android 滑动分页

import android.app.ListActivity;
import android.os.Bundle;
import android.os.Handler;
import android.view.Gravity;
import android.view.View;
import android.view.ViewGroup;
import android.widget.AbsListView;
import android.widget.BaseAdapter;
import android.widget.ImageView;
import android.widget.LinearLayout;
import android.widget.ProgressBar;
import android.widget.TextView;
import android.widget.AbsListView.OnScrollListener;
import android.widget.LinearLayout.LayoutParams;
public class Test extends ListActivity implements OnScrollListener {
    Aleph0 adapter = new Aleph0();
    int lastItem = 0;
    int mProgressStatus = 0;
    private Handler mHandler = new Handler();
    ProgressBar progressBar;
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
   LinearLayout searchLayout = new LinearLayout(this);
   searchLayout.setOrientation(LinearLayout.HORIZONTAL);
         progressBar = new ProgressBar(this);
         progressBar.setPadding(0, 0, 15, 0);
         searchLayout.addView(progressBar,new LinearLayout.LayoutParams(
           LinearLayout.LayoutParams.WRAP_CONTENT,
           LinearLayout.LayoutParams.WRAP_CONTENT
         ));
         TextView textView = new TextView(this);
         textView.setText("加载中...");
         textView.setGravity(Gravity.CENTER_VERTICAL);
         searchLayout.addView(textView,new LinearLayout.LayoutParams(
           LinearLayout.LayoutParams.FILL_PARENT,
           LinearLayout.LayoutParams.FILL_PARENT
         ));
         searchLayout.setGravity(Gravity.CENTER);
         LinearLayout loadingLayout = new LinearLayout(this);
         loadingLayout.addView(searchLayout,new LinearLayout.LayoutParams(
           LinearLayout.LayoutParams.WRAP_CONTENT,
           LinearLayout.LayoutParams.WRAP_CONTENT
         ));
         loadingLayout.setGravity(Gravity.CENTER);
        getListView().addFooterView(loadingLayout);
        // Start lengthy operation in a background thread
//        new Thread(new Runnable() {
//            public void run() {
//                while (mProgressStatus < 100) {
//
//                    // Update the progress bar
//                    mHandler.post(new Runnable() {
//                        public void run() {
//                        progressBar.setProgress(mProgressStatus);
//                        }
//                    });
//                }
//            }
//        }).start();
        registerForContextMenu(getListView());
        setListAdapter(adapter);
        getListView().setOnScrollListener(this);
    }
    public void onScroll(AbsListView v, int firstVisibleItem, int visibleItemCount, int totalItemCount) {
        lastItem = firstVisibleItem + visibleItemCount - 1 ;
        System.out.println("lastItem:" + lastItem);
    }
    public void onScrollStateChanged(AbsListView v, int state) {
    if(lastItem == adapter.count && state == OnScrollListener.SCROLL_STATE_IDLE){
          adapter.count += 10;
          adapter.notifyDataSetChanged();
    }
//        if(state == OnScrollListener.SCROLL_STATE_IDLE ) {
//                adapter.count += 10;
//                adapter.notifyDataSetChanged();
//        }
    }
    class Aleph0 extends BaseAdapter {
        int count = 10;
        public int getCount() { return count; }
        public Object getItem(int pos) { return pos; }
        public long getItemId(int pos) { return pos; }
        public View getView(int pos, View v, ViewGroup p) {
                TextView view = new TextView(Test.this);
                view.setText("entry " + pos);
                view.setHeight(90);
                return view;
        }
    }
}

OnScrollListener回调分析

如果adapter中的数据量很大的时候，在加载listview时会出现卡顿的现象。这是会让用户抓狂！最好的解决办法就是先加载一定数量的数据，然后在最下方提示正在加载！
动态加载就是把放入adapter中的数据分好几次加载。在用户拖动listview时再加载一定的数据，和sina微博的客户端类似。
给listview添加OnScrollListener监听事件默认会覆盖下面两个方法：

new OnScrollListener() {   
        boolean isLastRow = false;            
        @Override   
        public void onScroll(AbsListView view, int firstVisibleItem, int visibleItemCount, int totalItemCount) {   
            //滚动时一直回调，直到停止滚动时才停止回调。单击时回调一次。   
            //firstVisibleItem：当前能看见的第一个列表项ID（从0开始）   
            //visibleItemCount：当前能看见的列表项个数（小半个也算）   
            //totalItemCount：列表项共数            
            //判断是否滚到最后一行   
            if (firstVisibleItem + visibleItemCount == totalItemCount && totalItemCount > 0) {   
                isLastRow = true;   
            }   
        }   
        @Override   
        public void onScrollStateChanged(AbsListView view, int scrollState) {   
            //正在滚动时回调，回调2-3次，手指没抛则回调2次。scrollState = 2的这次不回调   
            //回调顺序如下   
            //第1次：scrollState = SCROLL_STATE_TOUCH_SCROLL(1) 正在滚动   
            //第2次：scrollState = SCROLL_STATE_FLING(2) 手指做了抛的动作（手指离开屏幕前，用力滑了一下）   
            //第3次：scrollState = SCROLL_STATE_IDLE(0) 停止滚动                         

             //当屏幕停止滚动时为0；当屏幕滚动且用户使用的触碰或手指还在屏幕上时为1； 
            //由于用户的操作，屏幕产生惯性滑动时为2 
       
            //当滚到最后一行且停止滚动时，执行加载   
            if (isLastRow && scrollState == AbsListView.OnScrollListener.SCROLL_STATE_IDLE) {   
                //加载元素   
                ......            
                isLastRow = false;   
            }   
        }   
    }