Android ExpandableListView的使用 类似QQ好友列表

ExpandableListView效果相当于一个分组的ListView,点击组,会收缩或展开该组下的子元素,如下图: ExpandableListView的用法与ListView和GridView,Gallery 类似,都是通过一个Adapter来显示. main.xml:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical" android:layout_width="fill_parent"
    android:layout_height="fill_parent">
    <ExpandableListView android:id="@+id/elv" android:indicatorRight="160dp"
        android:layout_width="fill_parent" android:layout_height="fill_parent">
    </ExpandableListView>
    <!-- indicatorRight 设置那个小图标右边缘与 ExpandableListView左边缘的间距-->
</LinearLayout>

ElvAdapter.java

package com.test;

import java.util.ArrayList;

import android.content.Context;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseExpandableListAdapter;
import android.widget.ExpandableListView;
import android.widget.TextView;
import android.widget.LinearLayout.LayoutParams;

public class ElvAdapter extends BaseExpandableListAdapter
{
    
    ArrayList objs;
    Context context;
    ElvAdapter(Context context,ArrayList objs)
    {
        this.objs=objs;
        this.context=context;
    }
    @Override
    public Object getChild(int groupPosition, int childPosition)
    {
        // TODO Auto-generated method stub
        return objs.get(groupPosition).childs.get(childPosition);
    }

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

    @Override
    public View getChildView(int groupPosition, int childPosition, boolean isLastChild, View convertView, ViewGroup parent)
    {
        //子元素的View
        TextView tv=new TextView(context);
        tv.setText(objs.get(groupPosition).childs.get(childPosition));
        tv.setLayoutParams(new ExpandableListView.LayoutParams(ExpandableListView.LayoutParams.FILL_PARENT,ExpandableListView.LayoutParams.WRAP_CONTENT));
        return tv;
    }

    @Override
    public int getChildrenCount(int groupPosition)
    {
        // TODO Auto-generated method stub
        return objs.get(groupPosition).childs.size();
    }

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

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

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

    @Override
    public View getGroupView(int groupPosition, boolean isExpanded, View convertView, ViewGroup parent)
    {
        //分组的View
        TextView tv=new TextView(context);
        tv.setText(objs.get(groupPosition).groupName);
        ExpandableListView.LayoutParams params=new ExpandableListView.LayoutParams(ExpandableListView.LayoutParams.FILL_PARENT,60);
        tv.setLayoutParams(params);
        return tv;
    }

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

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

}
class ElvObject{
    String groupName="";
    ArrayList childs=new ArrayList();
    ElvObject(String groupName,ArrayList childs)
    {
        this.groupName=groupName;
        this.childs=childs;
    }
}

注意下面还有一个ElvObject类 主程序AndroidTestActivity.java

package com.test;

import java.util.ArrayList;

import android.app.Activity;
import android.os.Bundle;
import android.widget.ExpandableListView;

public class AndroidTestActivity extends Activity
{
    /** Called when the activity is first created. */
    ExpandableListView elv;
    ElvAdapter adapter;
    ArrayList objs=new ArrayList();
    @Override
    public void onCreate(Bundle savedInstanceState)
    {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        elv=(ExpandableListView)findViewById(R.id.elv);
        adapter=new ElvAdapter(this,objs);
        elv.setAdapter(adapter);
        ArrayList list=new ArrayList();
        list.add("aaa");
        list.add("bbb");
        list.add("ccc");
        objs.add(new ElvObject("英文",list));
        ArrayList list2=new ArrayList();
        list2.add("111");
        list2.add("222");
        list2.add("333");
        list2.add("444");
        objs.add(new ElvObject("数字",list2));
 
    }
}