" },
                new int[] { R.id.item_title, R.id.item_subtitle });
        YourActivity.this.setListAdapter(adapter); // If Activity extends ListActivity
        final ListView lv = getListView();
        lv.setTextFilterEnabled(true);

    }

希望它帮助。

Hope it helps.

这篇关于使用的AsyncTask来显示的ListView数据的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！