expandablelistview with custom arraylist dosen't show childlist

Question

I'm writing an application with an expandablelistview an a custom arrayList. My problem is that the expandablelistview doesn't show me the child items and I don't know where is the problem. The arrayList is coming from a class that I create for save same data in a database.

I post the code below:

public class CustomAdapterExpandable extends BaseExpandableListAdapter {

    private Context c;
    private ArrayList<Data> data;
    private FireBaseReadData fireBaseReadData;
    private DatabaseReference databaseReference;
    private Preference preference = new Preference();

    public CustomAdapterExpandable(Context ctx, ArrayList<Data> data) {
        this.c = ctx;
        this.data = data;
    }




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

    @Override
    public int getChildrenCount(int groupPosition) {
        data.get(0).get(groupPosition);
        return data.size();

    }

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

    @Override
    public Object getChild(int groupPosition, int childPosition) {
        return data.get(groupPosition).get(childPosition);
    }

    @Override
    public long getGroupId(int groupPosition) {
        return data.get(0).get(groupPosition);
    }

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

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

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

        databaseReference = FirebaseDatabase.getInstance().getReference();
        fireBaseReadData = new FireBaseReadData(databaseReference);
        if(convertView == null){
            convertView = LayoutInflater.from(c).inflate(R.layout.mainlayout, parent, false);
        }

        TextView name = (TextView) convertView.findViewById(R.id.TxT_text);
        Button Btn_Reg = (Button) convertView.findViewById(R.id.Btn_ShowDialog);
        final Data data = (Data) this.getGroup(groupPosition);
        name.setText(data.getTournamentName());
        Btn_Reg.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                ShowDialog(groupPosition);
            }
        });



        return convertView;
    }

    @Override
    public View getChildView(int groupPosition, int childPosition, boolean isLastChild, View convertView, ViewGroup parent) {
        final Data data = (Data) this.getChild(groupPosition, childPosition);
        if(convertView == null){
            convertView = LayoutInflater.from(c).inflate(R.layout.childlayout, parent, false);
        }

        TextView register = (TextView) convertView.findViewById(R.id.txt_reg);
        TextView players = (TextView) convertView.findViewById(R.id.txt_players);
        register.setText(data.getNumberOfPlayer());
        players.setText(data.getNumberOfPlayer());

        return convertView;
    }

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

}

Data class

public class Data {

    String tournamentName;
    String nameCreator;
    int numberOfPlayer;
    int playerAvailable;
    String name_Player;

    Data(){

    }

    /***********************************************/
    private int getPlayerAvailable() {
        return playerAvailable;
    }

    void setPlayerAvailable(int PlayerAvailable) {
        playerAvailable = PlayerAvailable;
    }
    /***********************************************/
    public int getNumberOfPlayer() {
        return numberOfPlayer;
    }

    void setNumberOfPlayer(int numbPlayer) {
        numberOfPlayer = numbPlayer;
    }
    /***********************************************/
    public String getName_Player() {
        return name_Player;
    }

    void setName_Player(String name_player) {
        name_Player = name_player;
    }
    /***********************************************/
    String getTournamentName() {
        return tournamentName;
    }

    void setTournamentName(String NameTournament) {
        tournamentName = NameTournament;
    }
    /***********************************************/
    String getNameCreator() {
        return nameCreator;
    }

    void setNameCreator(String Name) {
        nameCreator = Name;
    }


    int get(int n){
        return n;
    }
}

Thanks for answers.

Answer 1

you are not getting child size properly try this

@Override
public int getChildrenCount(int groupPosition) {
   return groupList.get(groupPosition).getChild().size();
}

Group Class

public class Group {

String groupName;
int groupID;
ArrayList<Data>child=new ArrayList<Data>();
public String getGroupName() {
    return groupName;
}

public void setGroupName(String groupName) {
    this.groupName = groupName;
}

public int getGroupID() {
    return groupID;
}

public void setGroupID(int groupID) {
    this.groupID = groupID;
}

public ArrayList<Data> getChild() {
    return child;
}

public void setChild(ArrayList<Data> child) {
    this.child = child;
}
}

then pass ArrayList Of Groups to your adapter