设置异步任务以将Json加载到列表视图中

AsyncTask的onPreExecute和onPostExecute将在UI线程中运行，doInBackground将在另一个线程中运行，因此下面的代码对您来说很合适

public class YourActivity extends Activiy{   public void getJson(String selection, String url) { new LoadJsonTask().execute( selection, url);   }   private class LoadJsonTask extends AsyncTask<String, Void, ArrayList<HashMap<String, String>> > {       ProgressDialog dialog ;       protected void onPreExecute (){ dialog = ProgressDialog.show(YourActivity.this ,"title","message");       }       protected ArrayList<HashMap<String, String>> doInBackground (String... params){return doGetJson(params[0],params[1]);       }       protected void onPostExecute(ArrayList<HashMap<String, String>> mylist){ ListAdapter adapter = new JsonAdapter(YourActivity.this, mylist, R.layout.list,   new String[] { "name", "text", "ts"}, new int[] { R.id.item_title,     R.id.item_subtitle, R.id.timestamp}); setListAdapter(adapter); dialog.dismiss();       }    } public ArrayList<HashMap<String, String>> doGetJson(String selection, String url) {     JSonObject json = null;     String formatedcat = selection.toLowerCase();     ArrayList<HashMap<String, String>> mylist = new ArrayList<HashMap<String, String>>();     json = JSonfunctions        .getJSonfromURL(url);     try {    //the array title that you parse    JSonArray category = json.getJSonArray(formatedcat);    for (int i = 0; i < category.length(); i++) { HashMap<String, String> map = new HashMap<String, String>();        JSonObject c = category.getJSonObject(i);        map.put("id", String.valueOf(i));        map.put("name",     c.getString("title"));        //map.put("text",c.getString("title"));        map.put("ts",c.getString("run_date") );        map.put("image","http:"+c.getString("url"));        mylist.add(map);    }} catch (JSonException e) {}   return mylist;  ....   }