问如何用JSON & AsyncTask动态显示LISTVIEW？

EN

public class MainActivity extends Activity {
// Declare Variables
JSONObject jsonobject;
JSONArray jsonarray;
ListView listview;
ListViewAdapter adapter;
ProgressDialog mProgressDialog;
ArrayList<HashMap<String, String>> arraylist;
static String url = "https://www.googleapis.com/youtube/v3/search?part=snippet&maxResult=30&q=natok+bangla+mosharrof+karim&key=AIzaSyCR40QlsuX0aFfBV-wEPDsH_jxna1tDFRA";

static String VIDEO_ID = "videoId";
static String TITLE = "title";
static String DESCRIPTION = "description";
//static String FLAG = "flag";

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    // Get the view from listview_main.xml
    setContentView(R.layout.listview_main);
    // Execute DownloadJSON AsyncTask
    new DownloadJSON().execute();
}

// DownloadJSON AsyncTask
private class DownloadJSON extends AsyncTask<Void, Void, Void> {

    @Override
    protected void onPreExecute() {
        super.onPreExecute();
        // Create a progressdialog
        mProgressDialog = new ProgressDialog(MainActivity.this);
        // Set progressdialog title
        mProgressDialog.setTitle("Android JSON Parse Tutorial");
        // Set progressdialog message
        mProgressDialog.setMessage("Loading...");
        mProgressDialog.setIndeterminate(false);
        // Show progressdialog
        mProgressDialog.show();
    }

    @Override
    protected Void doInBackground(Void... params) {
        // Create an array
        arraylist = new ArrayList<HashMap<String, String>>();
        // Retrieve JSON Objects from the given URL address
        jsonobject = JSONfunctions
                .getJSONfromURL("https://www.googleapis.com/youtube/v3/search?part=snippet&maxResult=30&q=natok+bangla&key=AIzaSyCR40QlsuX0aFfBV-wEPDsH_jxna1tDFRA");

        try {
            // Locate the array name in JSON
            jsonarray = jsonobject.getJSONArray("items");

            for (int i = 0; i < jsonarray.length(); i++) {
                HashMap<String, String> map = new HashMap<String, String>();
                jsonobject = jsonarray.getJSONObject(i);
                // Retrive JSON Objects
                map.put("videoId", jsonobject.getString("videoId"));
                map.put("title", jsonobject.getString("title"));
                map.put("description", jsonobject.getString("description"));
               // map.put("flag", jsonobject.getString("flag"));
                // Set the JSON Objects into the array
                arraylist.add(map);
            }
        } catch (JSONException e) {
            Log.e("Error", e.getMessage());
            e.printStackTrace();
        }
        return null;
    }

    @Override
    protected void onPostExecute(Void args) {
        // Locate the listview in listview_main.xml
        listview = (ListView) findViewById(R.id.listview);
        // Pass the results into ListViewAdapter.java
        adapter = new ListViewAdapter(MainActivity.this, arraylist);
        // Set the adapter to the ListView
        listview.setAdapter(adapter);
        // Close the progressdialog
        mProgressDialog.dismiss();
    }
}

public class ListViewAdapter extends BaseAdapter {

// Declare Variables
Context context;
LayoutInflater inflater;
ArrayList<HashMap<String, String>> data;
ImageLoader imageLoader;
HashMap<String, String> resultp = new HashMap<String, String>();

public ListViewAdapter(Context context,
                       ArrayList<HashMap<String, String>> arraylist) {
    this.context = context;
    data = arraylist;
    imageLoader = new ImageLoader(context);
}

@Override
public int getCount() {
    return data.size();
}

@Override
public Object getItem(int position) {
    return null;
}

@Override
public long getItemId(int position) {
    return 0;
}

public View getView(final int position, View convertView, ViewGroup parent) {
    // Declare Variables
    TextView rank;
    TextView country;
    TextView population;
    ImageView flag;

    inflater = (LayoutInflater) context
            .getSystemService(Context.LAYOUT_INFLATER_SERVICE);

    View itemView = inflater.inflate(R.layout.listview_item, parent, false);
    // Get the position
    resultp = data.get(position);

    // Locate the TextViews in listview_item.xml
    rank = (TextView) itemView.findViewById(R.id.rank);
    country = (TextView) itemView.findViewById(R.id.country);
    population = (TextView) itemView.findViewById(R.id.population);

    // Locate the ImageView in listview_item.xml
    flag = (ImageView) itemView.findViewById(R.id.flag);

    // Capture position and set results to the TextViews
    rank.setText(resultp.get(MainActivity.VIDEO_ID));
    country.setText(resultp.get(MainActivity.TITLE));
    population.setText(resultp.get(MainActivity.DESCRIPTION));
    // Capture position and set results to the ImageView
    // Passes flag images URL into ImageLoader.class
  //  imageLoader.DisplayImage(resultp.get(MainActivity.FLAG), flag);
    // Capture ListView item click
    itemView.setOnClickListener(new OnClickListener() {

        @Override
        public void onClick(View arg0) {
            // Get the position
            resultp = data.get(position);
            Intent intent = new Intent(context, SingleItemView.class);
            // Pass all data rank
            intent.putExtra("videoId", resultp.get(MainActivity.VIDEO_ID));
            // Pass all data country
            intent.putExtra("title", resultp.get(MainActivity.TITLE));
            // Pass all data population
            intent.putExtra("description",resultp.get(MainActivity.DESCRIPTION));
            // Pass all data flag
        //    intent.putExtra("flag", resultp.get(MainActivity.FLAG));
            // Start SingleItemView Class
            context.startActivity(intent);

        }
    });
    return itemView;
}

public class JSONfunctions {

public static JSONObject getJSONfromURL(String url) {
    InputStream is = null;
    String result = "";
    JSONObject jArray = null;

    // Download JSON data from URL
    try {
        HttpClient httpclient = new DefaultHttpClient();
        HttpPost httppost = new HttpPost(url);
        HttpResponse response = httpclient.execute(httppost);
        HttpEntity entity = response.getEntity();
        is = entity.getContent();

    } catch (Exception e) {
        Log.e("log_tag", "Error in http connection " + e.toString());
    }

    // Convert response to string
    try {
        BufferedReader reader = new BufferedReader(new InputStreamReader(
                is, "iso-8859-1"), 8);
        StringBuilder sb = new StringBuilder();
        String line = null;
        while ((line = reader.readLine()) != null) {
            sb.append(line + "\n");
        }
        is.close();
        result = sb.toString();
    } catch (Exception e) {
        Log.e("log_tag", "Error converting result " + e.toString());
    }

    try {

        jArray = new JSONObject(result);
    } catch (JSONException e) {
        Log.e("log_tag", "Error parsing data " + e.toString());
    }

    return jArray;
}

<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />

<application
    android:icon="@mipmap/ic_launcher"
    android:label="@string/app_name"
    android:theme="@style/AppTheme" >
    <activity android:name=".MainActivity" >
        <intent-filter>
            <action android:name="android.intent.action.MAIN" />

            <category android:name="android.intent.category.LAUNCHER" />
        </intent-filter>
    </activity>
    <activity android:name=".SingleItemView" >
    </activity>
</application>