Android中使用Listview动态加载数据
listview 是android网络开发中经常使用的一种控件，像现在的人人网、微博等等android客户端，都在使用它，但是大家不难发现其在加载数据的过程中不是一次性加载完，而是没等你看过固定条数据后再继续加载，这样对于需要加载的大量数据；来说分开进行，客户体验比较好。一下是listview实现动态加载数据的方法。只是一个简单的框架。（转自于网络）
import
android.app.Activity;
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.LinearLayout;
import
android.widget.ListView;
import
android.widget.ProgressBar;
import
android.widget.TextView;
import
android.widget.Toast;
import
android.widget.AbsListView.OnScrollListener;
import
android.widget.LinearLayout.LayoutParams;
public
class
ListViewForLoading extends
Activity implements
OnScrollListener {
private
listViewAdapter adapter = new
listViewAdapter();
ListView listView;
LinearLayout loadingLayout;
private
Thread mThread;
/**
* 设置布局显示属性
*/
private
LayoutParams mLayoutParams = new
LinearLayout.LayoutParams(
LinearLayout.LayoutParams.WRAP_CONTENT,
LinearLayout.LayoutParams.WRAP_CONTENT);
/**
* 设置布局显示目标最大化属性
*/
private
LayoutParams FFlayoutParams = new
LinearLayout.LayoutParams(
LinearLayout.LayoutParams.FILL_PARENT,
LinearLayout.LayoutParams.FILL_PARENT);
private
ProgressBar progressBar;
/** Called when the activity is first created. */
@Override
public
void
onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
init();
}
private
void
init() {
// TODO Auto-generated method stub
// 线性布局
LinearLayout layout = new
LinearLayout(this);
// 设置布局 水平方向
layout.setOrientation(LinearLayout.HORIZONTAL);
// 进度条
progressBar = new
ProgressBar(this);
// 进度条显示位置
progressBar.setPadding(0, 0, 15, 0);
// 把进度条加入到layout中
layout.addView(progressBar, mLayoutParams);
// 文本内容
TextView textView = new
TextView(this);
textView.setText("加载中...");
textView.setGravity(Gravity.CENTER_VERTICAL);
// 把文本加入到layout中
layout.addView(textView, FFlayoutParams);
// 设置layout的重力方向，即对齐方式是
layout.setGravity(Gravity.CENTER);
// 设置ListView的页脚layout
loadingLayout = new
LinearLayout(this);
loadingLayout.addView(layout, mLayoutParams);
loadingLayout.setGravity(Gravity.CENTER);
// 得到一个ListView用来显示条目
listView = (ListView) findViewById(R.id.tv);
// 添加到脚页显示
listView.addFooterView(loadingLayout);
// 给ListView添加适配器
listView.setAdapter(adapter);
// 给ListView注册滚动监听
listView.setOnScrollListener(this);
}
/**
* 要用用于生成显示数据
*
* @author huangbq
*
*/
class
listViewAdapter 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;
if
(v == null) {
view = new
TextView(ListViewForLoading.this);
} else
{
view = (TextView) v;
}
view.setText("ListItem "
+ pos);
view.setTextSize(20f);
view.setGravity(Gravity.CENTER);
view.setHeight(60);
return
view;
}
}
@Override
public
void
onScroll(AbsListView view, int
firstVisibleItem,
int
visibleItemCount, int
totalItemCount) {
// TODO Auto-generated method stub
if(firstVisibleItem+visibleItemCount==totalItemCount)
{
//开线程去下载网络数据
if
(mThread == null
|| !mThread.isAlive()) {
mThread = new
Thread() {
@Override
public
void
run() {
try
{
//这里放你网络数据请求的方法，我在这里用线程休眠5秒方法来处理
Thread.sleep(5000);
} catch
(InterruptedException e) {
e.printStackTrace();
}
Message message = new
Message();
message.what = 1;
handler.sendMessage(message);
}
};
mThread.start();
}
}
}
@Override
public
void
onScrollStateChanged(AbsListView view, int
scrollState) {
// TODO Auto-generated method stub
}
private
Handler handler = new
Handler() {
@Override
public
void
handleMessage(Message msg) {
// TODO Auto-generated method stub
switch
(msg.what) {
case
1:
if
(adapter.count <= 41) {
adapter.count += 10;
int
currentPage = adapter.count / 10;
Toast.makeText(getApplicationContext(),"第"
+ currentPage + "页", Toast.LENGTH_LONG).show();
} else
{
listView.removeFooterView(loadingLayout);
}
//重新刷新Listview的adapter里面数据
adapter.notifyDataSetChanged();
break;
default:
break;
}
}
};
}
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程序运行结果：