Question

我有用户的数据库结构，每个用户都有用户圈子。我想检索圈子名称，并使用圈子名称填充每个listview标题，并使用与每个用户相对应的用户填充可扩展的详细信息。

我实现了ExpanableListView，但我很难检索实时数据。我知道firebase ui适配器只能使用简单的列表视图，但不能扩展listview这里是我的代码到目前为止。

CustomExpandableListAdapter

public class CustomExpandableListAdapter extends BaseExpandableListAdapter {


private Context context;
private List<String> expandableListTitle;
private HashMap<String, List<String>> expandableListDetail;

public CustomExpandableListAdapter(Context context, List<String> expandableListTitle,
                                   HashMap<String, List<String>> expandableListDetail) {
    this.context = context;
    this.expandableListTitle = expandableListTitle;
    this.expandableListDetail = expandableListDetail;
}

@Override
public Object getChild(int listPosition, int expandedListPosition) {
    return this.expandableListDetail.get(this.expandableListTitle.get(listPosition))
            .get(expandedListPosition);
}

@Override
public long getChildId(int listPosition, int expandedListPosition) {
    return expandedListPosition;


}
@Override
public View getChildView(int listPosition, final int expandedListPosition,
                         boolean isLastChild, View convertView, ViewGroup parent) {
    final String expandedListText = (String) getChild(listPosition, expandedListPosition);
    if (convertView == null) {
        LayoutInflater layoutInflater = (LayoutInflater) this.context
                .getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        convertView = layoutInflater.inflate(R.layout.list_item, null);
    }
    TextView expandedListTextView = (TextView) convertView
            .findViewById(R.id.expandedListItem);
    expandedListTextView.setText(expandedListText);
    return convertView;
}

@Override
public int getChildrenCount(int listPosition) {
    return this.expandableListDetail.get(this.expandableListTitle.get(listPosition))
            .size();
}

@Override
public Object getGroup(int listPosition) {
    return this.expandableListTitle.get(listPosition);
}

@Override
public int getGroupCount() {
    return this.expandableListTitle.size();
}

@Override
public long getGroupId(int listPosition) {
    return listPosition;
}

@Override
public View getGroupView(int listPosition, boolean isExpanded,
                         View convertView, ViewGroup parent) {
    String listTitle = (String) getGroup(listPosition);
    if (convertView == null) {
        LayoutInflater layoutInflater = (LayoutInflater) this.context.
                getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        convertView = layoutInflater.inflate(R.layout.list_group, null);
    }
    TextView listTitleTextView = (TextView) convertView
            .findViewById(R.id.listTitle);
    listTitleTextView.setTypeface(null, Typeface.BOLD);
    listTitleTextView.setText(listTitle);
    return convertView;
}

@Override
public boolean hasStableIds() {
    return false;
}

@Override
public boolean isChildSelectable(int listPosition, int expandedListPosition) {
    return true;
}
}

CirclesFragment

  ExpandableListView expandableListView;
ExpandableListAdapter expandableListAdapter;
List<String> expandableListTitle;
HashMap<String, List<String>> expandableListDetail;

@Override
public void onViewCreated(View view, @Nullable Bundle savedInstanceState) {
    super.onViewCreated(view, savedInstanceState);
    auth = FirebaseAuth.getInstance();
    if (auth.getCurrentUser() == null) {
        startActivity(new Intent(getActivity(), login.class));

    } else {
       //fetch list of groups from database
        mFirebaseDatabase = FirebaseDatabase.getInstance();
        myRef=mFirebaseDatabase.getReference();

        FirebaseUser user =auth.getCurrentUser();
        userID=user.getUid();



        expandableListView = (ExpandableListView) getView().findViewById(R.id.expandableListView);


        expandableListDetail = getData(myRef,userID);

        expandableListTitle = new ArrayList<String>(expandableListDetail.keySet());

        expandableListAdapter = new CustomExpandableListAdapter(getContext(), expandableListTitle, expandableListDetail);
        expandableListView.setAdapter(expandableListAdapter);
        expandableListView.setOnGroupExpandListener(new ExpandableListView.OnGroupExpandListener() {

            @Override
            public void onGroupExpand(int groupPosition) {
                Toast.makeText(getContext(),
                        expandableListTitle.get(groupPosition) + " List Expanded.",
                        Toast.LENGTH_SHORT).show();
            }
        });

        expandableListView.setOnGroupCollapseListener(new ExpandableListView.OnGroupCollapseListener() {

            @Override
            public void onGroupCollapse(int groupPosition) {
                Toast.makeText(getContext(),
                        expandableListTitle.get(groupPosition) + " List Collapsed.",
                        Toast.LENGTH_SHORT).show();

            }
        });

        expandableListView.setOnChildClickListener(new ExpandableListView.OnChildClickListener() {
            @Override
            public boolean onChildClick(ExpandableListView parent, View v,
                                        int groupPosition, int childPosition, long id) {
                Toast.makeText(
                        getContext(),
                        expandableListTitle.get(groupPosition)
                                + " -> "
                                + expandableListDetail.get(
                                expandableListTitle.get(groupPosition)).get(
                                childPosition), Toast.LENGTH_SHORT
                ).show();
                return false;
            }
        });

加载列表（）方法

 private void loadList() {
    myRef.child("users").child(userID).child("circles").addValueEventListener(new ValueEventListener() {
        @Override
        public void onDataChange(DataSnapshot dataSnapshot) {
            lst = new ArrayList<String>(); // Result will be holded Here
            for (DataSnapshot dsp : dataSnapshot.getChildren()) {
                Log.d("bbb",String.valueOf(dsp.getKey()));
                lst.add(String.valueOf(dsp.getKey())); //add result into array list


    //need to bind the real time data in ExpandableListView somehow        


            }
        }

        @Override
        public void onCancelled(DatabaseError databaseError) {

        }
    });

}

Answer 1

我从未使用过展开式列表，但使用类似notifyDataSetChanged();之类的内容在Adapter上更新ListView。

我建议

private void loadList() {
myRef.child("users").child(userID).child("circles").addValueEventListener(new ValueEventListener() {
    @Override
    public void onDataChange(DataSnapshot dataSnapshot) {
        for (DataSnapshot dsp : dataSnapshot.getChildren()) {
            Log.d("bbb",String.valueOf(dsp.getKey()));
            expandableListTitle.add(String.valueOf(dsp.getKey())); //add result into array list
            //need to bind the real time data in ExpandableListView somehow        
         }
         expandableListAdapter.notifyDataSetChanged();
    }

    @Override
    public void onCancelled(DatabaseError databaseError) {

    }
 });
}

注意：

将您已注册的List<>数据放入Adapter课程中，而不是新ArrayList<>

来自Firebase数据库的ExpanableListView

1 个答案: