mp3播放器（四）（从服务器端下载mp3文件+service的应用+SDcard操作）

下载到本地的sd卡中实现序列化接口 serializable 加一个id 表示接口通过一个什么样的方式可以把对象变成字节码从内存中发送出去。。。。。实体类中toString。。。能够把里面的参数都答应出来，直接写类名就行，特别方便下载要放在线程里面执行，就创建一个内部类

下载文件的过程 1,得到用户所要下载的Mp3文件的名称，靠position获取名字 2,访问网络下载mp3文件 3，通知客户下载的结果

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.HashMap;
  7 import java.util.Iterator;
  8 import java.util.List;
  9 
 10 import javax.xml.parsers.ParserConfigurationException;
 11 import javax.xml.parsers.SAXParserFactory;
 12 
 13 import org.xml.sax.InputSource;
 14 import org.xml.sax.SAXException;
 15 import org.xml.sax.XMLReader;
 16 
 17 import service.DownloadService;
 18 
 19 import xml.Mp3ListContentHandler;
 20 
 21 import model.Mp3Info;
 22 
 23 import com.example.download.HttpDownloader;
 24 
 25 import android.os.Bundle;
 26 import android.app.Activity;
 27 import android.app.ListActivity;
 28 import android.content.Intent;
 29 import android.view.Menu;
 30 import android.view.MenuItem;
 31 import android.view.View;
 32 import android.widget.ListView;
 33 import android.widget.SimpleAdapter;
 34 
 35 public class Mp3ListActivity extends ListActivity {
 36     private static final int upadate=1;
 37     private static final int about=2;
 38     private List<Mp3Info> mp3Infos=null;
 39    //以上定义常量，看到值的名字就知道按钮的名字    
 40    //且为后面修改提供方便
 41     @Override
 42     protected void onCreate(Bundle savedInstanceState) {
 43         super.onCreate(savedInstanceState);
 44         setContentView(R.layout.activity_mp3_list);
 45         updateListView();
 46     }
 47 
 48     @Override
 49     public boolean onCreateOptionsMenu(Menu menu) {
 50         // Inflate the menu; this adds items to the action bar if it is present.
 51         getMenuInflater().inflate(R.menu.activity_mp3_list, menu);
 52         menu.add(0, 1, 1,R.string.mp3list_update);
 53         menu.add(0, 2, 2, R.string.mp3list_about);
 54         return true;
 55     }
 56 
 57     @Override
 58     public boolean onOptionsItemSelected(MenuItem item) {
 59         // TODO Auto-generated method stub
 60         //System.out.println("--->"+item.getItemId());
 61         if(item.getItemId()==upadate)
 62         {
 63             updateListView();
 64             
 65             
 66         }
 67         else if(item.getItemId()==about)
 68         {
 69             //用户点击了关于按钮
 70         }
 71         return super.onOptionsItemSelected(item);
 72     }
 73     private SimpleAdapter buildSimpleAdapter(List<Mp3Info> mp3infos){
 74         //构建Adapter，首先生成一个List对象。List对象里面存的是HashMap，HashMap里面存的是String
 75         
 76         List<HashMap<String,String>> list=new ArrayList<HashMap<String,String>>();
 77         //将Mp3Info迭代出来
 78         for (Iterator iterator = mp3infos.iterator(); iterator.hasNext();) {
 79             Mp3Info mp3Info = (Mp3Info) iterator.next();
 80              //生成一个HashMap对象
 81             HashMap<String,String> map=new HashMap<String,String>();
 82             //构造一个map
 83             map.put("mp3_name", mp3Info.getMp3Name());
 84             map.put("mp3_size", mp3Info.getMp3Size());
 85             //构造好map后添加到List中，即将HashMap添加到List中
 86             list.add(map);
 87         }
 88         //生成adapter
 89         SimpleAdapter simpleAdapter=
     new SimpleAdapter(this,list,R.layout.mp3info_item,new String[]{"mp3_name","mp3_size"},new int[]{R.id.mp3_name,R.id.mp3_size});
 90         
 91         
 92         return simpleAdapter;
 93         
 94     }
 95     private void updateListView(){
 96         //用户点击了更新按钮
 97         
 98         String xml=downloadXML("http://192.168.1.100:8080/mp3/resources.xml");
 99         //System.out.println("----->"+xml);
100         
101         
102         
103             try {
104                 mp3Infos = parse(xml);
105             } catch (IOException e) {
106                 // TODO Auto-generated catch block
107                 e.printStackTrace();
108             }
109             //List<Mp3Info>可以看出一个int，String这样一个类型
110             SimpleAdapter simpleAdapter=buildSimpleAdapter(mp3Infos);
111             setListAdapter(simpleAdapter);
112             
113     }
114     //写一个单独的下载函数，更加清晰
115     private String downloadXML(String urlStr) 
116     {
117         
118         HttpDownloader httpdownloader=new HttpDownloader(); 
119         String result=httpdownloader.download(urlStr);
120         return result;
121     }
122     //在这个函数中解析xml
123     //首先生成xml解析器
124     private List<Mp3Info> parse(String xmlStr) throws IOException 
125     {
126         List<Mp3Info> info=new ArrayList<Mp3Info>();
127         SAXParserFactory saxParserFactory=SAXParserFactory.newInstance();
128         try {
129             XMLReader xmlReader=saxParserFactory.newSAXParser().getXMLReader();            
130             Mp3ListContentHandler  mp3ListContentHandler=new Mp3ListContentHandler(info);
131             xmlReader.setContentHandler(mp3ListContentHandler);
132             xmlReader.parse(new InputSource(new StringReader(xmlStr)));
133             //解析完数据都天道info里面，然后用for循环迭代出来
134             for (Iterator iterator = info.iterator(); iterator.hasNext();) {
135                 Mp3Info mp3Info = (Mp3Info) iterator.next();
136                 //System.out.println(mp3Info);
137             }
138             
139             
140         } catch (SAXException e) {
141             // TODO Auto-generated catch block
142             e.printStackTrace();
143         } catch (ParserConfigurationException e) {
144             // TODO Auto-generated catch block
145             e.printStackTrace();
146         }
147         return info;
148     
149     }
150     //第一个是选择的哪一个List，第二个是选择的哪一行，第三个是条目处于的位置，第四个是条目的id
151     
152     //点击第一个postion是0，就是代表第一行，就是List里面第0个元素，把List看成一个有顺序的链表，链表对象就是mp3infos
153     protected void onListItemClick(ListView l, View v, int position, long id) {
154         super.onListItemClick(l, v, position, id);
155         //根据用户点击的位置来确定获得哪一个mp3info对象
156         Mp3Info mp3info=mp3Infos.get(position);
157         //System.out.println("mp3info---"+mp3info);//因为已经复写了toString方法
158         //在这里启动service
159         Intent intent=new Intent();
160         //将mp3info放到intent里面去再传到service里面去
161         intent.putExtra("mp3info", mp3info);//将mp3info实现序列化
162         //设置跳转的目的地
163         intent.setClass(this, DownloadService.class);
164         //启动Service
165         startService(intent);
166         
167     }
168     
169 
170 }

DownloadService.java

 1 package service;
 2 
 3 import com.example.download.HttpDownloader;
 4 
 5 import model.Mp3Info;
 6 import android.app.Service;
 7 import android.content.Intent;
 8 import android.os.IBinder;
 9 
10 public class DownloadService extends Service {
11 
12     @Override
13     public IBinder onBind(Intent arg0) {
14         // TODO Auto-generated method stub
15         return null;
16     }
17     //Mp3ListActivity里面的,点击一行，onSelectedItem里的onStartService ,调用这里的onstart()
18     @Override
19     public void onStart(Intent intent, int startId) {
20         // TODO Auto-generated method stub
21         //从intent里面将mp3info取出来
22         Mp3Info mp3info=(Mp3Info) intent.getSerializableExtra("mp3info");
23         System.out.println("service----->"+mp3info);
24         DownloadThread downloadThread=new DownloadThread(mp3info);
25         Thread thread=new Thread(downloadThread);
26         thread.start();
27         super.onStart(intent, startId);
28     }
29     //onstar执行好，生成一个线程来执行下载
30     //创建线程的内部类
31     class DownloadThread implements Runnable{
32         //要能接受mp3info对象，创建构造函数
33         private Mp3Info mp3Info=null;
34         public DownloadThread(Mp3Info mp3Info){
35             this.mp3Info=mp3Info;
36             System.out.println("---in thread"+mp3Info.getMp3Name());
37         }
38         //在run里面实现下载
39             @Override
40       public void run() {
41         System.out.println("---in thread2"+mp3Info.getMp3Name());
42         // TODO Auto-generated method stub
43         //下载地址C:\apache-tomcat-7.0.42\webapps\mp3
44         String mp3Url="http://192.168.1.100:8080/mp3/"+mp3Info.getMp3Name();
45         HttpDownloader httpDownloader=new HttpDownloader();
46         int result=httpDownloader.downFile(mp3Url,"mp3/", mp3Info.getMp3Name());//放在sdcard里面哪个文件夹里
47     }
48     }
49 
50 
51 
52 }

HttpDownloader.java

 1 package com.example.download;
 2 
 3 import java.io.BufferedReader;
 4 import java.io.File;
 5 import java.io.IOException;
 6 import java.io.InputStream;
 7 import java.io.InputStreamReader;
 8 import java.net.HttpURLConnection;
 9 import java.net.MalformedURLException;
10 import java.net.URL;
11 import utils.FileUtils;
12 
13 
14 
15 public class HttpDownloader {
16 
17     /**
18      * 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
19      * 1.创建一个URL对象
20      * 2.通过URL对象，创建一个HttpURLConnection对象
21      * 3.得到InputStram
22      * 4.从InputStream当中读取数据
23      * @param urlStr
24      * @return
25      */
26     public String download(String urlStr) {
27         StringBuffer sb = new StringBuffer();
28         String line = null;
29         BufferedReader buffer = null;
30         try {
31             // 创建一个URL对象
32             URL url = new URL(urlStr);
33             // 创建一个Http连接
34             HttpURLConnection urlConn = (HttpURLConnection) url
35                     .openConnection();
36             // 使用IO流读取数据
37             buffer = new BufferedReader(new InputStreamReader(urlConn
38                     .getInputStream()));
39             while ((line = buffer.readLine()) != null) {
40                 sb.append(line);
41             }
42         } catch (Exception e) {
43             e.printStackTrace();
44         } finally {
45             try {
46                 buffer.close();
47             } catch (Exception e) {
48                 e.printStackTrace();
49             }
50         }
51         return sb.toString();
52     }
53     public int downFile(String urlStr, String path, String fileName) {
54         InputStream inputStream = null;
55         try {
56             FileUtils fileUtils = new FileUtils();
57             
58             if (fileUtils.isFileExist(  fileName,path)) {
59                 return 1;
60             } else {
61                 inputStream = getInputStreamFromUrl(urlStr);
62                 System.out.println("urlStr----->"+urlStr+"path-->"+path+"filename-->"+fileName);
63                 File resultFile = fileUtils.write2SDFromInput(path,fileName, inputStream);
64                 System.out.println("httpDownloader---->"+resultFile);
65                 if (resultFile == null) {
66                     return -1;
67                 }
68             }
69         } catch (Exception e) {
70             e.printStackTrace();
71             return -1;
72         } finally {
73             try {
74                 inputStream.close();
75             } catch (Exception e) {
76                 e.printStackTrace();
77             }
78         }
79         return 0;
80     }
81     public InputStream getInputStreamFromUrl(String urlStr)
82             throws MalformedURLException, IOException {
83         URL url = new URL(urlStr);
84         HttpURLConnection urlConn = (HttpURLConnection) url.openConnection();
85         InputStream inputStream = urlConn.getInputStream();
86         return inputStream;
87     }
88 }

FileUtils.java

 1 package utils;
 2 
 3 import java.io.File;
 4 import java.io.FileOutputStream;
 5 import java.io.IOException;
 6 import java.io.InputStream;
 7 import java.io.OutputStream;
 8 
 9 import android.os.Environment;
10 
11 public class FileUtils {
12     private String SDPATH;
13 
14     public String getSDPATH() {
15         return SDPATH;
16     }
17     public FileUtils() {
18         //得到当前外部存储设备的目录
19         // /SDCARD
20         SDPATH = Environment.getExternalStorageDirectory().getAbsolutePath()+File.separator;
21         System.out.println("判断SDCard是否存在，是否有可读权限："
22         + Environment.MEDIA_MOUNTED.endsWith(Environment.getExternalStorageState()));
23     }
24     /**
25      * 在SD卡上创建文件
26      * 
27      * @throws IOException
28      * 在哪个目录上生成这个文件，文件的名字
29      */
30     public File creatSDFile(String fileName,String dir) throws IOException {
31         File file = new File(SDPATH+dir + fileName);
32         System.out.println("file--->"+file);
33         file.createNewFile();
34         return file;
35     }
36     
37     /**
38      * 在SD卡上创建目录
39      * 
40      * @param dirName
41      */
42     public File creatSDDir(String dir) {
43         File dirFile = new File(SDPATH + dir+File.separator);
44         System.out.println("creatSDDir?---->"+dirFile.mkdirs());
45         return dirFile;
46     }
47 
48     /**
49      * 判断SD卡上的文件夹是否存在
50      */
51     public boolean isFileExist(String fileName,String path){
52         File file = new File(SDPATH + path+File.separator+fileName);
53         return file.exists();
54     }
55     
56     /**
57      * 将一个InputStream里面的数据写入到SD卡中
58      */
59     public File write2SDFromInput(String path,String fileName,InputStream input){
60         File file = null;
61         OutputStream output = null;
62         try{
63             creatSDDir(path);
64             file = creatSDFile( fileName,path );
65             output = new FileOutputStream(file);
66             byte buffer [] = new byte[4 * 1024];
67             int temp;
68             while((temp=input.read(buffer))!= -1){
69                 output.write(buffer,0,temp);
70             }
71             output.flush();
72         }
73         catch(Exception e){
74             e.printStackTrace();
75         }
76         finally{
77             try{
78                 output.close();
79             }
80             catch(Exception e){
81                 e.printStackTrace();
82             }
83         }
84         return file;
85     }
86 
87 }

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 }

Mp3Info.java

 1 package model;
 2 
 3 import java.io.Serializable;
 4 
 5 /**
 6  * 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
 7  * Mp3info实体类
 8  * @author kyx
 9  */
10 public class Mp3Info implements Serializable{
11    /**
12      * 实现序列化接口
13      * 可以把对象变成字节码从内存中发送出去
14      */
15     private static final long serialVersionUID = 1L;
16 private String id;
17    private String mp3Name;
18    private String mp3Size;
19    private String IrcName;
20    private String IrcSize;
21 public String getId() {
22     return id;
23 }
24 public void setId(String id) {
25     this.id = id;
26 }
27 public String getMp3Name() {
28     return mp3Name;
29 }
30 public void setMp3Name(String mp3Name) {
31     this.mp3Name = mp3Name;
32 }
33 public String getMp3Size() {
34     return mp3Size;
35 }
36 public void setMp3Size(String mp3Size) {
37     this.mp3Size = mp3Size;
38 }
39 public String getIrcName() {
40     return IrcName;
41 }
42 public void setIrcName(String ircName) {
43     IrcName = ircName;
44 }
45 public String getIrcSize() {
46     return IrcSize;
47 }
48 public void setIrcSize(String ircSize) {
49     IrcSize = ircSize;
50 }
51 //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
52 public Mp3Info(String id, String mp3Name, String mp3Size, String ircName,
53         String ircSize) {
54     super();
55     this.id = id;
56     this.mp3Name = mp3Name;
57     this.mp3Size = mp3Size;
58     IrcName = ircName;
59     IrcSize = ircSize;
60 }
61 //不带参数的的构造函数
62 public Mp3Info() {
63     super();
64 }
65 @Override
66 public String toString() {
67     return "Mp3Info [id=" + id + ", mp3Name=" + mp3Name + ", mp3Size="
68             + mp3Size + ", IrcName=" + IrcName + ", IrcSize=" + IrcSize + "]";
69 }
70 //toString方便测试鉴定
71 }

Manifest

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.example.mp3player00"
    android:versionCode="1"
    android:versionName="1.0" >

    <uses-sdk
        android:minSdkVersion="4"
        android:targetSdkVersion="4" />

    <application
        android:allowBackup="true"
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name"
        android:theme="@style/AppTheme" >
        <activity
            android:name="com.example.mp3player00.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>
        <service android:name="service.DownloadService"></service>
    </application>
    <uses-permission android:name="android.permission.INTERNET" />
     <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>
 <uses-permission android:name="android.permission.MOUNT_UNMOUNT_FILESYSTEMS"></uses-permission> 
</manifest>

调试中的问题

无法创建路径

问题根源

成功下载mp3文件

posted @ 2010-10-16 09:57 Kstyjobx!! 阅读(812) 评论(0) 编辑收藏举报

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mp3播放器（四）（从服务器端下载mp3文件+service的应用+SDcard操作）

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