我已经在这里停留了一段时间。我正在使用异步任务来检索事件列表，并将它们添加到片段内的列表视图中。但是，它不会显示。有人可以告诉我怎么了吗？这将是一个很大的帮助。
以下是片段的代码：
public static class EventsSectionFragment extends Fragment {
/**
* The fragment argument representing the section number for this
* fragment.
*/
public static final String ARG_SECTION_NUMBER = "section_number";
SharedPreferences settings = null;
Editor editor;
ListView list;
TextView noEventsTv;
public EventsSectionFragment() {
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState)
{
recLifeCycle_with_savedInstanceState(savedInstanceState);
View rootView = inflater.inflate(R.layout.fragment_events, container, false);
list = (ListView) rootView.findViewById(R.id.list);
noEventsTv = (TextView) rootView.findViewById(R.id.norecordsTV);
new GetEventsAsyncTask((MainActivity) getActivity()).execute();
settings = PreferenceManager.getDefaultSharedPreferences(getActivity());
return rootView;
}
public void updateEventList(final List<Event> eventList)
{
Log.i("updateEventList:eventlist.count", String.valueOf(eventList.size()));
if (eventList.size() > 0)
{
Log.i("CustomList", "Start customlist inflation");
CustomList adapter = new CustomList(getActivity(), eventList);
noEventsTv.setVisibility(View.GONE);
list.setVisibility(View.VISIBLE);
list.setAdapter(adapter);
list.setOnItemClickListener(new AdapterView.OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> parent, View view,
int position, long id) {
String eventSel = eventList.get(position).getEvent_id();
event_id = eventSel;
// direct to event details fragment
startEventDetailsFragment();
}
});
adapter.notifyDataSetChanged();
list.invalidateViews();
}
else
{
noEventsTv.setVisibility(View.VISIBLE);
list.setVisibility(View.GONE);
}
}
这是检索事件的异步任务：
public class GetEventsAsyncTask extends AsyncTask<Void, Integer, Boolean>{
ProgressDialog progressDialog;
MainActivity activityMain;
Boolean ticketValid=false;
List<Event> eventList = new ArrayList<Event>();
public GetEventsAsyncTask(MainActivity parent)
{
activityMain = parent;
}
@Override
protected void onPreExecute() {
progressDialog = null;
if (progressDialog == null)
{
progressDialog = new ProgressDialog(activityMain);
progressDialog.setMessage("download events, please wait...");
progressDialog.show();
progressDialog.setCanceledOnTouchOutside(false);
progressDialog.setCancelable(false);
}
}
@Override
protected Boolean doInBackground(Void... params) {
// TODO Auto-generated method stub
Boolean error = false;
try {
error = postData();
} catch (JSONException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return error;
}
protected void onPostExecute(Boolean error){
/* if (progressDialog.isShowing()) {
progressDialog.dismiss();
progressDialog = null;
} */
if(error==true)
{
Log.i("GetEvents", "Error at get events");
activityMain.errorOccured();
}
else
{
Log.i("onPostExecute:eventlist.count",String.valueOf(eventList.size()));
MainActivity.myDB.removeAllEvents();
for(int i=0;i<eventList.size();i++)
{
MainActivity.myDB.insertEventEntry(eventList.get(i));
}
activityMain.downloadEventsSuccess(eventList);
}
}
protected void onProgressUpdate(Integer... progress){
}
public Boolean postData() throws JSONException {
Boolean error = false;
HttpClient httpclient = new DefaultHttpClient();
// specify the URL you want to post to
try {
HttpGet httpget = new HttpGet(Constants.HOST_NAME+"/"+Constants.SERVICE_NAME+"/api/event?userId=S6871919D");
BufferedReader reader;
StringBuffer sb;
String line = "";
String NL="";
String json;
HttpResponse response = httpclient.execute(httpget);
if(response.getStatusLine().getStatusCode()==200)
{
reader = new BufferedReader(new InputStreamReader(response.getEntity().getContent(), "UTF-8"));
sb = new StringBuffer("");
line = "";
NL = System.getProperty("line.separator");
while ((line = reader.readLine()) != null)
{
sb.append(line + NL);
}
reader.close();
json = sb.toString();
Log.i("event json",json);
try
{
JSONArray jsonArray = new JSONArray(json);
for (int i = 0, length = jsonArray.length(); i < length; i++)
{
JSONObject attribute = jsonArray.getJSONObject(i);
Event eventObj = new Event();
eventObj.setEvent_id(attribute.getString("event_id"));
eventObj.setEvent_title(attribute.getString("event_title"));
eventObj.setEvent_desc(attribute.getString("event_desc"));
eventObj.setStart_date(attribute.getString("start_date"));
eventObj.setEnd_date(attribute.getString("end_date"));
eventObj.setStart_time(attribute.getString("start_time"));
eventObj.setEnd_time(attribute.getString("end_time"));
eventObj.setLocation(attribute.getString("location"));
eventObj.setPicture_path(attribute.getString("picture_path"));
eventObj.setSmall_picture_path(attribute.getString("small_picture_path"));
eventList.add(eventObj);
eventObj = null;
}
}
catch (JSONException e)
{
e.printStackTrace();
error = true;
}
}
else
{
error = true;
}
} catch (ClientProtocolException e) {
// process execption
error = true;
} catch (IOException e) {
// process execption
error = true;
}
return error;
}
这是customList的代码：
private final Activity context;
private final List<Event> eventsList;
public CustomList(Activity context, List<Event> eventsList) {
super(context, R.layout.list_single);
this.context = context;
this.eventsList = eventsList;
}
@Override
public View getView(int position, View view, ViewGroup parent) {
//set up the inflater...
LayoutInflater inflater = context.getLayoutInflater();
View rowView= inflater.inflate(R.layout.list_single, null, true);
//reference the widgets...
TextView txtTitle = (TextView) rowView.findViewById(R.id.txt);
TextView txtDate = (TextView) rowView.findViewById(R.id.txt2);
ImageView imageView = (ImageView) rowView.findViewById(R.id.img);
Log.i("CustomList", "Start customList");
txtTitle.setText(eventsList.get(position).getEvent_title());
txtDate.setText(eventsList.get(position).getStart_date());
new GetEventsImageAsyncTask(imageView).execute(Constants.HOST_NAME + "/"+ Constants.CMS_NAME+ "/" +eventsList.get(position).getSmall_picture_path());
Log.i("CustomList", "End customList");
return rowView;
}
这是从服务器检索图像的异步任务：
public class GetEventsImageAsyncTask extends AsyncTask<String, Void, Bitmap> {
ImageView imageView;
public GetEventsImageAsyncTask(ImageView imageView){
this.imageView = imageView;
}
@Override
protected Bitmap doInBackground(String... url) {
// TODO Auto-generated method stub
String urls = url[0];
Bitmap icon = null;
try
{
InputStream input = new java.net.URL(urls).openStream();
icon = BitmapFactory.decodeStream(input);
}
catch(Exception e)
{
Log.e("GetEventImage", e.getMessage());
e.printStackTrace();
}
return icon;
}
protected void onPostExecute(Bitmap result){
imageView.setImageBitmap(result);
}
这是自定义列表的xml：
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/list_single"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="@drawable/bg"
android:orientation="horizontal">
<ImageView
android:id="@+id/img"
android:layout_width="50dp"
android:layout_height="match_parent"
android:contentDescription="@drawable/ic_launcher"/>
<TextView
android:id="@+id/txt"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_toRightOf="@+id/img"
android:text="Placeholder" />
<TextView
android:id="@+id/txt2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_toRightOf="@+id/img"
android:layout_marginTop="7dp"
android:layout_below="@+id/txt"
android:text="Placeholder" />
这是事件片段的xml：
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/fragment_events"
android:layout_width="fill_parent"
android:layout_height="fill_parent" >
<LinearLayout
android:orientation="vertical"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="@drawable/bg">
<ListView
android:id="@+id/list"
android:layout_width="fill_parent"
android:layout_height="wrap_content" >
</ListView>
<TextView
android:id="@+id/norecordsTV"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:text="@string/no_events"
android:visibility="gone"
android:gravity="center"/>
</LinearLayout>
</FrameLayout>
代码甚至不转到CustomList适配器= new CustomList（getActivity（），eventList）;我不知道为什么。正确地检索事件。
编辑：
这是logcat：
10-10 12:56:44.193: I/updateEventList:eventlist.count(16963): 4
10-10 12:56:56.473: I/MYTAG(16963): FacilitiesSectionFragment.onPause
10-10 12:56:56.473: I/MYTAG(16963): FacilitiesSectionFragment.onStop
10-10 12:56:56.473: I/MYTAG(16963): FacilitiesSectionFragment.onDestroyView
10-10 12:56:56.553: I/dalvikvm(16963): Total arena pages for JIT: 25
10-10 12:56:56.553: I/dalvikvm(16963): Total arena pages for JIT: 26
10-10 12:56:56.553: I/dalvikvm(16963): Total arena pages for JIT: 27
10-10 12:56:56.553: I/dalvikvm(16963): Total arena pages for JIT: 28
10-10 12:56:56.553: I/dalvikvm(16963): Total arena pages for JIT: 29
10-10 12:56:56.553: I/dalvikvm(16963): Total arena pages for JIT: 30
10-10 12:56:56.553: I/dalvikvm(16963): Total arena pages for JIT: 31
10-10 12:56:56.553: I/dalvikvm(16963): Total arena pages for JIT: 32
10-10 12:56:56.563: I/dalvikvm(16963): Total arena pages for JIT: 33
10-10 12:56:56.563: I/dalvikvm(16963): Total arena pages for JIT: 34
10-10 12:56:56.563: I/dalvikvm(16963): Total arena pages for JIT: 35
10-10 12:56:56.563: I/dalvikvm(16963): Total arena pages for JIT: 36
10-10 12:56:56.563: I/dalvikvm(16963): Total arena pages for JIT: 37
10-10 12:56:56.563: I/dalvikvm(16963): Total arena pages for JIT: 38
10-10 12:56:56.563: I/dalvikvm(16963): Total arena pages for JIT: 39
10-10 12:56:56.563: I/dalvikvm(16963): Total arena pages for JIT: 40
10-10 12:56:56.563: I/dalvikvm(16963): Total arena pages for JIT: 41
10-10 12:56:57.333: I/MYTAG(16963): FacilitiesSectionFragment.onCreateView / savedInstanceState == null
10-10 12:56:57.333: I/MYTAG(16963): FacilitiesSectionFragment.onStart
10-10 12:56:57.333: I/MYTAG(16963): FacilitiesSectionFragment.onResume
10-10 12:56:57.383: I/facility json(16963): [{"facility_id":"ITM00000002","facility_name":"Libary","facility_desc":"The Nanyang Polytechnic Library provides a rich and diverse collection of resources to serve the information and research needs of staff and students.","requires_booking":"N","school_code":"ARO","open_hrs":"0900","close_hrs":"2100","open_for_book":null,"picture_path":"Data/Sites/1/uploads/alumniAdmin_Facility_2014-09-22_03-51-30.png","small_picture_path":"Data/Sites/1/uploads/alumniAdmin_Facility_2014-09-22_03-30-54.png","close_from":"0001-01-01T00:00:00","close_to":"0001-01-01T00:00:00","fee":"0.00"},{"facility_id":"ITM00000004","facility_name":"Table Tennis","facility_desc":"Table Tennis for playing table tennis","requires_booking":"N","school_code":"ARO","open_hrs":"0900","close_hrs":"2100","open_for_book":null,"picture_path":"Data/Sites/1/uploads/alumniAdmin_Facility_2014-09-22_03-31-44.png","small_picture_path":"Data/Sites/1/uploads/alumniAdmin_Facility_2014-09-22_03-31-44.jpg","close_from":"0001-01-01T00:00:00","close_to":"0001-01-01T00:00:00","fee":"3.00"},{"facility_id":"ITM00000009","facility_name":"Badminton Court Pass","facility_desc":"Badminton Court Pass","requires_booking":"N","school_code":"ARO","open_hrs":"0900","close_hrs":"2100","open_for_book":null,"picture_path":"Data/Sites/1/uploads/leowzzaro_Facility_2014-10-08_11-29-05.png","small_picture_path":"Data/Sites/1/uploads/leowzzaro_Facility_2014-10-08_11-29-05.jpg","close_from":"0001-01-01T00:00:00","close_to":"0001-01-01T00:00:00","fee":"0.00"},{"facility_id":"ITM00000014","facility_name":"Badminton Court","facility_desc":"Badminton Court for playing badminton","requires_booking":"Y","school_code":"ARO","open_hrs":"0900","close_hrs":"2100","open_for_book":null,"picture_path":"Data/Sites/1/uploads/leowzzaro_Facility_2014-10-08_11-22-44.png","small_picture_path":"Data/Sites/1/uploads/leowzzaro_Facility_2014-10-08_11-22-44.jpg","close_from":"0001-01-01T00:00:00","close_to":"0001-01-01T00:00:00","fee":"3.00"}]
10-10 12:56:57.393: I/onPostExecute:facilityList.count(16963): 4
10-10 12:56:57.403: W/MY_LOG(16963): Removing Entries from facilities Success
10-10 12:56:57.403: W/MY_LOG(16963): Inserted EntryName=Libary into table facilities
10-10 12:56:57.433: W/MY_LOG(16963): Inserted EntryName=Table Tennis into table facilities
10-10 12:56:57.453: W/MY_LOG(16963): Inserted EntryName=Badminton Court Pass into table facilities
10-10 12:56:57.493: W/MY_LOG(16963): Inserted EntryName=Badminton Court into table facilities
10-10 12:56:57.513: I/updateEventList:eventlist.count(16963): 4
10-10 12:57:06.523: I/MYTAG(16963): EcardSectionFrontFragment.onPause
10-10 12:57:06.523: I/MYTAG(16963): EcardSectionFrontFragment.onStop
10-10 12:57:06.533: I/MYTAG(16963): EcardSectionFrontFragment.onDestroyView
10-10 12:57:06.533: I/MYTAG(16963): TicketSectionFragment.onCreateView / savedInstanceState == null
10-10 12:57:06.543: I/MYTAG(16963): TicketSectionFragment.onStart
10-10 12:57:06.543: I/MYTAG(16963): TicketSectionFragment.onResume
10-10 12:57:14.203: I/MYTAG(16963): EcardSectionFrontFragment.onCreateView / savedInstanceState == null
10-10 12:57:14.203: I/MYTAG(16963): TicketSectionFragment.onPause
10-10 12:57:14.203: I/MYTAG(16963): TicketSectionFragment.onStop
10-10 12:57:14.203: I/MYTAG(16963): TicketSectionFragment.onDestroyView
10-10 12:57:14.203: I/MYTAG(16963): EcardSectionFrontFragment.onStart
10-10 12:57:14.203: I/MYTAG(16963): EcardSectionFrontFragment.onResume
最佳答案
您的CustomList适配器没有列表计数，因此通过添加以下方法可以解决此问题。
@Override public int getCount()
{
if (List.size() <= 0)
{
return 0;
}
return List.size();
}
@Override
public Event getItem(int position)
{
return List.get(position);
}
@Override
public long getItemId(int position)
{
return position;
}