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