Android Custom expandeablelistivew without xml layout

I am following below code to create expandablistView in android withour xml layout.its working fine,but I don't know how I can change an image If I use an image in child/group layout ? I already done code to adding the ImageView on childes/group views but how I can refresh/change the image posted using ImageView on child/group view . . Thanks in advance for guide

public class GundamExpAdapter extends BaseExpandableListAdapter { /-------------------------- Fields --------------------------/

private final HashMap<String, ArrayList<String>> myData = new HashMap<String, ArrayList<String>>();
private final HashMap<Integer, String> lookUp = new HashMap<Integer, String>();
private final Context context;



/*-------------------------- Public --------------------------*/

public GundamExpAdapter(final Context con)
{
    context = con;
}

public boolean AddGroup(final String groupName, final ArrayList<String> list)
{
    final ArrayList<String> prev = myData.put(groupName, list);

    if (prev != null)
        return false;

    lookUp.put(myData.size() - 1, groupName);

    notifyDataSetChanged();
    return true;
}

@Override
public Object getChild(int groupPos, int childPos) 
{
    if (lookUp.containsKey(groupPos))
    {
        final String str = lookUp.get(groupPos);
        final ArrayList<String> data = myData.get(str);

        return data.get(childPos);
    }

    return null;
}

@Override
public long getChildId(int groupPos, int childPos) 
{  
    return 0;
}

@Override
public View getChildView(int groupPos, int childPos, boolean isLastChild, 
                         View convertView, ViewGroup parent) 
{
    LinearLayout linear = new LinearLayout(context);

    final LayoutParams params = new LayoutParams(LayoutParams.FILL_PARENT, LayoutParams.WRAP_CONTENT);

    TextView text = new TextView(context);

    // Indent
    final String str = "\t\t\t" + (String)getChild(groupPos, childPos);

    linear = new LinearLayout(context);
    linear.setOrientation(LinearLayout.VERTICAL);

    text.setLayoutParams(params);
    text.setText(str);
    linear.addView(text);

    return linear;
}

@Override
public int getChildrenCount(int groupPos) 
{
    if (lookUp.containsKey(groupPos))
        return myData.get(lookUp.get(groupPos)).size();

    return 0;
}

@Override
public Object getGroup(int groupPos) 
{
    if (lookUp.containsKey(groupPos))
        return myData.get(lookUp.get(groupPos));

    return null;
}

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

@Override
public long getGroupId(int groupPos) 
{
    return 0;
}

@Override
public View getGroupView(int groupPos, boolean isExpanded, View convertView, ViewGroup parent) 
{
    LinearLayout linear = new LinearLayout(context);

    final LayoutParams params = new LayoutParams(LayoutParams.FILL_PARENT, LayoutParams.WRAP_CONTENT);

    TextView text = new TextView(contex开发者_C百科t);

    // Push the group name slightly to the right for drop down icon
    final String str = "\t\t" + lookUp.get(groupPos);

    linear = new LinearLayout(context);
    linear.setOrientation(LinearLayout.VERTICAL);

    text.setLayoutParams(params);
    text.setText(str);
    text.setTextSize(18.0f);
    linear.addView(text);

    return linear;
}

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

@Override
public boolean isChildSelectable(int groupPos, int childPos) 
{
    return false;
}

} And its activity as below

public class Main extends ExpandableListActivity
{
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) 
    {
        super.onCreate(savedInstanceState);
        //setContentView(R.layout.main);

        GundamExpAdapter gea = new GundamExpAdapter(this);

        ArrayList<String> models = new ArrayList<String>();
        models.add("NZ 666 Kshatriya");
        models.add("Unicorn");
        models.add("Sinanju");
        gea.AddGroup("Unicorn", models);

        models = new ArrayList<String>();
        models.add("DeathScythe");
        models.add("Altron");
        models.add("HeavyArms");
        models.add("SandRock");
        models.add("Epyon");
        models.add("ZERO");
        gea.AddGroup("Wing", models);

        setListAdapter(gea);
        ExpandableListView elv = getExpandableListView();
        elv.setTextFilterEnabled(true);
        //listview.setOnItemClickListener(OnClickingListItem());
    }
}

First you will need to change your data in order to know which row will have a different picture. Then you can call BaseExpandableListAdapter.notifyDataSetChanged() which will have the effect of calling getChildView again on each row. Then you will be able to setBackgroundDrawable() on each image view you want to change the image.