我已经从 JSON 中获取了字符串值，但它似乎在 Hash map 或其他东西中存在问题，我在我的 List 适配器上获得了 null 值。谁能帮助我或告诉我我的代码是否做错了什么。提前致谢。这是我的代码。
活动 -
public class TestJSON extends Activity{
public static ListView lv;
public static ProgressDialog pDialog;
public static LazyAdapter adapter;
static final String KEY_ITEMS = "items";
static final String KEY_TITLE = "title";
static final String KEY_ID = "id";
@Override
protected void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
setContentView(R.layout.test_json_view);
new AsyncInitial().execute();
// Showing progress dialog before sending http request
pDialog = new ProgressDialog(this);
pDialog.setMessage("Please wait..");
pDialog.setIndeterminate(true);
pDialog.setCancelable(false);
pDialog.show();
lv = (ListView)findViewById(R.id.list);
//lv.setAdapter(new ArrayAdapter(getApplicationContext(), android.R.layout.simple_expandable_list_item_1, items));
}
private class AsyncInitial extends AsyncTask<Void, Void, ArrayList<HashMap<String, String>>> {
ArrayList<HashMap<String, String>> menuItems;
@Override
protected void onPreExecute() {
}
@Override
protected ArrayList<HashMap<String, String>> doInBackground(Void... arg0) {
menuItems = new ArrayList<HashMap<String, String>>();
try {
//if (vid_num <= 0) {
// Get a httpclient to talk to the internet
HttpClient client = new DefaultHttpClient();
// Perform a GET request to YouTube for a JSON list of all the videos by a specific user
//https://gdata.youtube.com/feeds/api/videos?author="+username+"&v=2&alt=jsonc
HttpUriRequest request = new HttpGet("http://gdata.youtube.com/feeds/api/playlists/SP86E04995E07F6BA8?v=2&start-index=1&max-results=50&alt=jsonc");
// Get the response that YouTube sends back
HttpResponse response = client.execute(request);
// Convert this response into a readable string
String jsonString = StreamUtils.convertToString(response.getEntity().getContent());
// Create a JSON object that we can use from the String
JSONObject json = new JSONObject(jsonString);
// For further information about the syntax of this request and JSON-C
// see the documentation on YouTube http://code.google.com/apis/youtube/2.0/developers_guide_jsonc.html
// Get are search result items
JSONArray jsonArray = json.getJSONObject("data").getJSONArray(KEY_ITEMS);
// Get the total number of video
//String vid_num = json.getJSONObject("data").getString("totalItems");
//System.out.println("vid_num-------->"+ vid_num);
// Loop round our JSON list of videos creating Video objects to use within our app
for (int i = 0; i < jsonArray.length(); i++) {
HashMap<String, String> map = new HashMap<String, String>();
JSONObject jsonObject = jsonArray.getJSONObject(i);
// The title of the video
String title = jsonObject.getJSONObject("video").getString(KEY_TITLE);
System.out.println("Title-------->"+ title);
// A url to the thumbnail image of the video
// We will use this later to get an image using a Custom ImageView
//String TAG_thumbUrl = jsonObject.getJSONObject("video").getJSONObject("thumbnail").getString("sqDefault");
//System.out.println("thumbUrl-------->"+ thumbUrl);
String id = jsonObject.getJSONObject("video").getString(KEY_ID);
System.out.println("video_id-------->"+ id);
map.put(title, KEY_TITLE);
map.put(id, KEY_ID);
menuItems.add(map);
}
} catch (ClientProtocolException e) {
//Log.e("Feck", e);
} catch (IOException e) {
//Log.e("Feck", e);
} catch (JSONException e) {
//Log.e("Feck", e);
}
return menuItems;
}
@Override
protected void onPostExecute(ArrayList<HashMap<String, String>> result) {
super.onPostExecute(result);
adapter = new LazyAdapter(TestJSON.this,menuItems);
lv.setAdapter(adapter);
pDialog.dismiss();
}
}
}
和适配器
public class LazyAdapter extends BaseAdapter {
private Activity activity;
private static LayoutInflater inflater;
private ArrayList<HashMap<String, String>> data;
public LazyAdapter(TestJSON testJSON, ArrayList<HashMap<String, String>> menuItems) {
activity = testJSON;
data = menuItems;
inflater = (LayoutInflater)activity.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
}
@Override
public int getCount() {
return data.size();
}
@Override
public Object getItem(int position) {
return data.get(position);
}
@Override
public long getItemId(int position) {
return position;
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
View vi=convertView;
if(convertView==null)vi = inflater.inflate(R.layout.list_row, null);
TextView title = (TextView)vi.findViewById(R.id.title);
TextView id = (TextView)vi.findViewById(R.id.artist);
HashMap<String, String> item = new HashMap<String, String>();
item = data.get(position);
title.setText(item.get(TestJSON.KEY_TITLE));
id.setText(item.get(TestJSON.KEY_ID));
return vi;
}
}