32-listview分批加载

/datapageload/res/layout/main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:orientation="vertical" >

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

</LinearLayout>

/datapageload/res/layout/listview_item.xml

<?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:layout_width="match_parent"
    android:layout_height="match_parent"
    android:textSize="18sp"
    android:textColor="#FFFFFF"
        android:id="@+id/textView"
        />

</LinearLayout>

/datapageload/src/cn/itcast/pageload/MainActivity.java 

package cn.itcast.pageload;

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

import cn.itcast.service.DataService;

import android.app.Activity;
import android.os.Bundle;
import android.os.Handler;
import android.os.Message;
import android.util.Log;
import android.view.View;
import android.widget.AbsListView;
import android.widget.AbsListView.OnScrollListener;
import android.widget.ArrayAdapter;
import android.widget.ListView;

public class MainActivity extends Activity {
    private ListView listView;
    private List<String> data = new ArrayList<String>();
    ArrayAdapter<String> adapter;
    View footer;
    
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        
        footer = getLayoutInflater().inflate(R.layout.footer, null);
        
        listView = (ListView) this.findViewById(R.id.listView);
        listView.setOnScrollListener(new ScrollListener());
        
        data.addAll(DataService.getData(0, 20));        
        adapter = new ArrayAdapter<String>(this, R.layout.listview_item, R.id.textView, data);
        listView.addFooterView(footer);//添加页脚(放在ListView最后) 要在设置适配器之前添加，才能包装到适配器
        listView.setAdapter(adapter);
        listView.removeFooterView(footer);//设置到适配器就可以删除
    }
    
    private int number = 20;//每次获取多少条数据
    private int maxpage = 5;//总共有多少页
    private boolean loadfinish = true;
    private final class ScrollListener implements OnScrollListener{
		public void onScrollStateChanged(AbsListView view, int scrollState) {
			Log.i("MainActivity", "onScrollStateChanged(scrollState="+ scrollState+ ")");
		}
		/*firstVisibleItem第一个条目 visibleItemCount可见的条目 totalItemCount当前总条数
		 正在滚动的时候就会调用onScroll
		*/
		public void onScroll(AbsListView view, int firstVisibleItem, int visibleItemCount, int totalItemCount) {
			Log.i("MainActivity", "onScroll(firstVisibleItem="+ firstVisibleItem+ ",visibleItemCount="+
					visibleItemCount+ ",totalItemCount="+ totalItemCount+ ")");
			
			final int loadtotal = totalItemCount;
			int lastItemid = listView.getLastVisiblePosition();//获取当前屏幕最后Item的ID
			if((lastItemid+1) == totalItemCount){//达到数据的最后一条记录
				if(totalItemCount > 0){//不然取模出问题
					//当前页
					int currentpage = totalItemCount%number == 0 ? totalItemCount/number : totalItemCount/number+1;
					int nextpage = currentpage + 1;//下一页
					if(nextpage <= maxpage && loadfinish){
						loadfinish = false;
						listView.addFooterView(footer);
						
						new Thread(new Runnable() {						
							public void run() {
								try {
									Thread.sleep(3000);
								} catch (InterruptedException e) {
									e.printStackTrace();
								}
								List<String> result = DataService.getData(loadtotal, number);
								handler.sendMessage(handler.obtainMessage(100, result));//100是id随便写
							}
						}).start();
					}		
				}
						
			}
		}
    }
    
    Handler handler = new Handler(){
		public void handleMessage(Message msg) {
			data.addAll((List<String>) msg.obj);
			adapter.notifyDataSetChanged();//告诉ListView数据已经发生改变，要求ListView更新界面显示
			if(listView.getFooterViewsCount() > 0) listView.removeFooterView(footer);//有页脚则删除
			loadfinish = true;
		}    	
    };
    
}

/datapageload/src/cn/itcast/service/DataService.java

package cn.itcast.service;

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

public class DataService {

	public static List<String> getData(int offset, int maxResult){//分页 limit 0,20
		List<String> data = new ArrayList<String>();
		for(int i=0 ; i < 20 ; i++){
			data.add("ListView数据的分批加载"+ i);
		}
		return data;
	}
}

/datapageload/res/layout/footer.xml

<?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="horizontal" >

    <ProgressBar android:id="@+id/c81_forthBar"
        android:layout_width="50dp"
    	android:layout_height="wrap_content"
         style="?android:attr/progressBarStyle" /> 
    <TextView android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:gravity="center_vertical"
    android:textSize="20sp"
    android:text="数据正在加载..."
    />
</LinearLayout>