ExpandableListView显示省市列表（一）

上午面试被问到某app中离线状态下城市选择如何实现，瞎扯一番过后，看到了面试官鄙视的眼神，下午开始写了个demo实现此功能。

效果图如下：



关键技术点总结：

<pre name="code" class="java"><span style="font-size:18px;">1 List<String> proList 存放省份信息，
Map<String,List> cityData 存放城市信息，key为"省份名"，List存放该省份对应的城市列表。

2 </span><span style="font-size:18px;">ExpandableListView</span><span style="font-size:18px;"> 默认子项是折叠的，且点击group可在折叠与不折叠之前切换
要设置初始化子项不折叠，且点击group不折叠，需用以下代码：
//设置所有子项不折叠
eListView.setAdapter(adapter);
for(int i=0;i<proList.size();i++){
eListView.expandGroup(i);
}
//点击group 不折叠
eListView.setOnGroupClickListener(new OnGroupClickListener() {

@Override
public boolean onGroupClick(ExpandableListView parent, View v,
int groupPosition, long id) {
// TODO Auto-generated method stub
return true;
}
});
</span>

<pre name="code" class="java"><span style="font-size:18px;">
3 Android_ExpandableListView_子item响应点击事件
  如果使用ExpandableListView，需要子item响应一个事件，比如重新启动一个新的activity，需要满足下面的条件：
    (1) 修改Adapter返回值
        覆写BaseExpandableListAdapter的isChildSelectable()的返回值为true;
    (2) 绑定监听器
        调用ExpandableListView对象的setOnChildClickListener()方法，为其绑定监听器
</span>

工程截图：



xml：

代码：

<span style="color:#330000;"><strong><span style="font-size:18px;">xml： </span>
</strong><span style="font-size:18px;"><strong>activity_main.xml </strong>   </span></span><pre name="code" class="html"><span style="font-size:18px;color:#330000;"><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/eListView"
android:layout_width="match_parent"
android:layout_height="match_parent"
/>

</LinearLayout>
<strong>view_child.xml</strong>
</span><pre name="code" class="html"><span style="font-size:18px;color:#330000;"><?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="wrap_content"
android:layout_height="wrap_content">
<TextView
android:id="@+id/group_city"
android:background="#FFFFFF"
android:layout_width="match_parent"
android:layout_height="50dp"
android:textSize="22sp"
android:textColor="#000000"
android:paddingLeft="10dp"
android:gravity="center_vertical"
/>

</RelativeLayout></span>

view_group.xml

<?xml version="1.0" encoding="utf-8"?>

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"

android:layout_width="wrap_content"

android:layout_height="wrap_content">

<TextView

android:id="@+id/group_provice"

android:background="#B4B595"

android:layout_width="match_parent"

android:layout_height="50dp"

android:textSize="25sp"

android:textColor="#FFFFFF"

android:paddingLeft="10dp"

android:gravity="center_vertical"

/>

</RelativeLayout>

MainActivity

<span style="font-size:18px;">package com.example.provincecity;

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

import android.app.Activity;
import android.database.DataSetObserver;
import android.os.Bundle;
import android.view.View;
import android.view.ViewGroup;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.ExpandableListAdapter;
import android.widget.ExpandableListView;
import android.widget.ExpandableListView.OnChildClickListener;
import android.widget.ExpandableListView.OnGroupClickListener;
import android.widget.TextView;
import android.widget.Toast;

public class MainActivity extends Activity {
private ExpandableListView eListView;
private List<String> proList;
private Map<String,List> cityData;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
getData();
eListView=(ExpandableListView) findViewById(R.id.eListView);

ExpandableListAdapter adapter=new ExpandableListAdapter() {

@Override
public void unregisterDataSetObserver(DataSetObserver observer) {
// TODO Auto-generated method stub

}

@Override
public void registerDataSetObserver(DataSetObserver observer) {
// TODO Auto-generated method stub

}

@Override
public void onGroupExpanded(int groupPosition) {
// TODO Auto-generated method stub

}

@Override
public void onGroupCollapsed(int groupPosition) {
// TODO Auto-generated method stub

}

@Override
public boolean isEmpty() {
// TODO Auto-generated method stub
return false;
}

@Override
public boolean isChildSelectable(int groupPosition, int childPosition) {
// TODO Auto-generated method stub
return true;
}

@Override
public boolean hasStableIds() {
// TODO Auto-generated method stub
return false;
}

@Override
public View getGroupView(int groupPosition, boolean isExpanded,
View convertView, ViewGroup parent) {
HolderView holderView=new HolderView();
if(convertView==null){
holderView=new HolderView();
convertView=View.inflate(getApplicationContext(), R.layout.view_group, null);
holderView.proText=(TextView) convertView.findViewById(R.id.group_provice);
convertView.setTag(holderView);
}else{
holderView=(HolderView) convertView.getTag();
}
holderView.proText.setText(proList.get(groupPosition));
return convertView;
}

@Override
public long getGroupId(int groupPosition) {
// TODO Auto-generated method stub
return 0;
}

@Override
public int getGroupCount() {
// TODO Auto-generated method stub
return proList==null?0:proList.size();
}

@Override
public Object getGroup(int groupPosition) {
// TODO Auto-generated method stub
return proList.get(groupPosition);
}

@Override
public long getCombinedGroupId(long groupId) {
// TODO Auto-generated method stub
return 0;
}

@Override
public long getCombinedChildId(long groupId, long childId) {
// TODO Auto-generated method stub
return 0;
}

@Override
public int getChildrenCount(int groupPosition) {
// TODO Auto-generated method stub
String pro=proList.get(groupPosition);
ArrayList<String> cityList = (ArrayList<String>) cityData.get(pro);
return cityList.size();
}

@Override
public View getChildView(int groupPosition, int childPosition,
boolean isLastChild, View convertView, ViewGroup parent) {
String key=(String) getChild(groupPosition, childPosition);
View view= View.inflate(getApplicationContext(), R.layout.view_child,null);
TextView textView=(TextView)view.findViewById(R.id.group_city);
textView.setText(key);
return view;
}

@Override
public long getChildId(int groupPosition, int childPosition) {
// TODO Auto-generated method stub
return 0;
}

@Override
public Object getChild(int groupPosition, int childPosition) {
String pro=proList.get(groupPosition);

return cityData.get(pro).get(childPosition);
}

@Override
public boolean areAllItemsEnabled() {
// TODO Auto-generated method stub
return false;
}
};
//设置所有子项不折叠
eListView.setAdapter(adapter);
for(int i=0;i<proList.size();i++){
eListView.expandGroup(i);
}
//点击group 不折叠
eListView.setOnGroupClickListener(new OnGroupClickListener() {

@Override
public boolean onGroupClick(ExpandableListView parent, View v,
int groupPosition, long id) {
// TODO Auto-generated method stub
return true;
}
});
//点击子项弹出城市信息
eListView.setOnChildClickListener(new OnChildClickListener() {

@Override
public boolean onChildClick(ExpandableListView parent, View v,
int groupPosition, int childPosition, long id) {
String pro=proList.get(groupPosition);
String city=(String) cityData.get(pro).get(childPosition);
Toast.makeText(getApplicationContext(), pro+"省"+city+"市", 1).show();
// TODO Auto-generated method stub
return false;
}
});

}

class HolderView {
TextView proText;
}
//获取省份和城市列表
private void getData() {
// TODO Auto-generated method stub
proList=new ArrayList<String>();
proList.add("湖北");
proList.add("湖南");
proList.add("广东");

cityData=new HashMap<String, List>();

List<String> huBeiCityList=new ArrayList<String>();
huBeiCityList.add("武汉");
huBeiCityList.add("襄阳");
huBeiCityList.add("宜昌");
huBeiCityList.add("荆州");
huBeiCityList.add("十堰");
cityData.put("湖北",huBeiCityList);

List<String> huNanCityList=new ArrayList<String>();
huNanCityList.add("长沙");
huNanCityList.add("常德");
huNanCityList.add("衡阳");
huNanCityList.add("株洲");
cityData.put("湖南",huNanCityList);

List<String> guangDongCityList=new ArrayList<String>();
guangDongCityList.add("广州");
guangDongCityList.add("深圳");
guangDongCityList.add("珠海");
cityData.put("广东",guangDongCityList);

}

}</span>