Android常用控件之ExpandableList的使用

先来看下什么是ExpandableListView

跟列表有点像，这种是可以折叠的列表，下面来看下是如何在代码中实现

一、在布局文件中声明一个ExpandableListView

<LinearLayout 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=".MainActivity" >    <ExpandableListView        android:id="@id/android:list"        android:layout_width="fill_parent"        android:layout_height="fill_parent"        android:drawSelectorOnTop="false" >    </ExpandableListView>    <TextView        android:id="@id/android:empty"        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:text="@string/no_data" /></LinearLayout>

二、为每个Group和Child定义一个布局

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/groupTo"        android:layout_width="fill_parent"        android:layout_height="fill_parent"        android:paddingLeft="50dp"        android:paddingTop="5dp"        android:paddingBottom="5dp"        android:textSize="20sp"        android:text="@string/no_data"/></LinearLayout>

child.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/childTo"        android:layout_width="fill_parent"        android:layout_height="fill_parent"        android:paddingLeft="60dp"        android:paddingTop="10dp"        android:paddingBottom="10dp"        android:textSize="20sp"        android:text="@string/no_data"/></LinearLayout>

以上两个文件只有缩进不一样，这样可以明显区分Group和Child

三、在代码中实现

package com.example.expandableList;import java.util.ArrayList;import java.util.HashMap;import java.util.List;import java.util.Map;import android.app.ExpandableListActivity;import android.os.Bundle;import android.view.View;import android.widget.ExpandableListAdapter;import android.widget.ExpandableListView;import android.widget.ExpandableListView.OnChildClickListener;import android.widget.SimpleExpandableListAdapter;import android.widget.Toast;import com.example.widgetdemo.R;public class expandableList extends ExpandableListActivity {ExpandableListView expandableList = null;@Overrideprotected void onCreate(Bundle savedInstanceState) {// TODO Auto-generated method stubsuper.onCreate(savedInstanceState);setContentView(R.layout.expandable);expandableList = getExpandableListView();// 写入当前组数List<Map<String, String>> groups = new ArrayList<Map<String, String>>();Map<String, String> group1 = new HashMap<String, String>();group1.put("group", "广东省");Map<String, String> group2 = new HashMap<String, String>();group2.put("group", "江西省");groups.add(group1);groups.add(group2);// 写入第一组的数据List<Map<String, String>> child1 = new ArrayList<Map<String, String>>();Map<String, String> childData1 = new HashMap<String, String>();childData1.put("child", "广州市");Map<String, String> childData2 = new HashMap<String, String>();childData2.put("child", "深圳市");Map<String, String> childData3 = new HashMap<String, String>();childData3.put("child", "东莞市");child1.add(childData1);child1.add(childData2);child1.add(childData3);// 写入第二组的数据List<Map<String, String>> child2 = new ArrayList<Map<String, String>>();Map<String, String> childData4 = new HashMap<String, String>();childData4.put("child", "赣州市");Map<String, String> childData5 = new HashMap<String, String>();childData5.put("child", "南昌市");Map<String, String> childData6 = new HashMap<String, String>();childData6.put("child", "九江市");Map<String, String> childData7 = new HashMap<String, String>();childData7.put("child", "吉安市");child2.add(childData4);child2.add(childData5);child2.add(childData6);child2.add(childData7);List<List<Map<String, String>>> childs = new ArrayList<List<Map<String, String>>>();childs.add(child1);childs.add(child2);SimpleExpandableListAdapter sela = new SimpleExpandableListAdapter(expandableList.this, groups, R.layout.group,new String[] { "group" }, new int[] { R.id.groupTo }, childs,R.layout.child, new String[] { "child" },new int[] { R.id.childTo });setListAdapter(sela);expandableList.setOnChildClickListener(new expandableListListener());}//为ExpandableListView编写监听器class expandableListListener implements OnChildClickListener {@Overridepublic boolean onChildClick(ExpandableListView parent, View v,int groupPosition, int childPosition, long id) {// TODO Auto-generated method stubSystem.out.println("group = " + groupPosition + " child = "+ childPosition + " id = " + id);ExpandableListAdapter exAdapter = parent.getExpandableListAdapter();// 获得选中项的HashMap对象Map<String, String> childMap = (HashMap<String, String>) exAdapter.getChild(groupPosition, childPosition);String contentChild = childMap.get("child");Map<String, String> groupMap = (HashMap<String, String>) exAdapter.getGroup(groupPosition);String contentGroup = groupMap.get("group");Toast.makeText(getApplicationContext(),"你选择了第" + groupPosition + " 个Group， 第 " + childPosition+ " 个Child的值是：" + contentChild + " Group的值是 " + contentGroup,Toast.LENGTH_LONG).show();return false;}}}

关于如何获取选中的值，我查看文档终于找到ExpandableListAdapter，在这个适配器有获取那个child和group的方法。

下面看下效果

最后还是传上源码

点击打开链接

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