Android中ListView异步加载数据

1.主Activity

 public class MainActivity extends Activity {

     private ListView listView;
     private ArrayList<Person> persons;
     private ListAdapter adapter;
     private Handler handler=null;
     //xml文件的网络地址
     final String path="http://192.168.5.10:8080/FileServer/person.xml";
     @SuppressLint("HandlerLeak")
     protected void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
         setContentView(R.layout.main);

         listView=(ListView) super.findViewById(R.id.listview);
         //cache=new File(Environment.getExternalStorageDirectory().getAbsolutePath()+"/cache");

         //开一条子线程加载网络数据
         Runnable runnable=new Runnable()
         {
             public void run()
             {
                 try
                 {
                     Thread.sleep(2000);
                     //xmlwebData解析网络中xml中的数据
                     persons=XmlwebData.getData(path);
                     //发送消息，并把persons结合对象传递过去
                     handler.sendMessage(handler.obtainMessage(0, persons));
                 }
                 catch (InterruptedException e)
                 {
                     e.printStackTrace();
                 }
             }
         };

         try
         {
             //开启线程
             new Thread(runnable).start();
             //handler与线程之间的通信及数据处理
             handler=new Handler()
             {
                 public void handleMessage(Message msg)
                 {
                     if(msg.what==0)
                     {
                         //msg.obj是获取handler发送信息传来的数据
                         @SuppressWarnings("unchecked")
                         ArrayList<Person> person=(ArrayList<Person>) msg.obj;
                         //给ListView绑定数据
                         BinderListData(person);
                     }
                 }
             };
         }
         catch (Exception e)
         {
             e.printStackTrace();
         }
     }

     //绑定数据
     public void BinderListData(ArrayList<Person> person)
     {
         //创建adapter对象
         adapter=new ListViewAdapter(R.layout.item,this,person);
         //将Adapter绑定到listview中
         listView.setAdapter(adapter);
     }

 }

2.从网络中获取xml文件并解析数据

 public class XmlwebData
 {
     private static ArrayList<Person> persons=null;     public static ArrayList<Person> getData(final String path)
     {
                 try
                 {
                     URL url=new URL(path);
                     Person person=null;
                     HttpURLConnection conn=(HttpURLConnection) url.openConnection();
                     conn.setRequestMethod("GET");
                     conn.setConnectTimeout(5000);
                     if(conn.getResponseCode()==200)
                     {
                         InputStream inputstream=conn.getInputStream();
                         XmlPullParser xml=Xml.newPullParser();
                         xml.setInput(inputstream, "UTF-8");
                         int event=xml.getEventType();

                         while(event!=XmlPullParser.END_DOCUMENT)
                         {
                             switch (event)
                             {
                             //开始解析文档
                             case XmlPullParser.START_DOCUMENT:
                                 persons=new ArrayList<Person>();
                                 break;
                             case XmlPullParser.START_TAG:

                                 String value=xml.getName();
                                 if(value.equals("person"))
                                 {//person对象的初始化必须在这里初始化不然可能出现为null的现象
                                     person=new Person();
                                     //获取属性值
                                     person.setId(new Integer(xml.getAttributeValue(0)));
                                 }
                                 else if(value.equals("name"))
                                 {
                                     person.setName(xml.nextText());
                                 }
                                 else if(value.equals("sex"))
                                 {
                                     person.setSex(xml.nextText());
                                 }
                                 else if(value.equals("age"))
                                 {
                                     person.setAge(new Integer(xml.nextText()));
                                 }
                                 else if(value.equals("path"))
                                 {
                                     person.setPath(xml.nextText());
                                 }
                                 break;
                             case XmlPullParser.END_TAG:
                                 if(xml.getName().equals("person"))
                                 {
                                     persons.add(person);
                                     System.out.println(person.getName());;
                                     person=null;
                                 }
                                 break;
                             }
                             //解析下一个对象
                             event=xml.next();
                         }
                         return persons;
                     }
                 }
                 catch (Exception e)
                 {
                     e.printStackTrace();
                 } 

         return null;

     }

 }

3.Person对象类

 public class Person
 {
     private int id;
     private String name;
     private String sex;
     private String path;
     public String getPath() {
         return path;
     }
     public void setPath(String path) {
         this.path = path;
     }
     private int age;
     public int getId() {
         return id;
     }
     public void setId(int id) {
         this.id = id;
     }
     public String getName() {
         return name;
     }
     public void setName(String name) {
         this.name = name;
     }
     public String getSex() {
         return sex;
     }
     public void setSex(String sex) {
         this.sex = sex;
     }
     public int getAge() {
         return age;
     }
     public void setAge(int age) {
         this.age = age;
     }
     public Person(){

     }
 }

4.Adapter数据适配器类

 public class ListViewAdapter extends BaseAdapter implements ListAdapter
 {

     private ArrayList<Person> data;
     private int id;
     private Context context;
     private LayoutInflater inflater;
     public ListViewAdapter(int item, MainActivity mainActivity,ArrayList<Person> data)
     {
         this.data=data;
         this.context=mainActivity;
         this.id=item;
         inflater=LayoutInflater.from(context);
     }

     @Override
     public int getCount()
     {
         return data.size();
     }

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

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

     @Override
     public View getView(int position, View view, ViewGroup arg2)
     {
         TextView name=null;
         TextView sex=null;
         TextView age=null;
         ImageView img=null;
         if(view==null)
         {
             view=inflater.inflate(id, null);
             name=(TextView) view.findViewById(R.id.PersonName);
             sex=(TextView) view.findViewById(R.id.PersonSex);
             age=(TextView) view.findViewById(R.id.PersonAge);
             img=(ImageView) view.findViewById(R.id.Personimage);
             //保存view对象到ObjectClass类中
             view.setTag(new ObjectClass(name,sex,age,img));
         }
         else
         {
             //得到保存的对象
             ObjectClass objectclass=(ObjectClass) view.getTag();
             name=objectclass.name;
             sex=objectclass.sex;
             age=objectclass.age;
             img=objectclass.img;
         }

         Person person=(Person) data.get(position);
         //帮数据绑定到控件上
         name.setText(person.getName().toString());
         sex.setText("性别："+person.getSex().toString());
         age.setText("年龄："+String.valueOf(person.getAge()));
         //加载图片资源
         LoadImage(img,person.getPath());
         return view;

     }

     private void LoadImage(ImageView img, String path)
     {
         //异步加载图片资源
         AsyncTaskImageLoad async=new AsyncTaskImageLoad(img);
         //执行异步加载，并把图片的路径传送过去
         async.execute(path);

     }

     private final class ObjectClass
     {
         TextView name=null;
         TextView sex=null;
         TextView age=null;
         ImageView img=null;
         public ObjectClass(TextView name, TextView sex, TextView age,ImageView img)
         {
             this.name=name;
             this.sex=sex;
             this.age=age;
             this.img=img;
         }
     }

 }

5.异步加载图片类

 public class AsyncTaskImageLoad extends AsyncTask<String, Integer, Bitmap> {

     private ImageView Image=null;

     public AsyncTaskImageLoad(ImageView img)
     {
         Image=img;
     }
     //运行在子线程中
     protected Bitmap doInBackground(String... params) {
         try
         {
             URL url=new URL(params[0]);
             HttpURLConnection conn=(HttpURLConnection) url.openConnection();
             conn.setRequestMethod("POST");
             conn.setConnectTimeout(5000);
             if(conn.getResponseCode()==200)
             {
                 InputStream input=conn.getInputStream();
                 Bitmap map=BitmapFactory.decodeStream(input);
                 return map;
             }
         } catch (Exception e)
         {
             e.printStackTrace();
         }
         return null;
     }

     protected void onPostExecute(Bitmap result)
     {
         if(Image!=null && result!=null)
         {
             Image.setImageBitmap(result);
         }

         super.onPostExecute(result);
     }
 }

6.网络中的person.xml文件内容为

 <?xml version="1.0" encoding="UTF-8"?>
 <Persons>
     <person id="1">
         <name>张三</name>
         <sex>男</sex>
         <age>25</age>
         <path>http://192.168.5.10:8080/FileServer/chengjisihan.jpg</path>
     </person>
     <person id="2">
         <name>李斯</name>
         <sex>男</sex>
         <age>78</age>
         <path>http://192.168.5.10:8080/FileServer/laozi.jpg</path>
     </person>
     <person id="3">
         <name>王五</name>
         <sex>男</sex>
         <age>22</age>
         <path>http://192.168.5.10:8080/FileServer/lilongji.jpg</path>
     </person>
     <person id="4">
         <name>庞聪</name>
         <sex>男</sex>
         <age>31</age>
         <path>http://192.168.5.10:8080/FileServer/lishimin.jpg</path>
     </person>
     <person id="5">
         <name>孙膑</name>
         <sex>男</sex>
         <age>48</age>
         <path>http://192.168.5.10:8080/FileServer/lisi.jpg</path>
     </person>
     <person id="6">
         <name>孙武</name>
         <sex>男</sex>
         <age>58</age>
         <path>http://192.168.5.10:8080/FileServer/liyuan.jpg</path>
     </person>

     <person id="7">
         <name>成吉思汗</name>
         <sex>男</sex>
         <age>40</age>
         <path>http://192.168.5.10:8080/FileServer/sunbiin.jpg</path>
     </person>

     <person id="8">
         <name>李渊</name>
         <sex>男</sex>
         <age>36</age>
         <path>http://192.168.5.10:8080/FileServer/sunwu.jpg</path>
     </person>

     <person id="9">
         <name>李隆基</name>
         <sex>男</sex>
         <age>32</age>
         <path>http://192.168.5.10:8080/FileServer/wangwu.jpg</path>
     </person>
     <person id="10">
         <name>武则天</name>
         <sex>女</sex>
         <age>55</age>
         <path>http://192.168.5.10:8080/FileServer/wuzetian.jpg</path>
     </person>
 </Persons>

运行结果如下