Android 實現ListView滾動到底部自動加載數據

大概說下原理:

1.利用ListView的footer，來顯示提示信息比如：正在加載中，也可以換成圖標，或者自定義的控件；

2.利用OnScrollListener，滾動條監聽器，判斷滾動條滾動到底部的時候，設置listview的footer，在開啓子線程加載數據，數據加載完畢後通知listview的adapter更新界面，在移除footer。

先上效果圖：

MainActivity.java

package com.example.list;

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

import android.app.Activity;
import android.os.Bundle;
import android.os.Handler;
import android.os.Message;
import android.view.LayoutInflater;
import android.view.View;
import android.widget.AbsListView;
import android.widget.AbsListView.OnScrollListener;
import android.widget.ListView;
import android.widget.Toast;

public class MainActivity extends Activity implements OnScrollListener{

	ListView listView;
	List<Map<String,String>> list = new ArrayList();
	MyAdapter adapter;
	//底部footer
	View footer;
	//最大頁數
	int maxPage = 5;
	//當前頁數
	int page = 1;
	//每頁顯示數
	int pageSize = 20;
	//是否加載數據中
	boolean isLoading = false;
	//Toast顯示狀態
	boolean isToast = false;
	
	Handler handler = new Handler(){
		@Override
		public void handleMessage(Message msg) {
			// TODO Auto-generated method stub
			if(msg.what == 1){
				//得到消息中的數據
				list.addAll((List)msg.obj);
				//告訴適配器，數據變化了，從新加載listview
				adapter.notifyDataSetChanged();
				//移除底部footer
				listView.removeFooterView(footer);
				//當前頁數增加
				page++;
				//設置加載中爲false
				isLoading = false;
			}else if(msg.what == 0){
				//設置加載中爲false
				isToast = false;
			}
		}
	};
	
	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.activity_main);
		listView = (ListView)findViewById(R.id.lv);
		footer = LayoutInflater.from(this).inflate(R.layout.footer, null);
		list = DataService.getData(pageSize, page);
		adapter = new MyAdapter(this, list);
		//添加footer必須在setAdapter之前，不然會顯示不出來
		listView.addFooterView(footer);
		listView.setAdapter(adapter);
		listView.setOnScrollListener(this);
		listView.removeFooterView(footer);
	}
	/**
	 * 滾動條狀態，1是滑動，0是靜止
	 */
	@Override
	public void onScrollStateChanged(AbsListView view, int scrollState) {
		// TODO Auto-generated method stub
//		if(SCROLL_STATE_TOUCH_SCROLL == scrollState){
//			System.out.println("SCROLL_STATE_TOUCH_SCROLL  "+scrollState );
//		}else if(SCROLL_STATE_IDLE == scrollState){
//			System.out.println("SCROLL_STATE_IDLE  "+scrollState );
//		}
	}
	/**
	 * 監聽移動滾動條
	 */
	@Override
	public void onScroll(AbsListView view, int firstVisibleItem,
			int visibleItemCount, int totalItemCount) {
		// 如果正在加載，就return，防止加載多次
		if(isLoading)
			return;
		// 得到listview中顯示在界面底部的id
		int lastItemid = listView.getLastVisiblePosition();
		// 如果是listview中顯示在界面底部的id=滾動條中Item總數，說明滑動到底部了，並且當前頁<=總頁數
		if((lastItemid+1) == totalItemCount && page <= maxPage){
			if(page == maxPage){//到最後一頁，提示（此方法有bug，會提示多次,，加個線程會好一點，但是還不能完全解決）
				if(!isToast){
					isToast = true;
					Toast.makeText(this, "沒有更多的數據了...", 0).show();
					new Thread(){
						@Override
						public void run() {
							// TODO Auto-generated method stub
							try {
								Thread.sleep(3000);
							} catch (InterruptedException e) {
								e.printStackTrace();
							}
							handler.sendMessage(handler.obtainMessage(0, null));
						}
					}.start();
				}
				return;
			}
			//設置正在加載中
			isLoading = true;
			if(totalItemCount > 0){
				//現在底部footer
				listView.addFooterView(footer);
				new Thread(){
					@Override
					public void run() {
						// TODO Auto-generated method stub
						try {
							Thread.sleep(1000);
						} catch (InterruptedException e) {
							// TODO Auto-generated catch block
							e.printStackTrace();
						}
						List list  = DataService.getData(pageSize, page+1);
						handler.sendMessage(handler.obtainMessage(1, list));
					}
				}.start();
			}
		}
		//System.out.println("firstVisibleItem:"+firstVisibleItem+" visibleItemCount:"+visibleItemCount+" totalItemCount:"+totalItemCount);
	}
}

MyAdapter.java

package com.example.mylistview;

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 MyAdapter extends BaseAdapter{
	
	List<Map<String,String>> list;
	
	Context context;
	
	public MyAdapter(Context context,List list){
		this.context = context;
		this.list = list;
	}
	
	@Override
	public int getCount() {
		// TODO Auto-generated method stub
		return list.size();
	}

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

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

	@Override
	public View getView(int position, View convertView, ViewGroup parent) {
		// TODO Auto-generated method stub
		ViewHolder viewHolder = new ViewHolder();
		if (convertView == null) {
			convertView = LayoutInflater.from(context).inflate(R.layout.list, null);
			viewHolder.id = (TextView) convertView.findViewById(R.id.id);
			viewHolder.name = (TextView) convertView.findViewById(R.id.name);
			viewHolder.phone = (TextView) convertView.findViewById(R.id.phone);
			convertView.setTag(viewHolder);
		}else{
			viewHolder = (ViewHolder)convertView.getTag();
		}
		// 設置應用名稱
		Map<String,String> map = list.get(position);
		viewHolder.id.setText(map.get("id"));
		viewHolder.name.setText(map.get("name"));
		viewHolder.phone.setText(map.get("phone"));
		return convertView;		
	}
	
	private static class ViewHolder { 
        public TextView id,name,phone; 
    } 
}

dataService.java

package com.example.mylistview;

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

public class DataService {

	public static List<Map<String,String>> getData(int pageSize,int page){
		List<Map<String,String>> list = new ArrayList();
		int index = (pageSize*(page-1)+1);
		int max = pageSize * page;
		for(int i = index; i <= max; i++){
			Map<String,String> map = new HashMap();
			map.put("id", "ID:"+i);
			map.put("name", "姓名:"+i);
			map.put("phone", "電話:"+i);
			list.add(map);
		}
		return list;
	}
}

源碼免費下載：http://download.csdn.net/download/qq247300948/7497127