【安卓笔记】ExpandableListView的使用

实现效果：

即可伸展的ListView

其实跟普通的ListView使用没啥区别，只是ListView改为了ExpandableListView，另外适配器由BaseAdapter也换成了BaseExpandableListAdapter。

步骤：

1.编写布局文件。

分为三个，分别是主布局，group分组布局，group item布局：

activity_main.xml:

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context="com.example.expandablelistviewdemo.MainActivity" >
    <ExpandableListView
        android:id="@+id/elv"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:divider="#000"
        android:dividerHeight="2.5dp"
        android:indicatorLeft="?android:attr/expandableListPreferredItemIndicatorLeft" >
    </ExpandableListView>
</RelativeLayout>

list_group.xml:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical" >
    <TextView
        android:id="@+id/listTitle"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:paddingBottom="10dp"
        android:paddingLeft="?android:attr/expandableListPreferredItemPaddingLeft"
        android:paddingTop="10dp"
        android:textColor="#A4C739" />
</LinearLayout>

list_item.xml:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical" >
    <TextView
        android:id="@+id/expandedListItem"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:paddingBottom="10dp"
        android:paddingLeft="?android:attr/expandableListPreferredChildPaddingLeft"
        android:paddingTop="10dp" />
</LinearLayout>

2.编写适配器代码：

package com.example.expandablelistviewdemo;
import java.util.HashMap;
import java.util.List;
import android.content.Context;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseExpandableListAdapter;
import android.widget.TextView;
public class MyExpandableListAdapter extends BaseExpandableListAdapter
{
	private Context mContext;
	private List<String> expandableListTitle;
	private HashMap<String, List<String>> expandableListDetail;

	public MyExpandableListAdapter(List<String> expandableListTitle,HashMap<String,List<String>> expandableListDetail,Context mContext)
	{
		this.expandableListDetail = expandableListDetail;
		this.expandableListTitle = expandableListTitle;
		this.mContext = mContext;
	}

	@Override
	public int getGroupCount()//分组数
	{
		return this.expandableListTitle.size();
	}
	@Override
	public int getChildrenCount(int groupPosition)//分组内的item数
	{
		return this.expandableListDetail.get(expandableListTitle.get(groupPosition)).size();
	}
	@Override
	public Object getGroup(int groupPosition)//获取分组数据
	{
		return this.expandableListTitle.get(groupPosition);
	}
	@Override
	public Object getChild(int groupPosition, int childPosition)//获取第几分组第几个item的数据
	{
		return this.expandableListDetail.get(this.expandableListTitle.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;
	}
	@Override
	public View getGroupView(int groupPosition, boolean isExpanded,
			View convertView, ViewGroup parent)
	{
		String data = this.expandableListTitle.get(groupPosition);
		if(convertView == null)
		{
			convertView = View.inflate(mContext,R.layout.list_group, null);
		}
		TextView tv = (TextView) convertView.findViewById(R.id.listTitle);
		tv.setText(data);
		return convertView;
	}
	@Override
	public View getChildView(int groupPosition, int childPosition,
			boolean isLastChild, View convertView, ViewGroup parent)
	{
//		String data = this.expandableListDetail.get(this.expandableListTitle.get(groupPosition)).get(childPosition);
		String data = (String) this.getChild(groupPosition, childPosition);
		if(convertView == null)
		{
			convertView = View.inflate(mContext, R.layout.list_item, null);
		}
		TextView tv = (TextView) convertView.findViewById(R.id.expandedListItem);
		tv.setText(data);
		return convertView;
	}
	@Override
	public boolean isChildSelectable(int groupPosition, int childPosition)
	{
		return true;
	}
}

可以看到，适配器中有两个getView的方法，分别去构造group和child的view。

3.构造数据源

package com.example.expandablelistviewdemo;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
public class ExpandableListDataPump
{
	public static HashMap<String, List<String>> getData()
	{
		HashMap<String, List<String>> expandableListDetail = new HashMap<String, List<String>>();
		List<String> technology = new ArrayList<String>();
		technology.add("Beats sued for noise-cancelling tech");
		technology.add("Wikipedia blocks US Congress edits");
		technology.add("Google quizzed over deleted links");
		technology.add("Nasa seeks aid with Earth-Mars links");
		technology.add("The Good, the Bad and the Ugly");
		List<String> entertainment = new ArrayList<String>();
		entertainment.add("Goldfinch novel set for big screen");
		entertainment.add("Anderson stellar in Streetcar");
		entertainment.add("Ronstadt receives White House honour");
		entertainment.add("Toronto to open with The Judge");
		entertainment.add("British dancer return from Russia");
		List<String> science = new ArrayList<String>();
		science.add("Eggshell may act like sunblock");
		science.add("Brain hub predicts negative events");
		science.add("California hit by raging wildfires");
		science.add("Rosetta's comet seen in close-up");
		science.add("Secret of sandstone shapes revealed");
		expandableListDetail.put("TECHNOLOGY NEWS", technology);
		expandableListDetail.put("ENTERTAINMENT NEWS", entertainment);
		expandableListDetail.put("SCIENCE & ENVIRONMENT NEWS", science);
		return expandableListDetail;
	}
}

4.编写主界面的代码

package com.example.expandablelistviewdemo;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import android.annotation.SuppressLint;
import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.widget.ExpandableListView;
import android.widget.ExpandableListView.OnChildClickListener;
import android.widget.ExpandableListView.OnGroupCollapseListener;
import android.widget.ExpandableListView.OnGroupExpandListener;
import android.widget.Toast;
public class MainActivity extends Activity
{
	private ExpandableListView elv = null;
	private MyExpandableListAdapter adapter = null;

	@Override
	protected void onCreate(Bundle savedInstanceState)
	{
		super.onCreate(savedInstanceState);
		setContentView(R.layout.activity_main);

		elv = (ExpandableListView) findViewById(R.id.elv);

		final HashMap<String,List<String>> itemData = ExpandableListDataPump.getData();
		final List<String> title = new ArrayList<String>(itemData.keySet());
		adapter = new MyExpandableListAdapter(title,itemData,this);

		elv.setAdapter(adapter);

		//去掉箭头
//		elv.setGroupIndicator(null);

		//收缩
		elv.setOnGroupCollapseListener(new OnGroupCollapseListener()
		{

			@Override
			public void onGroupCollapse(int groupPosition)
			{
				Toast.makeText(MainActivity.this,title.get(groupPosition)+" group collapse..... ", 0).show();
			}
		});
		//伸展
		elv.setOnGroupExpandListener(new OnGroupExpandListener()
		{
			@Override
			public void onGroupExpand(int groupPosition)
			{
				Toast.makeText(MainActivity.this,title.get(groupPosition)+" group expand... ", 0).show();
			}
		});
		//子条目点击
		elv.setOnChildClickListener(new OnChildClickListener()
		{
			@Override
			public boolean onChildClick(ExpandableListView parent, View v,
					int groupPosition, int childPosition, long id)
			{
				Toast.makeText(MainActivity.this,itemData.get(title.get(groupPosition)).get(childPosition)+" click", 0).show();
				return false;
			}
		});

	}
}

ok，完成。

这里需要注意的是ExpandableListView有多个监听器，group收缩和伸展以及子条目点击等等，按需监听。

另外，默认情况下显示的时候有个箭头，你可以通过setGroupIndicator方法设置你需要的标识。

源码地址：https://github.com/Rowandjj/ExpandableListViewDemo