我有来自YouTube的JSON数据。我想在LIST VIEW中显示数据。但是当我运行我的代码时，我得到一个空白页面。但我有YouTube DATA API的回复。我该如何解决？
public class MainActivity extends ListActivity {
private ProgressDialog pDialog;
// URL to get contacts JSON
private static String url = "https://www.googleapis.com/youtube/v3/search?part=snippet&maxResult=30&q=natok+bangla+mosharrof+karim&key=AIzaSyCR40QlsuX0aFfBV-wEPDsH_jxna1tDFRA";
private static final String TAG_ITEMS = "items";
private static final String TAG_ID = "id";
private static final String TAG_ID_VIDEOID = "vid";
private static final String TAG_TITLE = "title";
private static final String TAG_DESCRIPTION = "description";
private static final String YouTubeThumbnail = "https://i.ytimg.com/vi/hlaX2OZ_kDg/default.jpg";
private static final String TAG_CHANNELTITLE = "channelTitle";
JSONArray items = null;
// Hashmap for ListView
ArrayList<HashMap<String, String>> dataList;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
dataList = new ArrayList<HashMap<String, String>>();
ListView lv = getListView();
lv.setOnItemClickListener(new AdapterView.OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> parent, View view,
int position, long id) {
// getting values from selected ListItem
String vid = ((TextView) view.findViewById(R.id.name))
.getText().toString();
String title = ((TextView) view.findViewById(R.id.email))
.getText().toString();
String description = ((TextView) view.findViewById(R.id.mobile))
.getText().toString();
// Starting single contact activity
Intent in = new Intent(getApplicationContext(),
SingleContactActivity.class);
in.putExtra(TAG_ID_VIDEOID, vid);
in.putExtra(TAG_TITLE, title);
in.putExtra(TAG_DESCRIPTION, description);
startActivity(in);
}
});
new GetContacts().execute();
}
private class GetContacts extends AsyncTask<Void, Void, Boolean> {
@Override
protected void onPreExecute() {
super.onPreExecute();
// Showing progress dialog
pDialog = new ProgressDialog(MainActivity.this);
pDialog.setMessage("Please wait...");
pDialog.setCancelable(false);
pDialog.show();
}
@Override
protected Boolean doInBackground(Void... arg0) {
// Creating service handler class instance
ServiceHandler sh = new ServiceHandler();
// Making a request to url and getting response
String jsonStr = sh.makeServiceCall(url, ServiceHandler.GET);
Log.d("Response: ", "> " + jsonStr);
ArrayList<HashMap<String, String>> dataList = new ArrayList<HashMap<String,String>>();
int count = 0;
try {
JSONObject js = new JSONObject(jsonStr);
JSONArray jsItem = js.getJSONArray("items");
for (int i = 0; i < jsItem.length(); i++) {
JSONObject item = jsItem.getJSONObject(i);
JSONObject vid =item.getJSONObject("id");
String videoId = getStringResult(vid.toString(), "videoId");
if (!videoId.equalsIgnoreCase(""))
{
JSONObject snippet =item.getJSONObject("snippet");
String title = sh.getStringResult(snippet.toString(), "title");
HashMap<String, String> map = new HashMap<String, String>();
map.put("name", title);
map.put("vid", videoId);
map.put ("img","http://img.youtube.com/vi/" + videoId + "/hqdefault.jpg");
map.put ("id",++count+"");
dataList.add(map);
}
}
} catch (JSONException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return true;
}
@Override
protected void onPostExecute(Boolean result) {
super.onPostExecute(result);
// Dismiss the progress dialog
if (pDialog.isShowing())
pDialog.dismiss();
/**
* Updating parsed JSON data into ListView
* */
ListAdapter adapter = new SimpleAdapter(
MainActivity.this, dataList,R.layout.list_item, new String[] { TAG_TITLE, TAG_DESCRIPTION,
TAG_CHANNELTITLE }, new int[] { R.id.name,
R.id.email, R.id.mobile });
setListAdapter(adapter);
}
}
public String getStringResult(String data, String node) {
try {
JSONObject js = new JSONObject(data);
return js.getString(node);
} catch (JSONException e) {
// TODO Auto-generated catch block
e.printStackTrace();
return "";
}
}
答案 0 :(得分：0)
使用notifyDataSetChanged（）。这会通知数据更改并更新列表视图。 LINK
以下是有帮助的更改：
public class MainActivity extends ListActivity {
...
ListAdapter adapter = null;
@Override
public void onCreate(Bundle savedInstanceState) {
...
ListView lv = getListView();
adapter = new SimpleAdapter(
MainActivity.this, dataList,R.layout.list_item, new String[] { TAG_TITLE, TAG_DESCRIPTION,
TAG_CHANNELTITLE }, new int[] { R.id.name,
R.id.email, R.id.mobile });
lv.setListAdapter(adapter);
...
}
private class GetContacts extends AsyncTask<Void, Void, Boolean> {
@Override
protected void onPreExecute() {
...
}
@Override
protected Boolean doInBackground(Void... arg0) {
...
}
@Override
protected void onPostExecute(Boolean result) {
if(adapter ! = null) {
adapter.notifyDataSetChanged();
}
}
public String getStringResult(String data, String node) {
...
}
说明：
有关详情，请仔细阅读link。