mp3播放器(一)（从服务器端下载xml文件）

Mp3ListActivity.java

  1 package com.example.mp3player00;
  2 
  3 import java.io.IOException;
  4 import java.io.StringReader;
  5 import java.util.ArrayList;
  6 import java.util.Iterator;
  7 import java.util.List;
  8 
  9 import javax.xml.parsers.ParserConfigurationException;
 10 import javax.xml.parsers.SAXParserFactory;
 11 
 12 import org.xml.sax.InputSource;
 13 import org.xml.sax.SAXException;
 14 import org.xml.sax.XMLReader;
 15 
 16 import xml.Mp3ListContentHandler;
 17 
 18 import model.Mp3Info;
 19 
 20 import com.example.download.HttpDownloader;
 21 
 22 import android.os.Bundle;
 23 import android.app.Activity;
 24 import android.app.ListActivity;
 25 import android.view.Menu;
 26 import android.view.MenuItem;
 27 
 28 public class Mp3ListActivity extends ListActivity {
 29     private static final int upadate=1;
 30     private static final int about=2;
 31    //以上定义常量，看到值的名字就知道按钮的名字    
 32    //且为后面修改提供方便
 33     @Override
 34     protected void onCreate(Bundle savedInstanceState) {
 35         super.onCreate(savedInstanceState);
 36         setContentView(R.layout.activity_mp3_list);
 37     }
 38 
 39     @Override
 40     public boolean onCreateOptionsMenu(Menu menu) {
 41         // Inflate the menu; this adds items to the action bar if it is present.
 42         getMenuInflater().inflate(R.menu.activity_mp3_list, menu);
 43         menu.add(0, 1, 1,R.string.mp3list_update);
 44         menu.add(0, 2, 2, R.string.mp3list_about);
 45         return true;
 46     }
 47 
 48     @Override
 49     public boolean onOptionsItemSelected(MenuItem item) {
 50         // TODO Auto-generated method stub
 51         //System.out.println("--->"+item.getItemId());
 52         if(item.getItemId()==upadate)
 53         {
 54             //用户点击了更新按钮
 55     
 56             String xml=downloadXML("http://192.168.1.100:8080/mp3/resources.xml");
 57             //System.out.println("----->"+xml);
 58             try {
 59                 parse(xml);
 60             } catch (IOException e) {
 61                 // TODO Auto-generated catch block
 62                 e.printStackTrace();
 63             }
 64         }
 65         else if(item.getItemId()==about)
 66         {
 67             //用户点击了关于按钮
 68         }
 69         return super.onOptionsItemSelected(item);
 70     }
 71     //写一个单独的下载函数，更加清晰
 72     private String downloadXML(String urlStr) 
 73     {
 74         
 75         HttpDownloader httpdownloader=new HttpDownloader(); 
 76         String result=httpdownloader.download(urlStr);
 77         return result;
 78     }
 79     //在这个函数中解析xml
 80     //首先生成xml解析器
 81     private List<Mp3Info> parse(String xmlStr) throws IOException
 82     {
 83         SAXParserFactory saxParserFactory=SAXParserFactory.newInstance();
 84         try {
 85             XMLReader xmlReader=saxParserFactory.newSAXParser().getXMLReader();
 86             List<Mp3Info> info=new ArrayList<Mp3Info>();
 87             Mp3ListContentHandler  mp3ListContentHandler=new Mp3ListContentHandler(info);
 88             xmlReader.setContentHandler(mp3ListContentHandler);
 89             xmlReader.parse(new InputSource(new StringReader(xmlStr)));
 90             //解析完数据都天道info里面，然后用for循环迭代出来
 91             for (Iterator iterator = info.iterator(); iterator.hasNext();) {
 92                 Mp3Info mp3Info = (Mp3Info) iterator.next();
 93                 System.out.println(mp3Info);
 94             }
 95             
 96         } catch (SAXException e) {
 97             // TODO Auto-generated catch block
 98             e.printStackTrace();
 99         } catch (ParserConfigurationException e) {
100             // TODO Auto-generated catch block
101             e.printStackTrace();
102         }
103         
104         return null;
105     }
106 
107 }

HttpDownloader.java

 1 package com.example.download;
 2 
 3 import java.io.BufferedReader;
 4 import java.io.IOException;
 5 import java.io.InputStreamReader;
 6 import java.net.HttpURLConnection;
 7 import java.net.MalformedURLException;
 8 import java.net.URL;
 9 
10 public class HttpDownloader {
11 
12     /**
13      * 根据URL下载文件，前提是这个文件当中的内容是文本，函数的返回值就是文件当中的内容
14      * 1.创建一个URL对象
15      * 2.通过URL对象，创建一个HttpURLConnection对象
16      * 3.得到InputStram
17      * 4.从InputStream当中读取数据
18      * @param urlStr
19      * @return
20      */
21     public String download(String urlStr) {
22         StringBuffer sb = new StringBuffer();
23         String line = null;
24         BufferedReader buffer = null;
25         try {
26             // 创建一个URL对象
27             URL url = new URL(urlStr);
28             // 创建一个Http连接
29             HttpURLConnection urlConn = (HttpURLConnection) url
30                     .openConnection();
31             // 使用IO流读取数据
32             buffer = new BufferedReader(new InputStreamReader(urlConn
33                     .getInputStream()));
34             while ((line = buffer.readLine()) != null) {
35                 sb.append(line);
36             }
37         } catch (Exception e) {
38             e.printStackTrace();
39         } finally {
40             try {
41                 buffer.close();
42             } catch (Exception e) {
43                 e.printStackTrace();
44             }
45         }
46         return sb.toString();
47     }
48 }

Mp3Info.java

 1 package model;
 2 /**
 3  * 把每一个<rescource>看成一个对象 mp3info对象 建一个实体类，代表现实中一个实体
 4  * Mp3info实体类
 5  * @author kyx
 6  */
 7 public class Mp3Info {
 8    private String id;
 9    private String mp3Name;
10    private String mp3Size;
11    private String IrcName;
12    private String IrcSize;
13 public String getId() {
14     return id;
15 }
16 public void setId(String id) {
17     this.id = id;
18 }
19 public String getMp3Name() {
20     return mp3Name;
21 }
22 public void setMp3Name(String mp3Name) {
23     this.mp3Name = mp3Name;
24 }
25 public String getMp3Size() {
26     return mp3Size;
27 }
28 public void setMp3Size(String mp3Size) {
29     this.mp3Size = mp3Size;
30 }
31 public String getIrcName() {
32     return IrcName;
33 }
34 public void setIrcName(String ircName) {
35     IrcName = ircName;
36 }
37 public String getIrcSize() {
38     return IrcSize;
39 }
40 public void setIrcSize(String ircSize) {
41     IrcSize = ircSize;
42 }
43 //还要生成一些构造函数，构造函数起码要有两个，一个是带参数的，一个是不带参数的
44 public Mp3Info(String id, String mp3Name, String mp3Size, String ircName,
45         String ircSize) {
46     super();
47     this.id = id;
48     this.mp3Name = mp3Name;
49     this.mp3Size = mp3Size;
50     IrcName = ircName;
51     IrcSize = ircSize;
52 }
53 //不带参数的的构造函数
54 public Mp3Info() {
55     super();
56 }
57 @Override
58 public String toString() {
59     return "Mp3Info [id=" + id + ", mp3Name=" + mp3Name + ", mp3Size="
60             + mp3Size + ", IrcName=" + IrcName + ", IrcSize=" + IrcSize + "]";
61 }
62 //toString方便测试鉴定
63 }

Mp3ContentHandler.java

  1 package xml;
  2 
  3 import java.util.List;
  4 
  5 import model.Mp3Info;
  6 
  7 import org.xml.sax.Attributes;
  8 import org.xml.sax.SAXException;
  9 import org.xml.sax.helpers.DefaultHandler;
 10 //解析
 11 //内容处理器 ContentHandler 接口是解析xm的主体
 12 //handler使用的是adapter的设计模式
 13 //Adapter是连接后端数据和前端显示的适配器接口，
 14 //是数据和UI（View）之间一个重要的纽带。在常见的View(ListView,GridView)等地方都需要用到Adapter
 15 public class Mp3ListContentHandler extends DefaultHandler {
 16     private List<Mp3Info> info=null;//这边每次解析resource标签都会放入一个Mp3Info对象当中 ，一个标签就是一resource,再把每个对象放入List
 17     //Mp3ListActivity在调用此类的时候会生成List并且传进来
 18     private Mp3Info mp3info=null;//mp3info里面就是存放resource的值
 19     private String tagname;
 20     
 21     //添加get和set方便访问
 22     public List<Mp3Info> getInfo() {
 23         return info;
 24     }
 25 
 26     public void setInfo(List<Mp3Info> info) {
 27         this.info = info;
 28     }
 29     
 30     //Mp3ListActivity在调用此类的时候会生成List并且传进来
 31     public Mp3ListContentHandler(List<Mp3Info> info) {
 32         super();
 33         this.info = info;
 34     }
 35 
 36     @Override
 37    //遇到id这个标签，将值赋给Mp3Info的id属性
 38     public void characters(char[] ch, int start, int length)
 39             throws SAXException {
 40         // TODO Auto-generated method stub
 41         super.characters(ch, start, length);
 42         String temp=new String(ch,start,length);
 43         if(tagname.equals("id"))
 44         {
 45             mp3info.setId(temp);//如果标签是“id”，就把值赋予mp3info对象中的id变量中
 46         }
 47         else if(tagname.equals("mp3.name"))
 48         {
 49             mp3info.setMp3Name(temp);
 50         }
 51         else if(tagname.equals("mp3.size"))
 52         {
 53             mp3info.setMp3Size(temp);
 54         }
 55         else if(tagname.equals("Irc.name"))
 56         {
 57             mp3info.setIrcName(temp);
 58         }
 59         else if(tagname.equals("Irc.size"))
 60         {
 61             mp3info.setIrcSize(temp);
 62         }
 63         
 64     }
 65 
 66     @Override
 67     public void endDocument() throws SAXException {
 68         // TODO Auto-generated method stub
 69         super.endDocument();
 70     }
 71 
 72     @Override
 73     //标签解析结束
 74     public void endElement(String uri, String localName, String qName)
 75             throws SAXException {
 76         // TODO Auto-generated method stub
 77         super.endElement(uri, localName, qName);
 78         if(qName.equals("resource"))//这里用qName而不是tagname
 79         {
 80             info.add(mp3info);//如果遇到resource结尾，那么就把这个对象放入到List中
 81         }
 82         tagname="";
 83     }
 84 
 85     @Override
 86     public void startDocument() throws SAXException {
 87         // TODO Auto-generated method stub
 88         super.startDocument();
 89     }
 90 
 91     @Override
 92     //开始解析标签
 93     public void startElement(String uri, String localName, String qName,
 94             Attributes attributes) throws SAXException {
 95         // TODO Auto-generated method stub
 96         super.startElement(uri, localName, qName, attributes);
 97         this.tagname=localName;
 98         if(tagname.equals("resource"))
 99         {
100             mp3info=new Mp3Info();
101         }
102     }
103 
104 }

layout xml文件配合listView

 1 <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
 2     android:orientation="vertical" android:layout_width="fill_parent"
 3     android:layout_height="fill_parent">
 4     <LinearLayout android:id="@+id/listLinearLayout"
 5         android:layout_width="fill_parent" android:layout_height="wrap_content"
 6         android:orientation="vertical">
 7         <ListView android:id="@id/android:list" android:layout_width="fill_parent"
 8             android:layout_height="wrap_content" android:drawSelectorOnTop="true"
 9             android:scrollbars="vertical" />
10     </LinearLayout>
11 </LinearLayout>

在Manifest中添加

<uses-permission android:name="android.permission.INTERNET" />