ANDROID_MARS学习笔记_S01原始版_020_Mp3player001_歌曲列表

一、项目设计

二、歌曲列表简介

1.利用java.net.HttpURLConnection以流的形式下载xml文件为String

2.自定义ContentHandler--》Mp3ListContentHandler

3.利用自定义的ContentHandler和javax.xml.parsers.SAXParserFactory生成org.xml.sax.XMLReader，用来处理下载的xml字符串，处理结果以List<Mp3Info>返回

4.以返回的List<Mp3Info>和布局文件创建android.widget.SimpleAdapter

5.最后在activity中调用setListAdapter(adapter)，完成更新列表操作

二、代码
1.xml
(1)main.xml

 <?xml version="1.0" encoding="utf-8"?>
 <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
     android:orientation="vertical" android:layout_width="fill_parent"
     android:layout_height="fill_parent">
     <LinearLayout android:id="@+id/listLinearLayout"
         android:layout_width="fill_parent" android:layout_height="wrap_content"
         android:orientation="vertical">
         <ListView android:id="@id/android:list" android:layout_width="fill_parent"
             android:layout_height="wrap_content" android:drawSelectorOnTop="false"
             android:scrollbars="vertical" />
     </LinearLayout>
 </LinearLayout>

(2)AndroidManifest.xml

 <?xml version="1.0" encoding="utf-8"?>
 <manifest xmlns:android="http://schemas.android.com/apk/res/android"
     package="tony.mp3player"
     android:versionCode="1"
     android:versionName="1.0" >

     <uses-sdk
         android:minSdkVersion="8"
         android:targetSdkVersion="21" />

     <application
         android:allowBackup="true"
         android:icon="@drawable/ic_launcher"
         android:label="@string/app_name"
         android:theme="@style/AppTheme" >
         <activity
             android:name=".Mp3ListActivity"
             android:label="@string/app_name" >
             <intent-filter>
                 <action android:name="android.intent.action.MAIN" />

                 <category android:name="android.intent.category.LAUNCHER" />
             </intent-filter>
         </activity>
     </application>
     <uses-permission android:name="android.permission.INTERNET"/>
 </manifest>

3.mp3info_item.xml

 <?xml version="1.0" encoding="utf-8"?>
 <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
     android:layout_width="fill_parent"
     android:layout_height="fill_parent"
     android:orientation="horizontal"
     android:paddingLeft="10dip"
     android:paddingRight="10dip"
     android:paddingTop="1dip"
     android:paddingBottom="1dip"
     >
     <TextView android:id="@+id/mp3Name"
     android:layout_height="30dip"
     android:layout_width="180dip"
     android:textSize="10pt"/>
     <TextView android:id="@+id/mp3Size"
     android:layout_height="30dip"
     android:layout_width="180dip"
     android:textSize="10pt"/>
 </LinearLayout>

2.java
(1)Mp3ListActivity.java

 package tony.mp3player;

 import java.io.IOException;
 import java.io.StringReader;
 import java.util.ArrayList;
 import java.util.HashMap;
 import java.util.Iterator;
 import java.util.List;
 import java.util.Map;

 import javax.xml.parsers.ParserConfigurationException;
 import javax.xml.parsers.SAXParserFactory;

 import org.xml.sax.InputSource;
 import org.xml.sax.SAXException;
 import org.xml.sax.XMLReader;

 import tony.download.HttpDownloader;
 import tony.model.Mp3Info;
 import tony.xml.Mp3ListContentHandler;
 import android.annotation.SuppressLint;
 import android.app.ListActivity;
 import android.os.Bundle;
 import android.os.StrictMode;
 import android.view.Menu;
 import android.view.MenuItem;
 import android.widget.SimpleAdapter;

 @SuppressLint("NewApi")
 public class Mp3ListActivity extends ListActivity {
     private static final int UPDATE = 1;
     private static final int ABOUT = 1;
     @Override
     protected void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
         setContentView(R.layout.main);
         if (android.os.Build.VERSION.SDK_INT > 9) {
             StrictMode.ThreadPolicy policy = new StrictMode.ThreadPolicy.Builder().permitAll().build();
             StrictMode.setThreadPolicy(policy);
         }
         updateListView();
     }

     /**
      * 在用点击MENU按钮之后，会调用该方法，我们可以在这个方法当中加入自己的按钮控件
      */
     @Override
     public boolean onCreateOptionsMenu(Menu menu) {
         menu.add(0, UPDATE, UPDATE, R.string.mp3list_update);
         menu.add(0, ABOUT, ABOUT, R.string.mp3list_about);
         return super.onCreateOptionsMenu(menu);
     }

     /**
      * 当菜单选项被选中时调用
      */
     @Override
     public boolean onOptionsItemSelected(MenuItem item) {
         System.out.println("onOptionsItemSelected--->ItemId="+item.getItemId());
         switch (item.getItemId()) {
         case UPDATE:
             updateListView();
             break;
         case 2:
             break;
         default:
             break;
         }
         return super.onOptionsItemSelected(item);
     }

     private void updateListView() {
         String xml = downloadXML("http://192.168.1.104:8080/mp3/resources.xml");
         List<Mp3Info> infos = parse(xml);
         SimpleAdapter adapter = buidSimpleAdapter(infos);
         setListAdapter(adapter);
     }

     private SimpleAdapter buidSimpleAdapter(List<Mp3Info> infos) {
         // 生成一个List对象，并按照SimpleAdapter的标准，将mp3Infos当中的数据添加到List当中去
         List<HashMap<String, String>> list = new ArrayList<HashMap<String, String>>();
         HashMap<String,String> map = null;
         Mp3Info info = null;
         for(Iterator it = infos.iterator() ; it.hasNext() ;) {
             info = (Mp3Info) it.next();
             map = new HashMap<String,String>();
             map.put("mp3Name", info.getMp3Name());
             map.put("mp3Size", info.getMp3Size());
             list.add(map);
         }
         SimpleAdapter adapter = new SimpleAdapter(this, list, R.layout.mp3info_item,
                 new String[]{"mp3Name", "mp3Size"}, new int[]{R.id.mp3Name, R.id.mp3Size});
         return adapter;
     }

     private String downloadXML(String urlStr) {
         HttpDownloader httpDownloader = new HttpDownloader();
         String result = httpDownloader.download(urlStr);
         return result;
     }

     private List<Mp3Info> parse(String xml) {
         SAXParserFactory spf =  SAXParserFactory.newInstance();
         List<Mp3Info> infos = new ArrayList<Mp3Info>();
         try {
             XMLReader reader = spf.newSAXParser().getXMLReader();
             Mp3ListContentHandler handler = new Mp3ListContentHandler(infos);
             reader.setContentHandler(handler);
             reader.parse(new InputSource(new StringReader(xml)));
             for(Iterator it = infos.iterator();it.hasNext();) {
                 Mp3Info info = (Mp3Info) it.next();
                 System.out.println(info);
             }
         } catch (SAXException e) {
             e.printStackTrace();
         } catch (ParserConfigurationException e) {
             e.printStackTrace();
         } catch (IOException e) {
             e.printStackTrace();
         }
         return infos;
     }
 }

(2)Mp3ListContentHandler.java

 package tony.xml;

 import java.util.List;

 import org.xml.sax.Attributes;
 import org.xml.sax.SAXException;
 import org.xml.sax.helpers.DefaultHandler;

 import tony.model.Mp3Info;

 public class Mp3ListContentHandler extends DefaultHandler {

     private List<Mp3Info> infos = null;
     private Mp3Info mp3Info = null;
     private String tagName = null;

     public Mp3ListContentHandler(List<Mp3Info> infos) {
         super();
         this.infos = infos;
     }

     @Override
     public void startDocument() throws SAXException {
         super.startDocument();
     }

     @Override
     public void endDocument() throws SAXException {
         super.endDocument();
     }

     @Override
     public void startElement(String uri, String localName, String qName,
             Attributes attributes) throws SAXException {
         this.tagName = localName;
         if(tagName.equals("resource")) {
             mp3Info = new Mp3Info();
         }
     }

     @Override
     public void endElement(String uri, String localName, String qName)
             throws SAXException {
         if(qName.equals("resource")) {
             infos.add(mp3Info);
         }
         tagName = "";
     }

     @Override
     public void characters(char[] ch, int start, int length)
             throws SAXException {
         String temp = new String(ch, start, length);
         if(tagName.equals("id"))
             mp3Info.setId(temp);
         else if(tagName.equals("mp3.name"))
             mp3Info.setMp3Name(temp);
         else if(tagName.equals("mp3.size"))
             mp3Info.setMp3Size(temp);
         else if(tagName.equals("lrc.name"))
             mp3Info.setLrcName(temp);
         else if(tagName.equals("lrc.size"))
             mp3Info.setLrcSize(temp);
     }
 }

(3)HttpDownloader.java

 package tony.download;

 import java.io.BufferedReader;
 import java.io.InputStreamReader;
 import java.net.HttpURLConnection;
 import java.net.URL;

 public class HttpDownloader {

     /**
      * 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
      * 1.创建一个URL对象
      * 2.通过URL对象，创建一个HttpURLConnection对象
      * 3.得到InputStram
      * 4.从InputStream当中读取数据
      * @param urlStr
      * @return
      */
     public String download(String urlStr) {
         StringBuffer sb = new StringBuffer();
         String line = null;
         BufferedReader buffer = null;
         try {
             // 创建一个URL对象
             URL url = new URL(urlStr);
             // 创建一个Http连接
             HttpURLConnection urlConn = (HttpURLConnection) url
                     .openConnection();
             // 使用IO流读取数据
             buffer = new BufferedReader(new InputStreamReader(urlConn
                     .getInputStream()));
             while ((line = buffer.readLine()) != null) {
                 sb.append(line);
             }
         } catch (Exception e) {
             e.printStackTrace();
         } finally {
             try {
                 buffer.close();
             } catch (Exception e) {
                 e.printStackTrace();
             }
         }
         return sb.toString();
     }
 }

(4)

 package tony.model;

 public class Mp3Info {

     private String id,mp3Name,mp3Size,lrcName,lrcSize;

     public Mp3Info() {
         super();
     }

     public Mp3Info(String id, String mp3Name, String mp3Size, String lrcName,
             String lrcSize) {
         super();
         this.id = id;
         this.mp3Name = mp3Name;
         this.mp3Size = mp3Size;
         this.lrcName = lrcName;
         this.lrcSize = lrcSize;
     }

     @Override
     public String toString() {
         return "Mp3Info [id=" + id + ", mp3Name=" + mp3Name + ", mp3Size="
                 + mp3Size + ", lrcName=" + lrcName + ", lrcSize=" + lrcSize
                 + "]";
     }

     public String getId() {
         return id;
     }

     public void setId(String id) {
         this.id = id;
     }

     public String getMp3Name() {
         return mp3Name;
     }

     public void setMp3Name(String mp3Name) {
         this.mp3Name = mp3Name;
     }

     public String getMp3Size() {
         return mp3Size;
     }

     public void setMp3Size(String mp3Size) {
         this.mp3Size = mp3Size;
     }

     public String getLrcName() {
         return lrcName;
     }

     public void setLrcName(String lrcName) {
         this.lrcName = lrcName;
     }

     public String getLrcSize() {
         return lrcSize;
     }

     public void setLrcSize(String lrcSize) {
         this.lrcSize = lrcSize;
     }

 }

四、运行结果