这是我创建listview的片段。当数据发生变化时，listview不会通知。我怎样才能做到这一点？我使用volley在viewModel中发出请求。我收到下一个错误：java.lang.IllegalStateException：适配器的内容已更改但ListView未收到通知。确保不从后台线程修改适配器的内容，而只是从UI线程修改。确保适配器在其内容更改时调用notifyDataSetChanged（）。 [在ListView（2131558620，类android.widget.ListView）中使用适配器（类pharma.com.pharmaapp.Common.EventsArrayAdapter）] 在android.widget.ListView.layoutChildren（ListView.java:1582）
public class EventesFragment extends Fragment {
private final String TAG = EventesFragment.class.getSimpleName();
private ArrayList<EvenimentType> events = new ArrayList<>();
private ListView eventsListView;
private SwipeRefreshLayout swipeContainer;
public EventsArrayAdapter eventsArrayAdapter;
private EventsFragmentViewModel eventsFragmentViewModel = new EventsFragmentViewModel();
@Nullable
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.fragment_events, container, false);
FloatingActionButton fab = (FloatingActionButton) view.findViewById(R.id.fab);
fab.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
Intent intent = new Intent(getActivity(), SearchActivity.class);
startActivity(intent);
}
});
if(events.size() != 0) {
events.clear();
}
eventsListView = (ListView) view.findViewById(R.id.listView_events);
swipeContainer = (SwipeRefreshLayout) view.findViewById(R.id.swipeContainer);
eventsListView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
String name = ((EvenimentType) eventsListView.getAdapter().getItem(position)).getName();
Log.d(TAG, "Click " + name);
Intent intent = new Intent(getActivity(), SelectedEventActivity.class);
intent.putExtra("Parceable", events.get(position));
startActivity(intent);
}
});
eventsListView.setOnItemLongClickListener(new AdapterView.OnItemLongClickListener() {
@Override
public boolean onItemLongClick(AdapterView<?> parent, View view, int position, long id) {
String name = ((EvenimentType) eventsListView.getAdapter().getItem(position)).getName();
return false;
}
});
swipeContainer.setOnRefreshListener(new SwipeRefreshLayout.OnRefreshListener() {
@Override
public void onRefresh() {
events.clear();
eventsFragmentViewModel.loadEvents(getActivity());
eventsFragmentViewModel.setInterface(new EventsFragmentViewModel.EventsFragmentInterface() {
@Override
public void takeData(ArrayList<EvenimentType> list) {
if(eventsArrayAdapter == null) {
eventsArrayAdapter = new EventsArrayAdapter(getActivity(), list);
eventsListView.setAdapter(eventsArrayAdapter);
swipeContainer.setRefreshing(false);
} else {
events = list;
getActivity().runOnUiThread(new Runnable() {
@Override
public void run() {
eventsArrayAdapter.notifyDataSetChanged();
}
});
swipeContainer.setRefreshing(false);
}
}
});
}
});
loadEvents();
return view;
}
public void loadElementsToArrayAdapter() {
eventsArrayAdapter = new EventsArrayAdapter(getContext(), events);
// eventsArrayAdapter.notifyDataSetChanged();
swipeContainer.setRefreshing(false);
eventsListView.setAdapter(eventsArrayAdapter);
eventsFragmentViewModel.saveEvents(events, getActivity());
}
public void loadEvents() {
eventsFragmentViewModel.loadEvents(getActivity());
eventsFragmentViewModel.setInterface(new EventsFragmentViewModel.EventsFragmentInterface() {
@Override
public void takeData(ArrayList<EvenimentType> list) {
events = list;
loadElementsToArrayAdapter();
}
});
}
@Override
public void onResume() {
super.onResume();
// eventsFragmentViewModel.getUserEventsId(getActivity());
}
}
This is the Base Adapter class:
public class EventsArrayAdapter extends BaseAdapter {
private static final String TAG = EventsArrayAdapter.class.getSimpleName();
private Context context;
private List<EvenimentType> list = null;
public EventsArrayAdapter(Context context, List<EvenimentType> objects) {
this.context = context;
this.list = objects;
}
public void addAll(List<EvenimentType> objects) {
if(list == null) {
list = new ArrayList<>();
}
list.addAll(objects);
notifyDataSetChanged();
}
@Override
public int getCount() {
return list.size();
}
@Override
public Object getItem(int position) {
return list.get(position);
}
@Override
public long getItemId(int position) {
return 0;
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
LayoutInflater inflater = (LayoutInflater) context
.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
if(convertView == null) {
convertView = inflater.inflate(R.layout.item_array_adapter, null);
}
TextView title = (TextView) convertView.findViewById(R.id.text_simposion_title);
TextView date = (TextView) convertView.findViewById(R.id.text_simposion_date);
TextView location = (TextView) convertView.findViewById(R.id.text_simposion_location);
TextView price = (TextView) convertView.findViewById(R.id.text_simposion_price);
ImageView image = (ImageView) convertView.findViewById(R.id.image_event);
Log.d(TAG, "Checking: " + checkEvent(list.get(position)));
if (checkSelection(list.get(position)) == true) {
title.setText(list.get(position).getName());
date.setText(list.get(position).getDate());
location.setText(list.get(position).getLocation());
price.setText(list.get(position).getPaid());
image.setImageResource(R.drawable.ic_simposions);
} else {
title.setText(list.get(position).getName());
date.setText(list.get(position).getDate());
location.setText(list.get(position).getLocation());
price.setText(list.get(position).getPaid());
}
Log.d(TAG, "getView");
return convertView;
}
This is the viewModel where I make the request
public class EventsFragmentViewModel extends LoginViewModel {
private static final String TAG = EventsFragmentViewModel.class.getSimpleName();
private ArrayList<EvenimentType> events = new ArrayList<>();
EventsFragmentInterface listener = null;
public void loadEvents(final Context context) {
DataServices dataServices = new DataServices(context);
dataServices.getEvents();
dataServices.setCommunicationInterface(new RequestToServer.CommunicationInterface() {
@Override
public void takeResponse(JSONObject response) {
try {
Log.d(TAG, response.toString());
EvenimentType evenimentType = new EvenimentType();
JSONArray obj = response.getJSONArray("entry");
Log.d(TAG, obj.length() + "");
for (int i = 0; i < obj.length(); i++) {
events.add(evenimentType.createEvent(obj.getJSONObject(i)));
}
} catch (JSONException e) {
e.printStackTrace();
}
Log.d(TAG, "EVENTS: " + events.size());
if(listener!= null) {
listener.takeData(events);
}
}
});
}
public void saveEvents(ArrayList<EvenimentType> list, Context context) {
Preferences preferences = new Preferences(context);
preferences.saveToSharedPreferencesEvents(list);
preferences.getFromSharedPreferencesEvents();
}
public void setInterface(EventsFragmentInterface listener) {
this.listener = listener;
}
public interface EventsFragmentInterface {
public void takeData(ArrayList<EvenimentType> list);
}
}