它表明问题出在这里:
@Override
public int getChildrenCount(int groupPosition) {
return hashMap.get(groupPosition).size();
}
我尝试打印地图大小,但确实如此。它只有两个键:“即将发生的事件”和“过去的事件”。我使用containsKey()进行了检查,结果为true。但是我仍然无法以某种方式获取List对象的大小。
这可能有助于了解我没有为此创建另一个类文件,并且所有代码都捆绑在同一个类文件中。
这是我的代码:
class CustomEventListAdapter extends BaseExpandableListAdapter{
HashMap<String, List<Event>> hashMap;
Context con;
CustomEventListAdapter(Context context, HashMap<String, List<Event>> map){
hashMap = map;
con = context;
}
List<String> groupTitle = Arrays.asList("Upcoming Events","Past Events");
@Override
public int getGroupCount() {
return groupTitle.size();
}
@Override
public int getChildrenCount(int groupPosition) {
return hashMap.get(groupPosition).size();
}
@Override
public Object getGroup(int groupPosition) {
return groupTitle.get(groupPosition);
}
@Override
public Object getChild(int groupPosition, int childPosition) {
return hashMap.get(groupTitle.get(groupPosition)).get(childPosition);
}
@Override
public long getGroupId(int groupPosition) {
return groupPosition;
}
@Override
public long getChildId(int groupPosition, int childPosition) {
return childPosition;
}
@Override
public boolean hasStableIds() {
return false;
}
@Override
public View getGroupView(int groupPosition, boolean isExpanded, View convertView, ViewGroup parent) {
if (convertView == null) {
LayoutInflater layoutInflater = (LayoutInflater) getApplicationContext()
.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
convertView = layoutInflater.inflate(R.layout.expandable_list_group, null);
}
TextView listTitleTextView = (TextView) convertView
.findViewById(R.id.groupHeader);
listTitleTextView.setTypeface(null, Typeface.BOLD);
listTitleTextView.setText(groupTitle.get(groupPosition));
return convertView; }
@Override
public View getChildView(int groupPosition, int childPosition, boolean isLastChild, View convertView, ViewGroup parent) {
if (convertView == null) {
LayoutInflater layoutInflater = (LayoutInflater) getApplicationContext()
.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
convertView = layoutInflater.inflate(R.layout.expandable_list_item, null);
}
TextView eventName = (TextView) convertView.findViewById(R.id.eventName);
TextView eventDate = (TextView) convertView.findViewById(R.id.eventDate);
TextView eventDesc = (TextView) convertView.findViewById(R.id.eventDesc);
ImageView imageView = (ImageView) convertView.findViewById(R.id.eventPic);
eventName.setText(hashMap.get(groupPosition).get(childPosition).getName());
eventDate.setText(hashMap.get(groupPosition).get(childPosition).getDate());
eventDesc.setText(hashMap.get(groupPosition).get(childPosition).getDetails());
return convertView; }
@Override
public boolean isChildSelectable(int groupPosition, int childPosition) {
return true;
}
}
这是onCreate():
expandableListView = (ExpandableListView) findViewById(R.id.eventList);
hashMap = new HashMap<>();
FirebaseDatabase database = FirebaseDatabase.getInstance();
DatabaseReference reference = database.getReference().child("Events");
reference.addListenerForSingleValueEvent(new ValueEventListener() {
@Override
public void onDataChange(@NonNull DataSnapshot dataSnapshot) {
List<Event> eventList = new ArrayList<>();
//List<Event> upcoming = new ArrayList<>();
//List<Event> past = new ArrayList<>();
for (DataSnapshot postSnapshot : dataSnapshot.getChildren()) {
Event event = new Event();
event.name = String.valueOf(postSnapshot.child("Name").getValue());
event.details = String.valueOf(postSnapshot.child("Details").getValue());
event.add = String.valueOf(postSnapshot.child("PhotoAdd").getValue());
event.date = String.valueOf(postSnapshot.child("Date").getValue());
eventList.add(event);
Toast.makeText(EventsActivity.this, "longDate = " + event.getLongDate() , Toast.LENGTH_SHORT).show();
}
long current = Calendar.getInstance().getTimeInMillis();
Collections.sort(eventList, new Sortbyroll());
int i=0;
for( i=0; i< eventList.size(); i++){
if(eventList.get(i).getLongDate() < current){
break;
}
}
hashMap.put("Upcoming Events", eventList.subList(0,i));
hashMap.put("Past Events", eventList.subList(i,eventList.size()));
ExpandableListAdapter listAdapter = new CustomEventListAdapter(getBaseContext(),hashMap);
expandableListView.setAdapter(listAdapter);
}
@Override
public void onCancelled(@NonNull DatabaseError databaseError) {
}
});
答案 0 :(得分:0)
也许您在此处输入的代码不完整,因为我找不到“ hashMap.put(groupPosition,....)”之类的东西。 我的意思是,您试图获取该组的内容,但是没有任何代码可以对其进行设置。对于称为“即将发生的事件”和“过去的事件”的特殊组,仅调用两个“ put()”方法。.....因此,“ hashMap”只能包含这两个值。