package com.devin;
import java.util.ArrayList;
import android.app.Activity;
import android.graphics.Color;
import android.graphics.drawable.ColorDrawable;
import android.os.Bundle;
import android.view.Gravity;
import android.view.View;
import android.view.View.OnClickListener;
import android.view.ViewGroup;
import android.widget.BaseExpandableListAdapter;
import android.widget.ExpandableListAdapter;
import android.widget.ExpandableListView;
import android.widget.ImageView;
import android.widget.LinearLayout;
import android.widget.TextView;public class PadTestActivity extends Activity {protected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);ArrayList<String> groupList = new ArrayList<String>();for (int i = 0; i < 3; i++) {groupList.add("title");}ArrayList<String> itemList1 = new ArrayList<String>();itemList1.add("Item1");itemList1.add("Item2");ArrayList<String> itemList2 = new ArrayList<String>();itemList2.add("Item1");itemList2.add("Item2");itemList2.add("Item3");ArrayList<String> itemList3 = new ArrayList<String>();itemList3.add("Item1");itemList3.add("Item2");itemList3.add("Item3");itemList3.add("Item4");ArrayList<ArrayList<String>> childList = new ArrayList<ArrayList<String>>();childList.add(itemList1);childList.add(itemList2);childList.add(itemList3);ExpandableListView list = new ExpandableListView(this);ExpandableListAdapter mAdapter = new MyExpandableListAdapter(groupList, childList);list.setAdapter(mAdapter);list.setCacheColorHint(0x00000000);list.setSelector(new ColorDrawable(Color.TRANSPARENT));list.setGroupIndicator(null);for (int i = 0; i < mAdapter.getGroupCount(); i++) {list.expandGroup(i);}setContentView(list);}private class MyExpandableListAdapter extends BaseExpandableListAdapter {private ArrayList<String> groupList;private ArrayList<ArrayList<String>> childList;MyExpandableListAdapter(ArrayList<String> groupList, ArrayList<ArrayList<String>> childList) {this.groupList = groupList;this.childList = childList;}public Object getChild(int groupPosition, int childPosition) {return childList.get(groupPosition).get(childPosition);}private int selectedGroupPosition = -1;private int selectedChildPosition = -1;public void setSelectedPosition(int selectedGroupPosition, int selectedChildPosition) {this.selectedGroupPosition = selectedGroupPosition;this.selectedChildPosition = selectedChildPosition;}public long getChildId(int groupPosition, int childPosition) {return childPosition;}public int getChildrenCount(int groupPosition) {return childList.get(groupPosition).size();}public View getChildView(final int groupPosition, final int childPosition, boolean isLastChild, View convertView, ViewGroup parent) {TextView textView = null;if (convertView == null) {textView = new TextView(PadTestActivity.this);textView.setPadding(32, 10, 0, 10);convertView = textView;} else {textView = (TextView) convertView;}textView.setText(getChild(groupPosition, childPosition).toString());if (groupPosition == selectedGroupPosition) {if (childPosition == selectedChildPosition) {textView.setBackgroundColor(0xffb6ddee);} else {textView.setBackgroundColor(Color.TRANSPARENT);}}textView.setOnClickListener(new OnClickListener() {public void onClick(View v) {setSelectedPosition(groupPosition, childPosition);notifyDataSetChanged();}});return textView;}public Object getGroup(int groupPosition) {return groupList.get(groupPosition);}public int getGroupCount() {return groupList.size();}public long getGroupId(int groupPosition) {return groupPosition;}public View getGroupView(int groupPosition, boolean isExpanded, View convertView, ViewGroup parent) {LinearLayout cotain = new LinearLayout(PadTestActivity.this);cotain.setPadding(0, 10, 0, 10);cotain.setGravity(Gravity.CENTER_VERTICAL);ImageView imgIndicator = new ImageView(PadTestActivity.this);TextView textView = new TextView(PadTestActivity.this);textView.setText(getGroup(groupPosition).toString());textView.setPadding(5, 0, 0, 0);if (isExpanded) {imgIndicator.setBackgroundResource(R.drawable.macro_minus);} else {imgIndicator.setBackgroundResource(R.drawable.macro_plus);}cotain.addView(imgIndicator);cotain.addView(textView);return cotain;}public boolean hasStableIds() {return true;}public boolean isChildSelectable(int groupPosition, int childPosition) {return true;}}
}

上述代码中，过向BaseExpandableListAdapter传递两个动态数组groupList(表示目录头信息)和childList（表示子项信息）来构建目录，一方面能够实现动态的添加数据，另一方面简化了实现，一举两得。另外，重写的BaseExpandableListAdapter，如果应用在实际项目中，需要对getGroupView()和getChildView()方法进行构建缓存(和ListView构建一样)，以便优化性能和防止内存泄漏。

转自：http://www.cnblogs.com/devinzhang/archive/2012/07/18/2596998.html