ExpandableListView的用法(类似QQ好友展示)

ExpandableListView组件是android中一个比较常用的组件，当点击一个父item的时候可以将它的子item显示出来，像手机QQ中的好友列表就是实现的类型效果。使用ExpandableListView组件的关键就是设置它的adapter，这个adapter必须继承BaseExpandbaleListAdapter类，所以实现运用ExpandableListView的核心就是学会继承这个BaseExpanableListAdapter类。

下面是一个小demo：

activvity_main.xml:

<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"
tools:context=".MainActivity" >

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

</RelativeLayout>

layout_parent.xml:(父item运用的样式)

<?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/parent_textview"
android:layout_width="match_parent"
android:layout_height="50dp"
android:layout_gravity="center"
android:gravity="center" />

</LinearLayout>

layout_children.xml:(子item运用的样式)

<?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/second_textview"
android:layout_width="match_parent"
android:layout_height="40dp"
android:layout_gravity="center"
android:gravity="center" />

</LinearLayout>

MainActivity.java:

package com.example.android_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.TextView;

public class MainActivity extends Activity {

ExpandableListView mainlistview = null;
List<String> parent = null;
Map<String, List<String>> map = null;

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

initData();
mainlistview.setAdapter(new MyAdapter());
}

// 初始化数据
public void initData() {
parent = new ArrayList<String>();
parent.add("parent1");
parent.add("parent2");
parent.add("parent3");

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

List<String> list1 = new ArrayList<String>();
list1.add("child1-1");
list1.add("child1-2");
list1.add("child1-3");
map.put("parent1", list1);

List<String> list2 = new ArrayList<String>();
list2.add("child2-1");
list2.add("child2-2");
list2.add("child2-3");
map.put("parent2", list2);

List<String> list3 = new ArrayList<String>();
list3.add("child3-1");
list3.add("child3-2");
list3.add("child3-3");
map.put("parent3", list3);

}

class MyAdapter extends BaseExpandableListAdapter {

//得到子item需要关联的数据
@Override
public Object getChild(int groupPosition, int childPosition) {
String key = parent.get(groupPosition);
return (map.get(key).get(childPosition));
}

//得到子item的ID
@Override
public long getChildId(int groupPosition, int childPosition) {
return childPosition;
}

//设置子item的组件
@Override
public View getChildView(int groupPosition, int childPosition,
boolean isLastChild, View convertView, ViewGroup parent) {
String key = MainActivity.this.parent.get(groupPosition);
String info = map.get(key).get(childPosition);
if (convertView == null) {
LayoutInflater inflater = (LayoutInflater) MainActivity.this
.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
convertView = inflater.inflate(R.layout.layout_children, null);
}
TextView tv = (TextView) convertView
.findViewById(R.id.second_textview);
tv.setText(info);
return tv;
}

//获取当前父item下的子item的个数
@Override
public int getChildrenCount(int groupPosition) {
String key = parent.get(groupPosition);
int size=map.get(key).size();
return size;
}
//获取当前父item的数据
@Override
public Object getGroup(int groupPosition) {
return parent.get(groupPosition);
}

@Override
public int getGroupCount() {
return parent.size();
}

@Override
public long getGroupId(int groupPosition) {
return groupPosition;
}
//设置父item组件
@Override
public View getGroupView(int groupPosition, boolean isExpanded,
View convertView, ViewGroup parent) {
if (convertView == null) {
LayoutInflater inflater = (LayoutInflater) MainActivity.this
.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
convertView = inflater.inflate(R.layout.layout_parent, null);
}
TextView tv = (TextView) convertView
.findViewById(R.id.parent_textview);
tv.setText(MainActivity.this.parent.get(groupPosition));
return tv;
}

@Override
public boolean hasStableIds() {
return true;
}

@Override
public boolean isChildSelectable(int groupPosition, int childPosition) {
return true;
}

}
}

实现后的效果如下：





转载来自：http://my.oschina.net/summerpxy/blog/204981