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
1 <?xml version="1.0" encoding="utf-8"?>
2 <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
3 android:orientation="vertical"
4 android:layout_width="fill_parent"
5 android:layout_height="fill_parent"
6 >
7 <ListView
8 android:id="@id/android:list"
9 android:layout_width="match_parent"
10 android:layout_height="match_parent"
11 android:layout_weight="1"
12 android:drawSelectorOnTop="false"
13 />
14 </LinearLayout>
footer.xml
1 <?xml version="1.0" encoding="utf-8"?>
2 <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
3 android:layout_width="fill_parent"
4 android:layout_height="wrap_content"
5 android:gravity="center"
6 android:orientation="horizontal"
7 >
8 <ProgressBar
9 android:id="@+id/progressbar"
10 android:layout_width="wrap_content"
11 android:layout_height="wrap_content"
12 style="\?android:attr/progressBarStyleSmall"
13 />
14 <TextView
15 android:layout_width="wrap_content"
16 android:layout_height="wrap_content"
17 android:textSize="20.0sp"
18 android:text="正在加载..."
19 />
20 </LinearLayout>
MainActicity.xml
![复制代码]()
1 package com.szy.listview;
2
3 import android.app.ListActivity;
4 import android.os.Bundle;
5 import android.os.Handler;
6 import android.os.Message;
7 import android.view.Gravity;
8 import android.view.View;
9 import android.view.ViewGroup;
10 import android.widget.AbsListView;
11 import android.widget.BaseAdapter;
12 import android.widget.ListView;
13 import android.widget.TextView;
14
15 /**
16 *@author coolszy
17 *@date 2012-3-27
18 *@blog http://blog.92coding.com
19 */
20 public class MainActivity extends ListActivity
21 {
22 private ListView mListView;
23 private CustomAdapter mAdapter;
24 private int mScrollState;
25 private View mFooter;
26
27 @Override
28 public void onCreate(Bundle savedInstanceState)
29 {
30 super.onCreate(savedInstanceState);
31 setContentView(R.layout.main);
32
33 //获取ListView
34 mListView = getListView();
35 //根据footer.xml描述创建View
36 mFooter = getLayoutInflater().inflate(R.layout.footer, null);
37 // 在ListView底部添加正在加载视图
38 //注意：addFooterView方法需要在调用setListAdapter方法前调用！
39 mListView.addFooterView(mFooter);
40 mAdapter = new CustomAdapter();
41 setListAdapter(mAdapter);
42 //给ListView添加滚动监听器
43 mListView.setOnScrollListener(new AbsListView.OnScrollListener()
44 {
45 @Override
46 public void onScrollStateChanged(AbsListView view, int scrollState)
47 {
48 //记录当前状态
49 mScrollState = scrollState;
50 }
51
52 @Override
53 public void onScroll(AbsListView view, int firstVisibleItem, int visibleItemCount, int totalItemCount)
54 {
55 // 可视的最后一个列表项的索引
56 int lastVisibleItem = firstVisibleItem + visibleItemCount - 1;
57 //当列表正处于滑动状态且滑动到列表底部时，执行
58 if (mScrollState != AbsListView.OnScrollListener.SCROLL_STATE_IDLE
59 && lastVisibleItem == totalItemCount - 1)
60 {
61 // 执行线程，模拟睡眠5秒钟后添加10个列表项
62 new Thread()
63 {
64
65 private Handler handler = new Handler()
66 {
67
68 @Override
69 public void handleMessage(Message msg)
70 {
71 super.handleMessage(msg);
72 //增加Item数量
73 mAdapter.count += 10;
74 //通知数据集变化
75 mAdapter.notifyDataSetChanged();
76 }
77
78 };
79
80 @Override
81 public void run()
82 {
83 super.run();
84 try
85 {
86 sleep(5000);
87 handler.sendEmptyMessage(0);
88 } catch (InterruptedException e)
89 {
90 e.printStackTrace();
91 }
92 }
93
94 }.start();
95 }
96 }
97 });
98 }
99
100 private class CustomAdapter extends BaseAdapter
101 {
102 // 初始列表项数量
103 int count = 20;
104
105 @Override
106 public int getCount()
107 {
108 return count;
109 }
110
111 @Override
112 public Object getItem(int position)
113 {
114 return position;
115 }
116
117 @Override
118 public long getItemId(int position)
119 {
120 return position;
121 }
122
123 @Override
124 public View getView(int position, View convertView, ViewGroup parent)
125 {
126 TextView result = (TextView) convertView;
127 //动态创建TextView添加早ListView中
128 if (result == null)
129 {
130 result = new TextView(MainActivity.this);
131 result.setTextAppearance(MainActivity.this, android.R.style.TextAppearance_Large);
132 AbsListView.LayoutParams layoutParams = new AbsListView.LayoutParams
133 (AbsListView.LayoutParams.FILL_PARENT,
134 AbsListView.LayoutParams.WRAP_CONTENT);
135 result.setLayoutParams(layoutParams);
136 result.setGravity(Gravity.CENTER);
137 }
138 result.setText("第 " + (position + 1)+"行");
139 return result;
140 }
141 }
142 }
![复制代码]()
效果预览
![若水工作室]( "DynamicUpdateListViewDemo")
Android中动态更新ListView | 若水工作室 http://www.92coding.com/blog/index.php/archives/382.html
本文转自欢醉博客园博客，原文链接http://www.cnblogs.com/zhangs1986/p/3236531.html如需转载请自行联系原作者
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