Android ListView 获取网络上的数据，动态地进行数据更新！

将数据动态地更新ListView中，搞了两个小时，终于搞定了，感谢 txlong_onz，文章地址：http://txlong-onz.iteye.com/blog/947620。

以下代码是怎么实现动态更新ListView的方法。

package com.photographic.ui;

import java.util.List;

import com.photographic.adapter.PhotographicStudioListViewAdapter;

import com.photographic.bean.PhotographicStudioListItemBean;

import com.photographic.control.CityListDialog;

import com.photographic.service.WebServiceData;

import android.app.Activity;

import android.content.Intent;

import android.os.Bundle;

import android.os.Handler;

import android.os.Message;

import android.util.Log;

import android.view.Gravity;

import android.view.View;

import android.view.View.OnClickListener;

import android.widget.AdapterView;

import android.widget.AdapterView.OnItemClickListener;

import android.widget.Button;

import android.widget.LinearLayout;

import android.widget.LinearLayout.LayoutParams;

import android.widget.AbsListView;

import android.widget.ListView;

import android.widget.ProgressBar;

import android.widget.TextView;

import android.widget.Toast;

public class PhotographicStudioList extends Activity implements AbsListView.OnScrollListener{

public static final String TAG = "PhotographicList";

private WebServiceData wsd;

public ListView listView;

public TextView photoStudioName;

private PhotographicStudioListViewAdapter adapter;

private LinearLayout loadingLayout;

private Thread loadWebDataThread;

public List<PhotographicStudioListItemBean> itemInfoList;

private List<PhotographicStudioListItemBean> itemInfoListTemp;

// private boolean refreshable;

/**

* 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;



private static int network_error = 0;

/** Called when the activity is first created. */

@Override

public void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.pslist_ui);



initProgressBarPosition();



Button button = (Button)findViewById(R.id.button01);

button.setOnClickListener(new OnClickListener()

{

public void onClick(View v)

{

if (network_error == 1)

{

Toast.makeText(PhotographicStudioList.this, "无法切换城市，原因是获取不到网络上的数据！", Toast.LENGTH_SHORT).show();

}

else

{

new CityListDialog(PhotographicStudioList.this).showCityListDialog();

}

}

});



// 获取ListView对象

listView = (ListView)findViewById(R.id.listview_01);

// 初始化时加载广东省广州市的影楼

wsd = new WebServiceData();

try

{

itemInfoList = wsd.getPhotoStudioListInformation(getCityId(), 1);

adapter = new PhotographicStudioListViewAdapter(this, itemInfoList);

}

catch (Exception e1)

{

network_error = 1;

Toast.makeText(this, "加载网络数据失败", Toast.LENGTH_SHORT).show();

return;

}

listView.addFooterView(loadingLayout);
// 添加到脚页显示

photoStudioName = (TextView)findViewById(R.id.textview_01);

photoStudioName.setText("广州市影楼列表");

listView.setAdapter(adapter);
// 给ListView添加适配器

listView.setOnScrollListener(this);

listView.setOnItemClickListener(new OnItemClickListener()

{

public void onItemClick(AdapterView<?> arg0, View arg1, int arg2,

long arg3)

{

Log.i(TAG, "success");

// 通过影楼列表的PhotoStudioID属性获得该公司的简介

Intent intent = new Intent(PhotographicStudioList.this, PhotographicStudioAbout.class);

startActivity(intent);

}

});

}



/**

* 初始化进度条

*/

private void initProgressBarPosition() {

// 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(250, 15, 15, 15);

// 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);

}

/**

* 滑动状态改变时调用

*/

public void onScrollStateChanged(AbsListView view, int scrollState)

{}

/**

* 滑动时被调用

*/

public void onScroll(AbsListView view, int firstVisibleItem,

int visibleItemCount, int totalItemCount)

{

Log.i(TAG, firstVisibleItem + visibleItemCount + "=" + totalItemCount);

if (firstVisibleItem + visibleItemCount == totalItemCount)

{

// 开线程去下载网络数据

if (loadWebDataThread == null || !loadWebDataThread.isAlive())

{

loadWebDataThread = new Thread()

{

@Override

public void run()

{

// Log.i(TAG, "enter");

//
Log.i(TAG, getCityId() + "");

//
Log.i(TAG, "" + bean.getTotalNumber());

int totalNum = wsd.getNumber(getCityId(), 1) + 1;

if (adapter.getCount() <= totalNum + 1)

{

int count = adapter.getCount() + 6;

int currentPage = count / 6;

//
Log.i(TAG, "currentPage=" + currentPage);

try

{

itemInfoListTemp = wsd.getPhotoStudioListInformation(getCityId(), currentPage);

}

catch (Exception e)

{

e.printStackTrace();

}

}

else

{

listView.removeFooterView(loadingLayout);

}



try

{

// 这里是网络数据请求的方法，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);

}

};

loadWebDataThread.start();

}

}

}



private Handler handler = new Handler()

{

@Override

public void handleMessage(Message msg)

{

switch (msg.what)

{

case 1:

if (itemInfoListTemp != null)

{

itemInfoList.addAll(itemInfoListTemp);

adapter.notifyDataSetChanged();

itemInfoListTemp = null;

}

break;

default:

break;

}

}

};



/**

* 获得城市Id,默认为293

* @return

*/

private int getCityId()

{

int cityId = CityListDialog.cityId;

if (cityId == 0)

{

return 293;

}

return cityId;

}

}

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package com.photographic.adapter;

import java.util.List;

import com.photographic.bean.PhotographicStudioListItemBean;

import com.photographic.ui.R;

import android.app.Activity;

import android.content.Context;

import android.util.Log;

import android.view.LayoutInflater;

import android.view.View;

import android.view.ViewGroup;

import android.widget.BaseAdapter;

import android.widget.TextView;

/**

* 为影楼列表界面里的ListView自定义适配器

* @author Treasure

*

*/

public class PhotographicStudioListViewAdapter extends BaseAdapter

{

public static final String TAG = "PhotographicStudioListViewAdapter";

public List<PhotographicStudioListItemBean> itemListData;

public Activity context;

public LayoutInflater inflater;

/**

* 带参数的构造方法

* @param context
上下文

* @param itemListData
放置列表里面的数据项

*/

public PhotographicStudioListViewAdapter(Activity context,

List<PhotographicStudioListItemBean> itemListData)

{

super();

this.context = context;

this.itemListData = itemListData;

this.inflater = (LayoutInflater)context.getSystemService(

Context.LAYOUT_INFLATER_SERVICE);

}

public int getCount()

{

return itemListData.size();

}

public Object getItem(int position)

{

return itemListData.get(position);

}

public long getItemId(int position)

{

return 0;

}

public View getView(int position, View convertView, ViewGroup parent)

{

WidgetInListView widget;

if (convertView == null)

{

// 初始化ListView里面的widget

widget = new WidgetInListView();

// 用资源布局填充ListView控件

convertView = inflater.inflate(R.layout.listview_content, null);

// widget.logoImg = (ImageView)convertView.findViewById(R.id.imageview_01);

widget.photoStudioNameTxt = (TextView)convertView.findViewById(R.id.textview_02);

widget.telephoneTxt = (TextView)convertView.findViewById(R.id.textview_03);

widget.addressTxt = (TextView)convertView.findViewById(R.id.textview_04);

widget.themePhotoCountTxt = (TextView)convertView.findViewById(R.id.textview_05);

widget.priceSetCountTxt = (TextView)convertView.findViewById(R.id.textview_06);

convertView.setTag(widget);

}

else

{

widget = (WidgetInListView)convertView.getTag();

}

// 向ListView里添加数据

PhotographicStudioListItemBean itemBean = (PhotographicStudioListItemBean) itemListData

.get(position);

// widget.logoImg.setImageBitmap(itemBean.getLogo());

widget.photoStudioNameTxt.setText(showSubString(itemBean.getPhotoStudioName(), 1));

widget.telephoneTxt.setText(showSubString(itemBean.getTelephone(), 2));

widget.addressTxt.setText(showSubString(itemBean.getAddress(), 3));

widget.themePhotoCountTxt.setText("样片" + itemBean.getThemePhoto());

widget.priceSetCountTxt.setText("套系" + itemBean.getPriceSet());

return convertView;

}

/**

* 内部类，将该类里面的控件加入到ListView中

* @author Treasure

*/

private class WidgetInListView

{

// ImageView logoImg;

TextView photoStudioNameTxt;

TextView telephoneTxt;

TextView addressTxt;

TextView themePhotoCountTxt;

TextView priceSetCountTxt;

}

/**

* 为了使影楼列表界面排版友好，所以对于很长的字符串进行截取

* @param itemBean

* @param select

* @return

*/

private String showSubString(String data, int select)

{

String str = null;

switch (select)

{

case 1:

// 影楼名 汉字12个

str = cutString(data, 24);

break;

case 2:

// 电话号码 数字12个

str = cutString(data, 13);

break;

case 3:

// 地址 汉字17个

str = cutString(data, 34);

break;

}

return str;

}

/**

* 汉字

* 数字

* @param data

* @return

*/

// private int exactLength(String data)

// {

// int length = 0;

// for (int i = 0; i < data.length(); i++)

// {

// if (data.charAt(i) > 255)

// {

// length += 2;

// }

// else

// {

// length += 1;

// }

// }

// Log.i(TAG, length + "");

// return length;

// }

/**

* 截取合适的长度

* @param data

* @param num

* @return

*/

private String cutString(String data, int num)

{

int len = data.length();
// 原始数据的长度

StringBuffer sb = new StringBuffer();

int length = 0;
// 累加长度，不能大于传入的值

// String[] str = new String[len];
// 创建字符串数组，用于存放传入数据的值。

for (int i = 0; i < len; i++)

{

if (length > num)

{

return sb.append("...").toString();

}

else

{

char ch = data.charAt(i);

if (ch > 255)

{

length += 2;

sb.append(ch);

}

else

{

length += 1;

sb.append(ch);

}

}

}

return sb.toString();

}

}

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package com.photographic.bean;

import android.graphics.Bitmap;

/**

* 影楼列表界面中的 ListView 控件里面的 get(),set() 方法

* @author Treasure

*/

public class PhotographicStudioListItemBean

{

// private Bitmap logo;

private String photoStudioName;

private String telephone;

private String address;

private String themePhoto;

private String priceSet;

// public Bitmap getLogo()

// {

// return logo;

// }

//

// public void setLogo(Bitmap logo)

// {

// this.logo = logo;

// }

public String getPhotoStudioName()

{

return photoStudioName;

}

public void setPhotoStudioName(String photoStudioName)

{

this.photoStudioName = photoStudioName;

}

public String getTelephone()

{

return telephone;

}

public void setTelephone(String telephone)

{

this.telephone = telephone;

}

public String getAddress()

{

return address;

}

public void setAddress(String address)

{

this.address = address;

}

public String getThemePhoto()

{

return themePhoto;

}

public void setThemePhoto(String themePhoto)

{

this.themePhoto = themePhoto;

}

public String getPriceSet()

{

return priceSet;

}

public void setPriceSet(String priceSet)

{

this.priceSet = priceSet;

}

}

解决的思路是：定义两个List<PhotographicStudioListItemBean>，一个用于“存放所有的数据”，一个用于“存放动态加载的数据”。对于notifyDataSetChanged()方法的理解是，只对“存放所有数据”的List<PhotographicStudioListItemBean>生效。因为它创建了自定义适配器的对象，并将“存放所有数据”的List<PhotographicStudioListItemBean>加入到适配器中。对于为什么给其它的List<PhotographicStudioListItemBean>，并创建了自定义适配器对象不管用。这个问题我无法解答，但是，大概的原理我懂。只可意会不可言传。