Android中ListView异步加载数据
http://www.cnblogs.com/snake-hand/p/3206655.html
1.主Activity
1 public class MainActivity extends Activity { 2 3 private ListView listView; 4 private ArrayList<Person> persons; 5 private ListAdapter adapter; 6 private Handler handler=null; 7 //xml文件的网络地址 8 final String path="http://192.168.5.10:8080/FileServer/person.xml"; 9 @SuppressLint("HandlerLeak") 10 protected void onCreate(Bundle savedInstanceState) { 11 super.onCreate(savedInstanceState); 12 setContentView(R.layout.main); 13 14 listView=(ListView) super.findViewById(R.id.listview); 15 //cache=new File(Environment.getExternalStorageDirectory().getAbsolutePath()+"/cache"); 16 17 //开一条子线程加载网络数据 18 Runnable runnable=new Runnable() 19 { 20 public void run() 21 { 22 try 23 { 24 Thread.sleep(2000); 25 //xmlwebData解析网络中xml中的数据 26 persons=XmlwebData.getData(path); 27 //发送消息，并把persons结合对象传递过去 28 handler.sendMessage(handler.obtainMessage(0, persons)); 29 } 30 catch (InterruptedException e) 31 { 32 e.printStackTrace(); 33 } 34 } 35 }; 36 37 try 38 { 39 //开启线程 40 new Thread(runnable).start(); 41 //handler与线程之间的通信及数据处理 42 handler=new Handler() 43 { 44 public void handleMessage(Message msg) 45 { 46 if(msg.what==0) 47 { 48 //msg.obj是获取handler发送信息传来的数据 49 @SuppressWarnings("unchecked") 50 ArrayList<Person> person=(ArrayList<Person>) msg.obj; 51 //给ListView绑定数据 52 BinderListData(person); 53 } 54 } 55 }; 56 } 57 catch (Exception e) 58 { 59 e.printStackTrace(); 60 } 61 } 62 63 //绑定数据 64 public void BinderListData(ArrayList<Person> person) 65 { 66 //创建adapter对象 67 adapter=new ListViewAdapter(R.layout.item,this,person); 68 //将Adapter绑定到listview中 69 listView.setAdapter(adapter); 70 } 71 72 }
2.从网络中获取xml文件并解析数据
1 public class XmlwebData 2 { 4 private static ArrayList<Person> persons=null;
5
6 public static ArrayList<Person> getData(final String path) 7 { 8 try 9 { 10 URL url=new URL(path); 11 Person person=null; 12 13 HttpURLConnection conn=(HttpURLConnection) url.openConnection(); 14 conn.setRequestMethod("GET"); 15 conn.setConnectTimeout(5000); 16 if(conn.getResponseCode()==200) 17 { 18 InputStream inputstream=conn.getInputStream(); 21 XmlPullParser xml=Xml.newPullParser(); 22 xml.setInput(inputstream, "UTF-8"); 23 int event=xml.getEventType(); 24 25 while(event!=XmlPullParser.END_DOCUMENT) 26 { 27 switch (event) 28 { 29 //开始解析文档 30 case XmlPullParser.START_DOCUMENT: 31 persons=new ArrayList<Person>(); 32 break; 33 case XmlPullParser.START_TAG: 34 35 String value=xml.getName(); 36 if(value.equals("person")) 37 {//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 38 person=new Person(); 39 //获取属性值 40 person.setId(new Integer(xml.getAttributeValue(0))); 41 } 42 else if(value.equals("name")) 43 { 44 person.setName(xml.nextText()); 45 } 46 else if(value.equals("sex")) 47 { 48 person.setSex(xml.nextText()); 49 } 50 else if(value.equals("age")) 51 { 52 person.setAge(new Integer(xml.nextText())); 53 } 54 else if(value.equals("path")) 55 { 56 person.setPath(xml.nextText()); 57 } 58 break; 59 case XmlPullParser.END_TAG: 60 if(xml.getName().equals("person")) 61 { 62 persons.add(person); 63 System.out.println(person.getName());; 64 person=null; 65 } 66 break; 67 } 68 //解析下一个对象 69 event=xml.next(); 70 } 71 return persons; 72 } 73 } 74 catch (Exception e) 75 { 76 e.printStackTrace(); 77 } 78 79 80 return null; 81 82 } 83 84 }
3.Person对象类
1 public class Person 2 { 3 private int id; 4 private String name; 5 private String sex; 6 private String path; 7 public String getPath() { 8 return path; 9 } 10 public void setPath(String path) { 11 this.path = path; 12 } 13 private int age; 14 public int getId() { 15 return id; 16 } 17 public void setId(int id) { 18 this.id = id; 19 } 20 public String getName() { 21 return name; 22 } 23 public void setName(String name) { 24 this.name = name; 25 } 26 public String getSex() { 27 return sex; 28 } 29 public void setSex(String sex) { 30 this.sex = sex; 31 } 32 public int getAge() { 33 return age; 34 } 35 public void setAge(int age) { 36 this.age = age; 37 } 38 public Person(){ 39 40 } 41 }
4.Adapter数据适配器类
1 public class ListViewAdapter extends BaseAdapter implements ListAdapter 2 { 3 4 private ArrayList<Person> data; 5 private int id; 6 private Context context; 7 private LayoutInflater inflater; 8 public ListViewAdapter(int item, MainActivity mainActivity,ArrayList<Person> data) 9 { 10 this.data=data; 11 this.context=mainActivity; 12 this.id=item; 13 inflater=LayoutInflater.from(context); 14 } 15 16 @Override 17 public int getCount() 18 { 19 return data.size(); 20 } 21 22 @Override 23 public Object getItem(int position) 24 { 25 return data.get(position); 26 } 27 28 @Override 29 public long getItemId(int position) 30 { 31 return position; 32 } 33 34 @Override 35 public View getView(int position, View view, ViewGroup arg2) 36 { 37 TextView name=null; 38 TextView sex=null; 39 TextView age=null; 40 ImageView img=null; 41 if(view==null) 42 { 43 view=inflater.inflate(id, null); 44 name=(TextView) view.findViewById(R.id.PersonName); 45 sex=(TextView) view.findViewById(R.id.PersonSex); 46 age=(TextView) view.findViewById(R.id.PersonAge); 47 img=(ImageView) view.findViewById(R.id.Personimage); 48 //保存view对象到ObjectClass类中 49 view.setTag(new ObjectClass(name,sex,age,img)); 50 } 51 else 52 { 53 //得到保存的对象 54 ObjectClass objectclass=(ObjectClass) view.getTag(); 55 name=objectclass.name; 56 sex=objectclass.sex; 57 age=objectclass.age; 58 img=objectclass.img; 59 } 60 61 Person person=(Person) data.get(position); 62 //帮数据绑定到控件上 63 name.setText(person.getName().toString()); 64 sex.setText("性别："+person.getSex().toString()); 65 age.setText("年龄："+String.valueOf(person.getAge())); 66 //加载图片资源 67 LoadImage(img,person.getPath()); 68 return view; 69 70 } 71 72 private void LoadImage(ImageView img, String path) 73 { 74 //异步加载图片资源 75 AsyncTaskImageLoad async=new AsyncTaskImageLoad(img); 76 //执行异步加载，并把图片的路径传送过去 77 async.execute(path); 78 79 } 80 81 private final class ObjectClass 82 { 83 TextView name=null; 84 TextView sex=null; 85 TextView age=null; 86 ImageView img=null; 87 public ObjectClass(TextView name, TextView sex, TextView age,ImageView img) 88 { 89 this.name=name; 90 this.sex=sex; 91 this.age=age; 92 this.img=img; 93 } 94 } 95 97 }
5.异步加载图片类
1 public class AsyncTaskImageLoad extends AsyncTask<String, Integer, Bitmap> { 2 3 private ImageView Image=null; 4 5 public AsyncTaskImageLoad(ImageView img) 6 { 7 Image=img; 8 } 9 //运行在子线程中 10 protected Bitmap doInBackground(String... params) { 11 try 12 { 13 URL url=new URL(params[0]); 14 HttpURLConnection conn=(HttpURLConnection) url.openConnection(); 15 conn.setRequestMethod("POST"); 16 conn.setConnectTimeout(5000); 17 if(conn.getResponseCode()==200) 18 { 19 InputStream input=conn.getInputStream(); 20 Bitmap map=BitmapFactory.decodeStream(input); 21 return map; 22 } 23 } catch (Exception e) 24 { 25 e.printStackTrace(); 26 } 27 return null; 28 } 29 30 protected void onPostExecute(Bitmap result) 31 { 32 if(Image!=null && result!=null) 33 { 34 Image.setImageBitmap(result); 35 } 36 37 super.onPostExecute(result); 38 } 39 }
6.网络中的person.xml文件内容为
1 <?xml version="1.0" encoding="UTF-8"?> 2 <Persons> 3 <person id="1"> 4 <name>张三</name> 5 <sex>男</sex> 6 <age>25</age> 7 <path>http://192.168.5.10:8080/FileServer/chengjisihan.jpg</path> 8 </person> 9 <person id="2"> 10 <name>李斯</name> 11 <sex>男</sex> 12 <age>78</age> 13 <path>http://192.168.5.10:8080/FileServer/laozi.jpg</path> 14 </person> 15 <person id="3"> 16 <name>王五</name> 17 <sex>男</sex> 18 <age>22</age> 19 <path>http://192.168.5.10:8080/FileServer/lilongji.jpg</path> 20 </person> 21 <person id="4"> 22 <name>庞聪</name> 23 <sex>男</sex> 24 <age>31</age> 25 <path>http://192.168.5.10:8080/FileServer/lishimin.jpg</path> 26 </person> 27 <person id="5"> 28 <name>孙膑</name> 29 <sex>男</sex> 30 <age>48</age> 31 <path>http://192.168.5.10:8080/FileServer/lisi.jpg</path> 32 </person> 33 <person id="6"> 34 <name>孙武</name> 35 <sex>男</sex> 36 <age>58</age> 37 <path>http://192.168.5.10:8080/FileServer/liyuan.jpg</path> 38 </person> 39 40 <person id="7"> 41 <name>成吉思汗</name> 42 <sex>男</sex> 43 <age>40</age> 44 <path>http://192.168.5.10:8080/FileServer/sunbiin.jpg</path> 45 </person> 46 47 <person id="8"> 48 <name>李渊</name> 49 <sex>男</sex> 50 <age>36</age> 51 <path>http://192.168.5.10:8080/FileServer/sunwu.jpg</path> 52 </person> 53 54 <person id="9"> 55 <name>李隆基</name> 56 <sex>男</sex> 57 <age>32</age> 58 <path>http://192.168.5.10:8080/FileServer/wangwu.jpg</path> 59 </person> 60 <person id="10"> 61 <name>武则天</name> 62 <sex>女</sex> 63 <age>55</age> 64 <path>http://192.168.5.10:8080/FileServer/wuzetian.jpg</path> 65 </person> 66 </Persons>
