Android UI控件ExpandableListView基本用法详解

<?xml version="1.0" encoding="utf-8"?>
<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"
 android:paddingBottom="@dimen/activity_vertical_margin"
 android:paddingLeft="@dimen/activity_horizontal_margin"
 android:paddingRight="@dimen/activity_horizontal_margin"
 android:paddingTop="@dimen/activity_vertical_margin"
 tools:context="com.smyhvae.expandablelistviewdemo.MainActivity">


 <ExpandableListView
  android:id="@+id/expandableListView"
  android:layout_width="match_parent"
  android:layout_height="wrap_content"
  />

</RelativeLayout> 

<?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="wrap_content"
    android:background="#cccccc"
    android:orientation="horizontal">

 <TextView
  android:id="@+id/tv_group"
  android:layout_width="wrap_content"
  android:layout_height="30dp"
  android:gravity="center"
  android:text="group text"
  android:textColor="#000000"
  />

</LinearLayout> 

 <?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="wrap_content"
    android:gravity="center"
    android:orientation="horizontal">

 <ImageView
  android:id="@+id/iv_child"
  android:layout_width="30dp"
  android:layout_height="30dp"
  android:src="@mipmap/ic_launcher"/>

 <TextView
  android:id="@+id/tv_child"
  android:layout_width="match_parent"
  android:layout_height="wrap_content"
  android:text="item text"
  android:textColor="#000000"/>

</LinearLayout> 

import android.app.Activity;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseExpandableListAdapter;
import android.widget.ExpandableListView;
import android.widget.ImageView;
import android.widget.TextView;

public class MainActivity extends Activity {

 //View
 private ExpandableListView expandableListView;

 //Model：定义的数据
 private String[] groups = {"A", "B", "C"};

 //注意，字符数组不要写成{{"A1,A2,A3,A4"}, {"B1,B2,B3,B4，B5"}, {"C1,C2,C3,C4"}}
 private String[][] childs = {{"A1", "A2", "A3", "A4"}, {"A1", "A2", "A3", "B4"}, {"A1", "A2", "A3", "C4"}};


 @Override
 protected void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  setContentView(R.layout.activity_main);
  expandableListView = (ExpandableListView) findViewById(R.id.expandableListView);

  expandableListView.setAdapter(new MyExpandableListView());

 }


 //为ExpandableListView自定义适配器
 class MyExpandableListView extends BaseExpandableListAdapter {

  //返回一级列表的个数
  @Override
  public int getGroupCount() {
   return groups.length;
  }

  //返回每个二级列表的个数
  @Override
  public int getChildrenCount(int groupPosition) { //参数groupPosition表示第几个一级列表
   Log.d("smyhvae", "-->" + groupPosition);
   return childs[groupPosition].length;
  }

  //返回一级列表的单个item（返回的是对象）
  @Override
  public Object getGroup(int groupPosition) {
   return groups[groupPosition];
  }

  //返回二级列表中的单个item（返回的是对象）
  @Override
  public Object getChild(int groupPosition, int childPosition) {
   return childs[groupPosition][childPosition]; //不要误写成groups[groupPosition][childPosition]
  }

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

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

  //每个item的id是否是固定？一般为true
  @Override
  public boolean hasStableIds() {
   return true;
  }

  //【重要】填充一级列表
  @Override
  public View getGroupView(int groupPosition, boolean isExpanded, View convertView, ViewGroup parent) {

   if (convertView == null) {
    convertView = getLayoutInflater().inflate(R.layout.item_group, null);
   } else {

   }
   TextView tv_group = (TextView) convertView.findViewById(R.id.tv_group);
   tv_group.setText(groups[groupPosition]);
   return convertView;
  }

  //【重要】填充二级列表
  @Override
  public View getChildView(int groupPosition, int childPosition, boolean isLastChild, View convertView, ViewGroup parent) {

   if (convertView == null) {
    convertView = getLayoutInflater().inflate(R.layout.item_child, null);
   }

   ImageView iv_child = (ImageView) convertView.findViewById(R.id.iv_child);
   TextView tv_child = (TextView) convertView.findViewById(R.id.tv_child);

   //iv_child.setImageResource(resId);
   tv_child.setText(childs[groupPosition][childPosition]);

   return convertView;
  }

  //二级列表中的item是否能够被选中？可以改为true
  @Override
  public boolean isChildSelectable(int groupPosition, int childPosition) {
   return true;
  }
 }


}