我在android中工作。在我的项目中有一个JSON解析字段，我实现了AsyncTask，但我的代码中出现以下错误。谁能解决这个问题并帮助我完成我的项目。
以下是我的课......
import java.util.ArrayList;
import java.util.HashMap;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
import android.app.ListActivity;
import android.app.ProgressDialog;
import android.content.Intent;
import android.os.AsyncTask;
import android.os.Bundle;
import android.view.View;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.ListAdapter;
import android.widget.ListView;
import android.widget.SimpleAdapter;
public class MyListActivity extends ListActivity {
// url to make request
private static String url = "https://maps.googleapis.com/maps/api/place/textsearch/json?query=restaurants+in+Sydney&sensor=true&key=AIzaSyD38pak_katUfSR92WE2_O2b9y0JSp5htA";
// JSON Node names
private static final String TAG_CONTACTS = "results";
private static final String TAG_ID = "id";
private static final String TAG_NAME = "name";
private static final String TAG_ADDRESS = "formatted_address";
private static final String TAG_GENDER = "rating";
// contacts JSONArray
JSONArray contacts = null;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
new LoadData().execute();
}
class LoadData extends AsyncTask<String, String, String>
{
// Hashmap for ListView
ArrayList<HashMap<String, String>> contactList = new ArrayList<HashMap<String, String>>();
protected String doInBackground(String... args) {
MyListActivity pl1 = new MyListActivity();
// Creating JSON Parser instance
JSONParser jParser = new JSONParser();
// getting JSON string from URL
JSONObject json = jParser.getJSONFromUrl(url);
try {
// Getting Array of Contacts
contacts = json.getJSONArray(TAG_CONTACTS);
// looping through All Contacts
for(int i = 0; i < contacts.length(); i++){
JSONObject c = contacts.getJSONObject(i);
// Storing each json item in variable
String id = c.getString(TAG_ID);
String name = c.getString(TAG_NAME);
// String email = c.getString(TAG_EMAIL);
String formatted_address = c.getString(TAG_ADDRESS);
String rating = c.getString(TAG_GENDER);
// Phone number is agin JSON Object
// JSONObject phone = c.getJSONObject(TAG_PHONE);
// String mobile = phone.getString(TAG_PHONE_MOBILE);
// String home = phone.getString(TAG_PHONE_HOME);
// String office = phone.getString(TAG_PHONE_OFFICE);
// creating new HashMap
HashMap<String, String> map = new HashMap<String, String>();
// adding each child node to HashMap key => value
map.put(TAG_ID, id);
map.put(TAG_NAME, name);
map.put(TAG_ADDRESS, formatted_address);
map.put(TAG_GENDER, rating);
// map.put(TAG_EMAIL, email);
// map.put(TAG_PHONE_MOBILE, mobile);
// adding HashList to ArrayList
contactList.add(map);
}
} catch (JSONException e) {
e.printStackTrace();
}
return null;
}
protected void onPostExecute(String file_url) {
/**
* Updating parsed JSON data into ListView
* */
ListAdapter adapter = new SimpleAdapter(this, contactList,
R.layout.listview_item_row,
new String[] { TAG_NAME, TAG_ADDRESS, TAG_GENDER,}, new int[] {
R.id.txtTitle, R.id.txtTitle1, R.id.txtTitle3 });
setListAdapter(adapter);
// selecting single ListView item
ListView lv = getListView();
// Launching new screen on Selecting Single ListItem
lv.setOnItemClickListener(new OnItemClickListener() {
public void onItemClick(AdapterView<?> parent, View view,
int position, long id) {
// getting values from selected ListItem
// String name = ((TextView) view.findViewById(R.id.name)).getText().toString();
// String cost = ((TextView) view.findViewById(R.id.formatted_address)).getText().toString();
// String description = ((TextView) view.findViewById(R.id.mobile)).getText().toString();
// Starting new intent
Intent in = new Intent(getApplicationContext(), ProfileViewActivity.class);
// in.putExtra(TAG_NAME, name);
// in.putExtra(TAG_EMAIL, cost);
// in.putExtra(TAG_PHONE_MOBILE, description);
startActivity(in);
}
});
}
}
}