在展开时更改GroupView背景（ExpandableListView）

Question

我正在搜索如何在扩展/崩溃时更改groupview的背景。我没有找到答案，但我解决了这个问题：

BaseExpandableListAdapter：

@Override
public View getGroupView(int groupPosition, boolean isExpanded, View convertView, ViewGroup parent) {
    ViewHolderGroup holder;
    if ( convertView == null ){
        convertView = inflater.inflate(R.layout.home_cell, null);
        holder = new ViewHolderGroup();
        convertView.setTag(holder);

        holder.tvNome = (TextView) convertView.findViewById(R.id.cellNome);
        holder.btCodigo = (ToggleButtonEbrimaBold) convertView.findViewById(R.id.btCodigo);
        holder.tvLancadas = (TextView) convertView.findViewById(R.id.cellLancadas);
        holder.layoutBackground = (LinearLayout) convertView.findViewById(R.id.layoutBackground);
    }
    else{
        holder = (ViewHolderGroup) convertView.getTag();
    }

    holder.layoutBackground.setSelected(isExpanded);

    return convertView;
}

ViewHolderGroup ：

class ViewHolderGroup {
    TextView tvNome;
    ToggleButtonEbrimaBold btCodigo;
    TextView tvLancadas;
    LinearLayout layoutBackground;
    LinearLayout layoutReceiver;
}

home_cell.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="match_parent"
android:layout_height="match_parent">

<LinearLayout
    android:id="@+id/layoutBackground"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:minHeight="100dp"
    android:orientation="vertical"
    android:gravity="center_vertical"
    android:background="@drawable/disciplina_line">

... GroupView content ...

</LinearLayout>
</LinearLayout>

disciplina_line.xml：

<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android">
    <item android:state_selected="false" android:drawable="@drawable/line_white"/>
    <item android:state_selected="true" android:drawable="@drawable/line_selected"/>
</selector>

我想分享这个选择。希望它有所帮助！