Android学习笔记-ExpandableListView的使用

Android中listview只能将item逐行显示，不能实现树形效果，ExpandableListView是对listView的扩充，可以显示 类似QQ列表的效果，ExpandableListView只支持二级列表。ExpandableListView的使用与ListView类似。下面是我写的小例子
首先继承BaseExpandableListAdapter

public class MyAdapter extends BaseExpandableListAdapter {    private List<List<Map<String,String>>> group;    Context context;    public MyAdapter(List<List<Map<String,String>>> data,Context context){        this.group=data;        this.context=context;    }//返回组的数量    @Override    public int getGroupCount() {        return group.size();    }//返回组内的children数量    @Override    public int getChildrenCount(int groupPosition) {        return group.get(groupPosition).size();    }    @Override    public Object getGroup(int groupPosition) {        return group.get(groupPosition);    }    @Override    public Object getChild(int groupPosition, int childPosition) {        return group.get(groupPosition).get(childPosition);    }    @Override    public long getGroupId(int groupPosition) {        return groupPosition;    }    @Override    public long getChildId(int groupPosition, int childPosition) {        return childPosition;    }    @Override    public boolean hasStableIds() {        return false;    }//对一级目录进行填充    @Override    public View getGroupView(int groupPosition, boolean isExpanded, View convertView, ViewGroup parent) {        ViewHolder viewHolder;        if(convertView==null){            convertView=LayoutInflater.from(context).inflate(R.layout.group_view,null);            viewHolder=new ViewHolder();            viewHolder.imageView=(ImageView)convertView.findViewById(R.id.g_image);            viewHolder.textView=(TextView)convertView.findViewById(R.id.g_text);            convertView.setTag(viewHolder);        }        else{            viewHolder=(ViewHolder)convertView.getTag();        }        viewHolder.imageView.setImageResource(R.mipmap.ic_launcher);        viewHolder.textView.setText("group");        return convertView;    }//填充子目录    @Override    public View getChildView(int groupPosition, int childPosition, boolean isLastChild, View convertView, ViewGroup parent) {        ViewHolder viewHolder;        if(convertView==null){            convertView=LayoutInflater.from(context).inflate(R.layout.group_view,null);            viewHolder=new ViewHolder();            viewHolder.imageView=(ImageView)convertView.findViewById(R.id.g_image);            viewHolder.textView=(TextView)convertView.findViewById(R.id.g_text);            convertView.setTag(viewHolder);        }        else{            viewHolder=(ViewHolder)convertView.getTag();        }        viewHolder.imageView.setImageResource(R.mipmap.ic_launcher);        viewHolder.textView.setText(group.get(groupPosition).get(childPosition).get("name"));        return convertView;    }    @Override    public boolean isChildSelectable(int groupPosition, int childPosition) {        return false;    }    //ViewHolder保存每个item内的view    static class ViewHolder{        ImageView imageView;        TextView textView;    }}

然后写两个布局文件，布局文件可参考ListView的写法。