Android Listview 分页加载数据（滑到底部加载）

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent" >

<ListView
android:id="@+id/listView"
android:layout_width="match_parent"
android:layout_height="match_parent" >
</ListView>

</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="match_parent"
android:orientation="vertical" >

<TextView
android:id="@+id/textview"
android:text="1"
android:layout_width="wrap_content"
android:layout_height="wrap_content" />

</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="match_parent"
android:orientation="vertical" >

<Button
android:id="@+id/more"
android:text="More"
android:layout_width="match_parent"
android:layout_height="wrap_content" />

</LinearLayout>

package com.example.pullloadingmore;

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

import android.content.Context;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.TextView;

public class MyAdatpter extends BaseAdapter {

private static Map<Integer,View> m=new HashMap<Integer,View>();

private List<String> items;
private LayoutInflater inflater;

public MyAdatpter(List<String> items, Context context) {
super();
this.items = items;
this.inflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
}

@Override
public int getCount() {
// TODO Auto-generated method stub
return items.size();
}

@Override
public Object getItem(int position) {
// TODO Auto-generated method stub
return items.get(position);
}

@Override
public long getItemId(int position) {
// TODO Auto-generated method stub
return position;
}

@Override
public View getView(int position, View contentView, ViewGroup arg2) {
// TODO Auto-generated method stub
contentView=m.get(position);
if(contentView==null){
contentView=inflater.inflate(R.layout.items, null);
TextView text=(TextView) contentView.findViewById(R.id.textview);
text.setText(items.get(position));
}
m.put(position, contentView);
return contentView;
}

public void addItem(String item) {
items.add(item);
}

}

package com.example.pullloadingmore;

import java.util.ArrayList;
import java.util.List;

import android.app.Activity;
import android.os.Bundle;
import android.os.Handler;
import android.util.Log;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.AbsListView;
import android.widget.AbsListView.OnScrollListener;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.Button;
import android.widget.ListView;
import android.widget.Toast;

public class MainActivity extends Activity implements OnScrollListener  {
List<String> items = new ArrayList<String>();
private ListView listView;
private int visibleLastIndex = 0;   //最后的可视项索引
private int visibleItemCount;       // 当前窗口可见项总数
private MyAdatpter adapter;
private View loadMoreView;
private Button loadMoreButton;
private Handler handler = new Handler();

@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);

loadMoreView = getLayoutInflater().inflate(R.layout.more, null);
loadMoreButton = (Button) loadMoreView.findViewById(R.id.more);
loadMoreButton.setOnClickListener(new OnClickListener() {

@Override
public void onClick(View v) {
// TODO Auto-generated method stub
loadMoreButton.setText("正在加载...");   //设置按钮文字loading
handler.postDelayed(new Runnable() {
@Override
public void run() {

loadData();

adapter.notifyDataSetChanged(); //数据集变化后,通知adapter
listView.setSelection(visibleLastIndex - visibleItemCount + 1); //设置选中项

loadMoreButton.setText("加载更多");    //恢复按钮文字
}
}, 1000);
}
});
listView = (ListView) this.findViewById(R.id.listView);

listView.addFooterView(loadMoreView);   //设置列表底部视图
// listView.addHeaderView(v)    //设置列表顶部视图

initAdapter();

listView.setAdapter(adapter);                //自动为id是list的ListView设置适配器

listView.setOnScrollListener(this);     //添加滑动监听
listView.setOnItemClickListener(new OnItemClickListener() {

@Override
public void onItemClick(AdapterView<?> arg0, View view,
int position, long arg3) {
// TODO Auto-generated method stub
Toast.makeText(getApplicationContext(), items.get(position),Toast.LENGTH_SHORT).show();
}
});
}

/**
* 初始化适配器
*/
private void initAdapter() {

for (int i = 0; i < 20; i++) {
items.add(String.valueOf(i + 1));
}
adapter = new MyAdatpter(items,this);
}

/**
* 滑动时被调用
*/
@Override
public void onScroll(AbsListView view, int firstVisibleItem, int visibleItemCount, int totalItemCount) {
this.visibleItemCount = visibleItemCount;
visibleLastIndex = firstVisibleItem + visibleItemCount - 1;
}

/**
* 滑动状态改变时被调用
*/
@Override
public void onScrollStateChanged(AbsListView view, int scrollState) {
int itemsLastIndex = adapter.getCount() - 1;    //数据集最后一项的索引
int lastIndex = itemsLastIndex + 1;             //加上底部的loadMoreView项
if (scrollState == OnScrollListener.SCROLL_STATE_IDLE && visibleLastIndex == lastIndex) {
//如果是自动加载,可以在这里放置异步加载数据的代码
Log.i("LOADMORE", "loading...");
loadData();
adapter.notifyDataSetChanged();
}
}

/**
* 模拟加载数据
*/
private void loadData() {
int count = adapter.getCount();
for (int i = count; i < count + 20; i++) {
adapter.addItem(String.valueOf(i + 1));
}
}

}