ExpandableListView简单用法

一、ExpandableListView

1.简单介绍

       ExpandableListView是一个垂直滚动的显示两个级别（group,child）列表项的视图。列表项来自ExpandableListAdapter,gourp可以单独展开。

2.常用方法

      expandGroup(int groupPos):在分组列表视图中展开一组

     setSelectedGroup(int groupPosition):设置选择指定的组

    setSelectedChild(ing groupPosition,int childPosition,boolean shouldExpandGroup):设置选择指定的子项

    getPackedPositionGroup(long packedPosition):返回所选择的组

    getPackedPositionForChild(ing groupPosition,int childPosition):返回所选择的子项

    getPackedPositionType(long packedPosition):返回所选择的类型（group.child）

    isGroupExpanded(int groupPosition):判断此组是否展开

    ExpandableListContextMenuInfo info = (ExpandableListMenuInfo)item.getMenuInfo();

    String title = ((TextView)info.targetView).getText().toString();

    int type = ExpandableListView.getPackedPositionType(info.packedPosition);

    if(type == ExpandableListView.PACKED_POSITION_TYPE_CHILD){

        int gourpPos = ExpandableListView.getPackedPositionGroup(info.packedPosition);

        int childPos = ExpandableListView.getPackedPositiionChild(info.packedPosition);

    }

二、ExpandableListAdapter

    一个接口，将基础数据链接到ExpandableListView.此接口的实现将提供访问child项的数据（由group分类）并实例化child和group。

三、简单实现代码

main.xml:定义Activity的界面布局:
<?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:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:id="@+id/mExpandableListView"
    />
</LinearLayout>

group.xml:定义一级列表的布局方式:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
 xmlns:android="http://schemas.android.com/apk/res/android"
 android:orientation = "horizontal"
 android:layout_width="fill_parent"
 android:layout_height="fill_parent">
 <TextView
  android:id = "@+id/group_tv"
  android:layout_width = "match_parent"
  android:layout_height = "match_parent"
  android:paddingLeft = "60px"
  android:paddingTop = "10px"
  android:paddingBottom = "10px"
  android:textSize = "26sp"/>
</LinearLayout>

child.xml:定义二级列表的布局方式:
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
 xmlns:android="http://schemas.android.com/apk/res/android"
 android:orientation = "horizontal"
 android:layout_width="match_parent"
 android:layout_height="match_parent">
 <ImageView
  android:layout_gravity = "center_vertical"
  android:id = "@+id/child_iv"
  android:layout_width = "70px"
  android:layout_height = "70px"
  android:paddingLeft = "30px"
  android:paddingTop = "2px"
  android:paddingBottom = "5px"
  android:src = "@drawable/icon"/>
 <TextView
  android:layout_gravity = "center_vertical"
  android:id = "@+id/child_tv"
  android:layout_width = "fill_parent"
  android:layout_height = "fill_parent"
  android:paddingLeft = "30px"
  android:paddingTop = "10px"
  android:paddingBottom = "5px"
  android:textSize = "30sp"/>
</LinearLayout>
   

Activity代码：

package test.expandableListView;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import android.app.Activity;
import android.content.Context;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseExpandableListAdapter;
import android.widget.ExpandableListView;
import android.widget.ImageView;
import android.widget.LinearLayout;
import android.widget.TextView;

public class TestExpandableListView extends Activity
{
 @Override
 public void onCreate(Bundle savedInstanceState)
 {
  super.onCreate(savedInstanceState);
  setContentView(R.layout.main);
  ExpandableListView elv = (ExpandableListView)findViewById(R.id.mExpandableListView);

  //准备一级列表中显示的数据:2个一级列表,分别显示"group1"和"group2"
  List<Map<String, String>> groups = new ArrayList<Map<String, String>>();
  Map<String, String> group1 = new HashMap<String, String>();
  group1.put("group", "group1");
  Map<String, String> group2 = new HashMap<String, String>();
  group2.put("group", "group2");
  groups.add(group1);
  groups.add(group2);

  //准备第一个一级列表中的二级列表数据:两个二级列表,分别显示"childData1"和"childData2"
  List<Map<String, String>> child1 = new ArrayList<Map<String, String>>();
  Map<String, String> child1Data1 = new HashMap<String, String>();
  child1Data1.put("child", "child1Data1");
  Map<String, String> child1Data2 = new HashMap<String, String>();
  child1Data2.put("child", "child1Data2");
  child1.add(child1Data1);
  child1.add(child1Data2);

  //准备第二个一级列表中的二级列表数据:一个二级列表,显示"child2Data1"
  List<Map<String, String>> child2 = new ArrayList<Map<String, String>>();
  Map<String, String> child2Data1 = new HashMap<String, String>();
  child2Data1.put("child", "child2Data1");
  child2.add(child2Data1);

  //用一个list对象保存所有的二级列表数据
  List<List<Map<String, String>>> childs = new ArrayList<List<Map<String, String>>>();
  childs.add(child1);
  childs.add(child2);

  ExpandableAdapter viewAdapter = new ExpandableAdapter(this, groups, childs);
  elv.setAdapter(viewAdapter);
 }

 //自定义的ExpandListAdapter
 class ExpandableAdapter extends BaseExpandableListAdapter
 {
  private Context context;
  List<Map<String, String>> groups;
  List<List<Map<String, String>>> childs;

  /*
   * 构造函数:
   * 参数1:context对象
   * 参数2:一级列表数据源
   * 参数3:二级列表数据源
   */
  public ExpandableAdapter(Context context, List<Map<String, String>> groups, List<List<Map<String, String>>> childs)
  {
   this.groups = groups;
   this.childs = childs;
   this.context = context;
  }

  public Object getChild(int groupPosition, int childPosition)
  {
   return childs.get(groupPosition).get(childPosition);
  }

  public long getChildId(int groupPosition, int childPosition)
  {
   return childPosition;
  }

  //获取二级列表的View对象
  public View getChildView(int groupPosition, int childPosition, boolean isLastChild, View convertView,
    ViewGroup parent)
  {
   @SuppressWarnings("unchecked")
   String text = ((Map<String, String>) getChild(groupPosition, childPosition)).get("child");
   LayoutInflater layoutInflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);

   //获取二级列表对应的布局文件, 并将其各元素设置相应的属性
   LinearLayout linearLayout = (LinearLayout) layoutInflater.inflate(R.layout.child, null);
   TextView tv = (TextView) linearLayout.findViewById(R.id.child_tv);
   tv.setText(text);
   ImageView imageView = (ImageView)linearLayout.findViewById(R.id.child_iv);
   imageView.setImageResource(R.drawable.icon);

   return linearLayout;
  }

  public int getChildrenCount(int groupPosition)
  {
   return childs.get(groupPosition).size();
  }

  public Object getGroup(int groupPosition)
  {
   return groups.get(groupPosition);
  }

  public int getGroupCount()
  {
   return groups.size();
  }

  public long getGroupId(int groupPosition)
  {
   return groupPosition;
  }

  //获取一级列表View对象
  public View getGroupView(int groupPosition, boolean isExpanded, View convertView, ViewGroup parent)
  {
   String text = groups.get(groupPosition).get("group");
   LayoutInflater layoutInflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);

   //获取一级列表布局文件,设置相应元素属性
   LinearLayout linearLayout = (LinearLayout) layoutInflater.inflate(R.layout.group, null);
   TextView textView = (TextView)linearLayout.findViewById(R.id.group_tv);
   textView.setText(text);

   return linearLayout;
  }

  public boolean hasStableIds()
  {
   return false;
  }

  public boolean isChildSelectable(int groupPosition, int childPosition)
  {
   return false;
  }

 }
}

截图：