ExpandableListView in Fragment Issue

Question

I am trying to implement an Expandable listView in a fragment. There are no errors coming and when I try to log the output from both the List<String> and HashMap<String, List<String>>, I get the actual data logged.

The issue I am getting is when I show the actual Expandable Listview in the fragment. Only the first item of the list is being shown and I cannot expand it (as per screenshot below):

.

This is the code I am using:

Fragment class

public static class LineupFragment extends Fragment {

    ExpandableListAdapter listAdapter;
    ExpandableListView expListView;
    List<String> listDataHeader;
    HashMap<String, List<String>> listDataChild;

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {

        View rootView = inflater.inflate(R.layout.fragment_lineup, null);

        expListView = (ExpandableListView) rootView.findViewById(R.id.expListView);

        prepareListData();

        listAdapter = new ExpandableListAdapter(getActivity(), listDataHeader, listDataChild);
        expListView.setAdapter(listAdapter);

        Log.i("groups", listDataHeader.toString());
        Log.i("details", listDataChild.toString());

        // Listview Group click listener
        expListView.setOnGroupClickListener(new OnGroupClickListener() {

            @Override
            public boolean onGroupClick(ExpandableListView parent, View v,int groupPosition, long id) {
                // Toast.makeText(getApplicationContext(),
                // "Group Clicked " + listDataHeader.get(groupPosition),
                // Toast.LENGTH_SHORT).show();
                return false;
            }
        });

        // Listview Group expanded listener
        expListView.setOnGroupExpandListener(new OnGroupExpandListener() {

            @Override
            public void onGroupExpand(int groupPosition) {
                Toast.makeText(getActivity().getApplicationContext(),listDataHeader.get(groupPosition) + " Expanded",Toast.LENGTH_SHORT).show();
            }
        });

        // Listview Group collasped listener
        expListView.setOnGroupCollapseListener(new OnGroupCollapseListener() {

            @Override
            public void onGroupCollapse(int groupPosition) {
                Toast.makeText(getActivity().getApplicationContext(),listDataHeader.get(groupPosition) + " Collapsed",Toast.LENGTH_SHORT).show();
            }
        });

        // Listview on child click listener
        expListView.setOnChildClickListener(new OnChildClickListener() {

            @Override
            public boolean onChildClick(ExpandableListView parent, View v,
                    int groupPosition, int childPosition, long id) {
                Toast.makeText(getActivity().getApplicationContext(),listDataHeader.get(groupPosition) + " : " + listDataChild.get(listDataHeader.get(groupPosition)).get(childPosition), Toast.LENGTH_SHORT).show();
                return false;
            }
        });   
    return rootView;
    }

    private void prepareListData() {
        listDataHeader = new ArrayList<String>();
        listDataChild = new HashMap<String, List<String>>();

        // Adding child data
        listDataHeader.add("Top 250");
        listDataHeader.add("Now Showing");
        listDataHeader.add("Coming Soon..");

        // Adding child data
        List<String> top250 = new ArrayList<String>();
        top250.add("The Shawshank Redemption");
        top250.add("The Godfather");
        top250.add("The Godfather: Part II");
        top250.add("Pulp Fiction");
        top250.add("The Good, the Bad and the Ugly");
        top250.add("The Dark Knight");
        top250.add("12 Angry Men");

        List<String> nowShowing = new ArrayList<String>();
        nowShowing.add("The Conjuring Despicable Me TurboGrown Ups 2 Red 2 the Wolverine The Conjuring Despicable Me TurboGrown Ups 2 Red 2 the Wolverine");

        List<String> comingSoon = new ArrayList<String>();
        comingSoon.add("2 Guns");
        comingSoon.add("The Smurfs 2");
        comingSoon.add("The Spectacular Now");
        comingSoon.add("The Canyons");
        comingSoon.add("Europa Report");

        listDataChild.put(listDataHeader.get(0), top250); // Header, Child data
        listDataChild.put(listDataHeader.get(1), nowShowing);
        listDataChild.put(listDataHeader.get(2), comingSoon);

    }

**Adapter class**

    public class ExpandableListAdapter extends BaseExpandableListAdapter {

                private Activity _context;
                private List<String> _listDataHeader; // header titles
                // child data in format of header title, child title
                private HashMap<String, List<String>> _listDataChild;

                public ExpandableListAdapter(Activity context, List<String> listDataHeader,
                        HashMap<String, List<String>> listChildData) {
                    this._context = context;
                    this._listDataHeader = listDataHeader;
                    this._listDataChild = listChildData;
                }

                @Override
                public Object getChild(int groupPosition, int childPosititon) {
                    return this._listDataChild.get(this._listDataHeader.get(groupPosition))
                            .get(childPosititon);
                }

                @Override
                public long getChildId(int groupPosition, int childPosition) {
                    return childPosition;
                }

                @Override
                public View getChildView(int groupPosition, final int childPosition,
                        boolean isLastChild, View convertView, ViewGroup parent) {

                    final String childText = (String) getChild(groupPosition, childPosition);

                    if (convertView == null) {
                        LayoutInflater infalInflater = (LayoutInflater) this._context
                                .getSystemService(Context.LAYOUT_INFLATER_SERVICE);
                        convertView = infalInflater.inflate(R.layout.list_item, null);
                    }

                    TextView txtListChild = (TextView) convertView.findViewById(R.id.lblListItem);

                    txtListChild.setText(childText);
                    return convertView;
                }

                @Override
                public int getChildrenCount(int groupPosition) {
                    return this._listDataChild.get(this._listDataHeader.get(groupPosition))
                            .size();
                }

                @Override
                public Object getGroup(int groupPosition) {
                    return this._listDataHeader.get(groupPosition);
                }

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

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

                @Override
                public View getGroupView(int groupPosition, boolean isExpanded,
                        View convertView, ViewGroup parent) {
                    String headerTitle = (String) getGroup(groupPosition);
                    if (convertView == null) {
                        LayoutInflater infalInflater = (LayoutInflater) this._context
                                .getSystemService(Context.LAYOUT_INFLATER_SERVICE);
                        convertView = infalInflater.inflate(R.layout.list_group, null);
                    }

                    TextView lblListHeader = (TextView) convertView.findViewById(R.id.lblListHeader);
                    lblListHeader.setTypeface(null, Typeface.BOLD);
                    lblListHeader.setText(headerTitle);

                    return convertView;
                }

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

                @Override
                public boolean isChildSelectable(int groupPosition, int childPosition) {
                    return true;
                }
            }
        }

Edit: This is the code for the fragment_lineup.xml file:

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/LinearLayout2"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="@drawable/bg_black"
    android:orientation="vertical" >

    <ExpandableListView
        android:id="@+id/expListView"
        android:layout_width="match_parent"
        android:layout_height="310dp"
        android:layout_weight="0.14" >
    </ExpandableListView>

</LinearLayout>

Then I have two other lavout files for a custom layout.

One for the **list_group.xml**:

    <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:background="@drawable/bg_black"
    android:orientation="horizontal" >

    <LinearLayout
        android:layout_width="52dp"
        android:layout_height="52dp"
        android:orientation="vertical" >

        <ImageView
            android:id="@+id/photo"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:contentDescription="@string/app_name"
            android:fitsSystemWindows="true" />

    </LinearLayout>

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="52dp"
        android:orientation="vertical" >

        <TextView
            android:id="@+id/lblListHeader"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:gravity="center_vertical"
            android:paddingLeft="6dip"
            android:paddingTop="6dip"
            android:textColor="#CC0000"
            android:textSize="20dp"
            android:textStyle="bold"
            tools:ignore="SpUsage" />

    </LinearLayout>

</LinearLayout>

And the other for the **list_item.xml**:

   <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="120dp"
    android:orientation="vertical" >

    <TextView
        android:id="@+id/lblListItem"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:background="@color/white"
        android:paddingBottom="5dp"
        android:paddingLeft="?android:attr/expandableListPreferredChildPaddingLeft"
        android:paddingTop="5dp"
        android:textSize="13sp" />

</LinearLayout>

Kindly note that I need to use a fragment because this class is part of a larger app which I am developing, and uses tabs. The whole code works fine in an activity.

I am suspecting that my issue is in the adapter class.

Answer 1

I have finally found out how this can be made. I am pasting the code below for anyone who has been encountering the same problem. Feel free to use:

public static class LineupFragment extends Fragment {

View rootView;
ExpandableListView lv;
private String[] groups;
private String[][] children;


public LineupFragment() {

}

public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    groups = new String[] { "Test Header 1", "Test Header 2", "Test Header 3", "Test Header 4" };

    children = new String [][] {
        { "s simply dummy text of the printing and typesetting industry. Lorem Ipsum has been the industry's standard dummy text ever since the 1500s, when an unknown printer took a galley of type and scrambled it to make a type specimen book. It has survived not only five centuries, but also the leap into electronic typesetting, remaining essentially unchanged. It was popularised in the 1960s with the release of Letraset sheets containing Lorem Ipsum passages, and more recently with desktop publishing software like Aldus PageMaker including versions of Lorem Ipsum." },
        { "Contrary to popular belief, Lorem Ipsum is not simply random text. It has roots in a piece of classical Latin literature from 45 BC, making it over 2000 years old. Richard McClintock, a Latin professor at Hampden-Sydney College in Virginia, looked up one of the more obscure Latin words, consectetur, from a Lorem Ipsum passage, and going through the cites of the word in classical literature, discovered the undoubtable source. Lorem Ipsum comes from sections 1.10.32 and 1.10.33 of comes from a line in section 1.10.32." },
        { "It is a long established fact that a reader will be distracted by the readable content of a page when looking at its layout. The point of using Lorem Ipsum is that it has a more-or-less normal distribution of letters, as opposed to using 'Content here, content here', making it look like readable English. Many desktop publishing packages and web page editors now use Lorem Ipsum as their default model text, and a search for 'lorem ipsum' will uncover many web sites still in their infancy. Various versions have evolved over the years, sometimes by accident, sometimes on purpose (injected humour and the like)." },
        { "There are many variations of passages of Lorem Ipsum available, but the majority have suffered alteration in some form, by injected humour, or randomised words which don't look even slightly believable. If you are going to use a passage of Lorem Ipsum, you need to be sure there isn't anything embarrassing hidden in the middle of text. All the Lorem Ipsum generators on the Internet tend to repeat predefined chunks as necessary, making this the first true generator on the Internet. It uses a dictionary of over 200 Latin words, combined with a handful of model sentence structures, to generate Lorem Ipsum which looks reasonable. The generated Lorem Ipsum is therefore always free from repetition, injected humour, or non-characteristic words etc." }
    };
}

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
    rootView = inflater.inflate(R.layout.fragment_lineup, container, false);  

return rootView;
}

@Override
public void onViewCreated(View view, Bundle savedInstanceState) {
    super.onViewCreated(view, savedInstanceState);

    lv = (ExpandableListView) view.findViewById(R.id.expListView);
    lv.setAdapter(new ExpandableListAdapter(groups, children));
    lv.setGroupIndicator(null);

}

public class ExpandableListAdapter extends BaseExpandableListAdapter {

    private final LayoutInflater inf;
    private String[] groups;
    private String[][] children;

    public ExpandableListAdapter(String[] groups, String[][] children) {
        this.groups = groups;
        this.children = children;
        inf = LayoutInflater.from(getActivity());
    }

    @Override
    public int getGroupCount() {
        return groups.length;
    }

    @Override
    public int getChildrenCount(int groupPosition) {
        return children[groupPosition].length;
    }

    @Override
    public Object getGroup(int groupPosition) {
        return groups[groupPosition];
    }

    @Override
    public Object getChild(int groupPosition, int childPosition) {
        return children[groupPosition][childPosition];
    }

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

    @Override
    public long getChildId(int groupPosition, int childPosition) {
        return childPosition;
    }

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

    @Override
    public View getChildView(int groupPosition, final int childPosition, boolean isLastChild, View convertView, ViewGroup parent) {

         ViewHolder holder;
            if (convertView == null) {
                convertView = inf.inflate(R.layout.list_item, parent, false);
                holder = new ViewHolder();

                holder.text = (TextView) convertView.findViewById(R.id.lblListItem);
                convertView.setTag(holder);
            } else {
                holder = (ViewHolder) convertView.getTag();
            }

            holder.text.setText(getChild(groupPosition, childPosition).toString());

            return convertView;
    }

    @Override
    public View getGroupView(int groupPosition, boolean isExpanded, View convertView, ViewGroup parent) {
        ViewHolder holder;

        if (convertView == null) {
            convertView = inf.inflate(R.layout.list_group, parent, false);

            holder = new ViewHolder();
            holder.text = (TextView) convertView.findViewById(R.id.lblListHeader);
            convertView.setTag(holder);
        } else {
            holder = (ViewHolder) convertView.getTag();
        }

        holder.text.setText(getGroup(groupPosition).toString());

        return convertView;
    }

    @Override
    public boolean isChildSelectable(int groupPosition, int childPosition) {
        return true;
    }

    private class ViewHolder {
        TextView text;
    }
}

And this is how the new layout now looks:

Feel free to use this in your code and hope I have helped you somehow :)