List Adapter receives the objects but it does not display them in the List View - arrays

Question

So, here is the case, in the onPostExecute method I have used a ListView and I have adapted a list adapter in it in order to display the objects (events) in a list view. The problem is that the adapter recognizes the objects but it does not display them in the ListView. I have looked of how to populate an Array of Hashmaps with a List adapter and I am prettu sure that I have done it correctly in my code. I think that the problem might be in the xml file. Any ideas that can guide me to the right direction?
This is my xml file:
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<ListView
android:id="#android:id/list"
android:layout_width="match_parent"
android:layout_height="match_parent">
</ListView>
<TextView
android:id="#+id/id"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:paddingBottom="2dip"
android:paddingTop="6dip"
android:textSize="16sp"/>
<TextView
android:id="#+id/title"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:paddingBottom="2dip" />
<TextView
android:id="#+id/date"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:gravity="start"/>
<TextView
android:id="#+id/time"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:gravity="start" />
<TextView
android:id="#+id/time_end"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:gravity="start" />
</LinearLayout>
And the .java file:
public class EventsJSONActivity extends ListActivity {
private static String url = "http://mob.students.acg.edu/json3.php";
public static final String TAG_EVENT_INFO = "eventsinfo";
public static final String TAG_ID = "id";
public static final String TAG_TITLE = "title";
public static final String TAG_DATE = "date";
public static final String TAG_TIME = "time";
public static final String TAG_TIME_END = "time_end";
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_events_json);
new GetEvents().execute();
}
class GetEvents extends AsyncTask<Void,Void,Void> {
ArrayList<HashMap<String,String>> eventList;
ProgressDialog proDialog;
#Override
protected void onPreExecute() {
super.onPreExecute();
proDialog = new ProgressDialog(EventsJSONActivity.this);
Log.d("prodialog: ","Setting Message.");
proDialog.setMessage("Please wait...");
Log.d("prodialog: ","Setting cancellable.");
proDialog.setCancelable(false);
Log.d("prodialog: ","Showing...");
proDialog.show();
}
#Override
protected Void doInBackground(Void... arg0) {
WebRequest webreq = new WebRequest();
String url = "http://mob.students.acg.edu/json3.php";
String jsonStr = webreq.makeWebServiceCall(url,WebRequest.POSTRequest);
Log.d("Response: ", "> " + jsonStr);
eventList = ParseJSON(jsonStr);
Log.d("eventList info: " , eventList.toString());
return null;
}
//!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
#Override
protected void onPostExecute(Void requestresult) {
super.onPostExecute(requestresult);
if (proDialog.isShowing()) {
proDialog.dismiss();
Log.d("prodialog: ","dismissing dialog.");
}
Log.d("Listadapter: ", "eventList: " + eventList.toString());
ListAdapter adapter = new SimpleAdapter(
EventsJSONActivity.this,eventList,
android.R.layout.simple_list_item_1,
new String[] {TAG_ID, TAG_TITLE, TAG_DATE, TAG_TIME, TAG_TIME_END},
new int[] {R.id.id,R.id.title,R.id.date,R.id.time,R.id.time_end});
Log.d("Listadapter: ","data fed");
ListView lv = (ListView)findViewById(android.R.id.list);
lv.setAdapter(adapter);
Log.d("Listadapter: ",adapter.getCount() + " items set");
}//!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
private ArrayList<HashMap<String,String>> ParseJSON(String json) {
if (json != null) {
try {
ArrayList<HashMap<String,String>> eventList = new ArrayList<>();
JSONObject jsonObj = new JSONObject(json);
JSONArray events = jsonObj.getJSONArray(TAG_EVENT_INFO);
for (int i = 0; i < events.length(); i++) {
JSONObject j = events.getJSONObject(i);
String id = j.getString(TAG_ID);
String title = j.getString(TAG_TITLE);
String date = j.getString(TAG_DATE);
String time = j.getString(TAG_TIME);
String time_end = j.getString(TAG_TIME_END);
HashMap<String,String> event = new HashMap<String,String>();
event.put(TAG_ID,id);
event.put(TAG_TITLE,title);
event.put(TAG_DATE,date);
event.put(TAG_TIME,time);
event.put(TAG_TIME_END,time_end);
/*event.put(TAG_ID,"id");
event.put(TAG_TITLE,"title");
event.put(TAG_DATE,"date");
event.put(TAG_TIME,"time");
event.put(TAG_TIME_END,"time_end");*/
eventList.add(event);
}
Log.d("EventList > ", eventList.toString());
return eventList;
} catch (JSONException e) {
e.printStackTrace();
return null;
}
} else {
Log.e("ServiceHandler", "No data received from HTTP Request");
return null;
}
}
}
}

Answer 1

Try checking the solution that was posted here ... updating ListView from AsyncTask. The runOnUiThread runnable may be what you are missing since the code you have here looks correct. If that doesn't work, you can try creating class levels variables for the listview and/or adapter and modify them in the onPostExecute of AsyncTask.
Hope this helps!