android - Android : 展開可能なリストを裏返しに理解する

Question

私はAndroidの初心者です。カスタム アダプターを使用した Expandable ListView の実装を理解したい。このコードを操作できるように、誰かこのコードを説明してください。変数「groupStatus」が配列変数として使用される理由など、特定の質問を念頭に置いています。展開可能なリストの子ノードにテキストビューを配置することはできません。よろしくお願いします。

public class ExpandableListAdapter extends BaseExpandableListAdapter {

private Context mContext;
private ExpandableListView mExpandableListView;
private List<GroupEntity> mGroupCollection;
private int[] groupStatus;

public ExpandableListAdapter(Context pContext, ExpandableListView pExpandableListView, List<GroupEntity> pGroupCollection) {
 mContext = pContext;
 mGroupCollection = pGroupCollection;
 mExpandableListView = pExpandableListView;
 groupStatus = new int[mGroupCollection.size()];

setListEvent();
 }

private void setListEvent() {

mExpandableListView.setOnGroupExpandListener(new OnGroupExpandListener() {

@Override
 public void onGroupExpand(int arg0) {
 // TODO Auto-generated method stub
 groupStatus[arg0] = 1;
 }
 });

mExpandableListView.setOnGroupCollapseListener(new OnGroupCollapseListener() {

@Override
 public void onGroupCollapse(int arg0) {
 // TODO Auto-generated method stub
 groupStatus[arg0] = 0;
 }
});
}

@Override
public String getChild(int arg0, int arg1) {
// TODO Auto-generated method stub
return mGroupCollection.get(arg0).GroupItemCollection.get(arg1).Name;
}

@Override
 public long getChildId(int arg0, int arg1) {
 // TODO Auto-generated method stub
 return 0;
 }

@Override
 public View getChildView(int arg0, int arg1, boolean arg2, View arg3,
 ViewGroup arg4) {
 // TODO Auto-generated method stub

ChildHolder childHolder;
 if (arg3 == null) {
 arg3 = LayoutInflater.from(mContext).inflate(
 R.layout.list_group_item, null);

childHolder = new ChildHolder();

childHolder.title = (TextView) arg3.findViewById(R.id.item_title);
arg3.setTag(childHolder);
 }else {
 childHolder = (ChildHolder) arg3.getTag();
 }

   childHolder.title.setText(mGroupCollection.get(arg0).GroupItemCollection.get(arg1).Name);

 return arg3;
 }

@Override
 public int getChildrenCount(int arg0) {
 // TODO Auto-generated method stub
 return mGroupCollection.get(arg0).GroupItemCollection.size();
 }

@Override
 public Object getGroup(int arg0) {
 // TODO Auto-generated method stub
 return mGroupCollection.get(arg0);
}

@Override
 public int getGroupCount() {
  // TODO Auto-generated method stub
 return mGroupCollection.size();
 }

@Override
 public long getGroupId(int arg0) {
// TODO Auto-generated method stub
 return arg0;
 }

@Override
 public View getGroupView(int arg0, boolean arg1, View arg2, ViewGroup arg3) {
 // TODO Auto-generated method stub
 GroupHolder groupHolder;
 if (arg2 == null) {
arg2 = LayoutInflater.from(mContext).inflate(R.layout.list_group,
 null);
groupHolder = new GroupHolder();
groupHolder.img = (ImageView) arg2.findViewById(R.id.tag_img);
groupHolder.title = (TextView) arg2.findViewById(R.id.group_title);
 arg2.setTag(groupHolder);
} else {
groupHolder = (GroupHolder) arg2.getTag();
}
if (groupStatus[arg0] == 0) {
groupHolder.img.setImageResource(R.drawable.group_down);
} else {
groupHolder.img.setImageResource(R.drawable.group_up);
}
groupHolder.title.setText(mGroupCollection.get(arg0).Name);

return arg2;
}

class GroupHolder {
 ImageView img;
 TextView title;
 }

class ChildHolder {
 TextView title;
 }

@Override
public boolean hasStableIds() {
// TODO Auto-generated method stub
return true;
}

@Override
public boolean isChildSelectable(int arg0, int arg1) {
// TODO Auto-generated method stub
return true;
}

}