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));
 
	}
}

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