Android中动态更新ListView（转）

在使用ListView时，会遇到当ListView列表滑动到最底端时，添加新的列表项的问题，本文通过代码演示如何动态的添加新的列表项到ListView中。
实现步骤：调用ListView的setOnScrollListener()方法设置滑动监听器，实现OnScrollListener接口的方法，判断当列表滑动到最低端时，加载新的列表项。
其中OnScrollListener接口需要实现如下两个方法：
onScroll(AbsListView view, int firstVisibleItem, int visibleItemCount, int totalItemCount)
view 报告滑动状态的视图
firstVisibleItem 可视的第一个列表项的索引
visibleItemCount 可视的列表项个数
totalItemCount 总共的列表项个数
onScrollStateChanged(AbsListView view, int scrollState)
view 报告滑动状态的视图
scrollState 滑动状态
滑动状态包括
SCROLL_STATE_IDLE : 0  视图没有滑动
SCROLL_STATE_TOUCH_SCROLL : 1  用户正在触摸滑动，手指仍在屏幕上
SCROLL_STATE_FLING : 2  用户之前触摸滑动，现在正在滑行，直到停止
下面通过代码给大家演示效果
main.xml

 <?xml version="1.0" encoding="utf-8"?>
 <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
     android:orientation="vertical"
     android:layout_width="fill_parent"
     android:layout_height="fill_parent"
     >
     <ListView
         android:id="@id/android:list"
         android:layout_width="match_parent"
         android:layout_height="match_parent"
         android:layout_weight="1"
         android:drawSelectorOnTop="false"
         />
 </LinearLayout>

footer.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="wrap_content"
     android:gravity="center"
     android:orientation="horizontal"
     >
     <ProgressBar
         android:id="@+id/progressbar"
         android:layout_width="wrap_content"
         android:layout_height="wrap_content"
         style="\?android:attr/progressBarStyleSmall"
         />
     <TextView
         android:layout_width="wrap_content"
         android:layout_height="wrap_content"
         android:textSize="20.0sp"
         android:text="正在加载..."
         />
 </LinearLayout>

MainActicity.xml

 package com.szy.listview;

 import android.app.ListActivity;
 import android.os.Bundle;
 import android.os.Handler;
 import android.os.Message;
 import android.view.Gravity;
 import android.view.View;
 import android.view.ViewGroup;
 import android.widget.AbsListView;
 import android.widget.BaseAdapter;
 import android.widget.ListView;
 import android.widget.TextView;

 /**
  *@author coolszy
  *@date 2012-3-27
  *@blog http://blog.92coding.com
  */
 public class MainActivity extends ListActivity
 {
     private ListView mListView;
     private CustomAdapter mAdapter;
     private int mScrollState;
     private View mFooter;

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

         //获取ListView
         mListView = getListView();
         //根据footer.xml描述创建View
         mFooter = getLayoutInflater().inflate(R.layout.footer, null);
         // 在ListView底部添加正在加载视图
         //注意：addFooterView方法需要在调用setListAdapter方法前调用！
         mListView.addFooterView(mFooter);
         mAdapter = new CustomAdapter();
         setListAdapter(mAdapter);
         //给ListView添加滚动监听器
         mListView.setOnScrollListener(new AbsListView.OnScrollListener()
         {
             @Override
             public void onScrollStateChanged(AbsListView view, int scrollState)
             {
                 //记录当前状态
                 mScrollState = scrollState;
             }

             @Override
             public void onScroll(AbsListView view, int firstVisibleItem, int visibleItemCount, int totalItemCount)
             {
                 // 可视的最后一个列表项的索引
                 int lastVisibleItem = firstVisibleItem + visibleItemCount - 1;
                 //当列表正处于滑动状态且滑动到列表底部时，执行
                 if (mScrollState != AbsListView.OnScrollListener.SCROLL_STATE_IDLE
                     && lastVisibleItem == totalItemCount - 1)
                 {
                     // 执行线程，模拟睡眠5秒钟后添加10个列表项
                     new Thread()
                     {

                         private Handler handler = new Handler()
                         {

                             @Override
                             public void handleMessage(Message msg)
                             {
                                 super.handleMessage(msg);
                                 //增加Item数量
                                 mAdapter.count += 10;
                                 //通知数据集变化
                                 mAdapter.notifyDataSetChanged();
                             }

                         };

                         @Override
                         public void run()
                         {
                             super.run();
                             try
                             {
                                 sleep(5000);
                                 handler.sendEmptyMessage(0);
                             } catch (InterruptedException e)
                             {
                                 e.printStackTrace();
                             }
                         }

                     }.start();
                 }
             }
         });
     }

     private class CustomAdapter extends BaseAdapter
     {
         // 初始列表项数量
         int count = 20; 

         @Override
         public int getCount()
         {
             return count;
         }

         @Override
         public Object getItem(int position)
         {
             return position;
         }

         @Override
         public long getItemId(int position)
         {
             return position;
         }

         @Override
         public View getView(int position, View convertView, ViewGroup parent)
         {
             TextView result = (TextView) convertView;
             //动态创建TextView添加早ListView中
             if (result == null)
             {
                 result = new TextView(MainActivity.this);
                 result.setTextAppearance(MainActivity.this, android.R.style.TextAppearance_Large);
                 AbsListView.LayoutParams layoutParams = new AbsListView.LayoutParams
                                                         (AbsListView.LayoutParams.FILL_PARENT,
                                                         AbsListView.LayoutParams.WRAP_CONTENT);
                 result.setLayoutParams(layoutParams);
                 result.setGravity(Gravity.CENTER);
             }
             result.setText("第 " + (position + 1)+"行");
             return result;
         }
     }
 }

效果预览

Android中动态更新ListView | 若水工作室 http://www.92coding.com/blog/index.php/archives/382.html