Change expandable indicator in ExpandableListView

Question

Trying to create an ExpandableListView. The initial view with the groups shows up fine. However, when I click the list item, my arrow does not change. See the images below.<

Answer 1

import java.util.ArrayList;

import android.app.Activity;
import android.content.Context;
import android.database.DataSetObserver;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.View.OnClickListener;
import android.view.ViewGroup;
import android.widget.BaseExpandableListAdapter;
import android.widget.ExpandableListView;
import android.widget.TextView;

public class MyActivity extends Activity {

    private ExpandableListView mExpandableList;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_my);


        mExpandableList = (ExpandableListView)findViewById(R.id.expandable_list);
        mExpandableList.setGroupIndicator(null);
        ArrayList arrayParents = new ArrayList();
        ArrayList arrayChildren = new ArrayList();

        //here we set the parents and the children
        for (int i = 0; i < 10; i++){
            //for each "i" create a new Parent object to set the title and the children
            Parent parent = new Parent();
            parent.setTitle("Parent " + i);

            arrayChildren = new ArrayList();
            for (int j = 0; j < 10; j++) {
                arrayChildren.add("Child " + j);
            }
            parent.setArrayChildren(arrayChildren);

            //in this array we add the Parent object. We will use the arrayParents at the setAdapter
            arrayParents.add(parent);
        }

        //sets the adapter that provides data to the list.
        mExpandableList.setAdapter(new MyCustomAdapter(MyActivity.this,arrayParents));

    }

    public class Parent {
        private String mTitle;
        private ArrayList mArrayChildren;

        public String getTitle() {
            return mTitle;
        }

        public void setTitle(String mTitle) {
            this.mTitle = mTitle;
        }

        public ArrayList getArrayChildren() {
            return mArrayChildren;
        }

        public void setArrayChildren(ArrayList mArrayChildren) {
            this.mArrayChildren = mArrayChildren;
        }
    }




    public class MyCustomAdapter extends BaseExpandableListAdapter implements OnClickListener{


        private LayoutInflater inflater;
        private ArrayList mParent;

        public MyCustomAdapter(Context context, ArrayList parent){
            mParent = parent;
            inflater = LayoutInflater.from(context);
        }


        @Override
        //counts the number of group/parent items so the list knows how many times calls getGroupView() method
        public int getGroupCount() {
            return mParent.size();
        }

        @Override
        //counts the number of children items so the list knows how many times calls getChildView() method
        public int getChildrenCount(int i) {
            return mParent.get(i).getArrayChildren().size();
        }

        @Override
        //gets the title of each parent/group
        public Object getGroup(int i) {
            return mParent.get(i).getTitle();
        }

        @Override
        //gets the name of each item
        public Object getChild(int i, int i1) {
            return mParent.get(i).getArrayChildren().get(i1);
        }

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

        @Override
        public long getChildId(int i, int i1) {
            return i1;
        }

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

        @Override
        //in this method you must set the text to see the parent/group on the list
        public View getGroupView(int i, boolean b, View view, ViewGroup viewGroup) {

            if (view == null) {
                view = inflater.inflate(R.layout.list_item_parent, viewGroup,false);
            }
            view.findViewById(R.id.button).setTag(i);
            view.findViewById(R.id.button).setOnClickListener(this);
            TextView textView = (TextView) view.findViewById(R.id.list_item_text_view);
            //"i" is the position of the parent/group in the list
            textView.setText(getGroup(i).toString());

            //return the entire view
            return view;
        }

        @Override
        //in this method you must set the text to see the children on the list
        public View getChildView(int i, int i1, boolean b, View view, ViewGroup viewGroup) {
            if (view == null) {
                view = inflater.inflate(R.layout.list_item_child, viewGroup,false);
            }

            TextView textView = (TextView) view.findViewById(R.id.list_item_text_child);
            //"i" is the position of the parent/group in the list and
            //"i1" is the position of the child
            textView.setText(mParent.get(i).getArrayChildren().get(i1));

            //return the entire view
            return view;
        }

        @Override
        public boolean isChildSelectable(int i, int i1) {
            return true;
        }

        @Override
        public void registerDataSetObserver(DataSetObserver observer) {
            /* used to make the notifyDataSetChanged() method work */
            super.registerDataSetObserver(observer);
        }


        /* (non-Javadoc)
         * @see android.view.View.OnClickListener#onClick(android.view.View)
         * @since Mar 20, 2013
         * @author rajeshcp 
         */
        @Override
        public void onClick(View v) {
            if(mExpandableList.isGroupExpanded((Integer)v.getTag()))
        {
            mExpandableList.collapseGroup((Integer)v.getTag());
        }else
        {
            mExpandableList.expandGroup((Integer)v.getTag());
        }
        }
    }


}

Change your MyActivity like this and let me know what else you want ?